Shading and Windbreaks
Shading and windbreaks can play a large role in the energy efficiency of both your heating and cooling systems. Shading the exterior of your home in the hot summer months can help keep heat from building up on the interior and wind breaks can be beneficial in the winter months to help block harsh north and north west winds that pound on your home. This is important because the wind affects the amount of heat loss, comfort and durability of your home.
Shading typically comes from large trees located near your home but other buildings can also provide shading. The main thing we are trying to accomplish is to limit the amount of solar heat gain in the summer months. Most of this heat gain will be coming in through the windows. As the sun moves across the sky we will get morning light in the east windows, mid day light in the south windows and late afternoon light in the west windows. The morning light we get in the east windows is considered desirable by many people but it still is a heat gain on the house. West windows are nice for watching the sun set but think about when we have the hottest parts of the day, they are usually in the late afternoon. West windows can really produce a lot of heat. Trees or the overhangs on the house can easily shade south windows. The sun is high in the sky on those midsummer days so a decent overhang above the south windows will do a lot of shading. We can’t accomplish much shading with overhangs on the east or west because the sun is either rising or setting and is low in the sky.
Windbreaks work best when they are located some distance from the house so they deflect the wind up and over the roof. They can also be affective in controlling snowdrifts. It’s important that windbreaks are at least 15 feet from the house; closer and you actually trap heat that increases summer cooling costs. Many farmsteads have trees (usually pine trees) planted around the northwest corner of the property. This is a classic example of a windbreak. In urban areas, windbreaks can come in the form of buildings, landscaping and fences usually provided by the neighbors.
Check out the Arbor Day Foundation web site for detailed information on how to plant trees for shading and windbreaks. www.arborday.org Do two separate searches one for ‘windbreak’ and one for ’summer shading’. Remember we are in hardiness zone 5 when you select trees.
Take a walk around your house and see what you already have that might be beneficial for shading and wind breaks. On a sunny midsummer day take note of the sun that enters your house in the morning, mid day and evening. On a windy day, go outside and observe how strong the wind blows around your house.
The long-term goals would be to create a future windbreak and some future landscaping that would eventually provide summer shade. Any landscape plans should include consideration of how it will affect the sun and wind exposure on the house many years later.
If you have plenty of space on your property, some reshaping of the grade could be done that may deflect wind. Some fencing in the right place could also help.
To help with heat gain, you may add awnings over the windows on the south face of your house. On average a 30” shade over the window will do a great job of shading in the summer yet let sun light in during the winter months. On the east and west side you can use your interior drapes and blinds to cut down on the amount of heat gain.
One thing we don’t think about much these days is the idea of exterior shutters. Many homes have ‘fake’ shutters for looks but there was a time they served a purpose. Shutters on east and west windows control the heat gain at the exterior before anything enters the house. Shutters can also be used to add a layer of insulation to the window, protect the windows from storm damage and add a layer of security. Wouldn’t that be fun to have something so low tech yet so effective on you home?
Exterior Water Management
Exterior water management in homes built between 1975 and present, share some similarities in their construction. They consisted of mostly grading your property so surface water moved off and into a gutter or ditch as fast as possible. Houses in developments and subdivisions were beginning to be built closer together making the waterways between the homes narrow and steep. In later homes sump pits with pumps were added to remove water that collects around the foundation and under the basement floor.
Now let’s take a look now at what you have:
Start in the basement and take note of any areas that are damp or look as though they have been damp in the past. Be sure to pay careful attention to the location(s) in the basement where you are seeing signs of moisture. Look for a sump pit with a pump in it. If you do find one, make sure it has a lid and it is sealed for radon and soil gasses and take note of where the discharge line goes.
Now let’s go outside and have a look around. Walk around your home and take note of the height of the dirt next to the house and to about 10 feet away. It’s not unusual for the dirt in the area around the house where the foundation was excavated to settle some. Take note of which direction the ground slopes, toward the house or away from the house and about how much difference there is in height. As you’re walking around also note where the downspouts from the gutters dump out and which way the water would likely run. Another thing to look for is where there might be high volumes of water coming off the roof at the valleys.
Next we’ll walk around the property looking at the grade beyond the house. Are there areas where water will pool after a rain? Does the neighbors’ house sit higher or lower than yours and does any of their property slope toward your yard? And where does the water go when it leaves your property?
The last thing to take note of is your hard surfaces such as the driveway or a patio. Note how much of your property is covered with hard surfaces and where the water drains to.
Draw a map of your property showing the directions the water flows around your home.
Our goals here are fairly simple, we want to have good drainage around the house so the basement stays dry, and we want to keep as much of the rain water on the property as we can (I know this sounds crazy but be patient, we’ll explain).
We’re going to deal with the drainage in two steps. First we’ll work with the area around the house and next we’ll work with the rest of the yard.
- The grade around your house should slope away from the foundation at least six inches in the first ten feet. It’s very important that water coming off the roof and from around the house not pool next to the foundation. This may not be easy to do if the landscaping is thick and mature. Do the best you can. If you’re having water problems in the basement adjacent to a low area in the grade, the landscaping will have to be removed so the grade can be corrected. It’s not just the dirt areas we’re concerned with, you also need to consider any concrete walks or patios that run along the house. They may have to be raised or replaced to keep water moving in the right direction.
- Now the gutters – who loves gutters? Not us, we think they’re a pain in the kiester. Generally they are an evil necessity unless you have very deep overhangs on your house, (three feet or more) and you could possibly remove the gutters. The gutters have to be clean to work; there is no way around this. Gutter toppers seem to do well in light rain but when you really need the gutter to perform (in a heavy rain) you need as much open space to catch water as possible. It’s best to try to eliminate the source of plugged gutters, which is leaves, sticks, walnuts, etc. Prune the tree limbs that hang over the house to help reduce the leaves that fall on the roof. If you must use a topper, try the removable, open screen type that lets as much water in the gutter as possible yet can be flipped up to allow for cleaning. If you have a large roof, you may want oversized gutters or if there are water problems in the basement in the corners where a roof valley dumps a lot of water, you may need to put a splash flashing on the gutter to help keep the water from overflowing.
- Next the downspouts: The best situation is an oversized downspout that dumps on a splash block that guides the water away from the foundation at least four feet or more. An oversized down spout will pass debris better and using a splash block instead of more down spouting as a leader is easier to take care of. Leaders (extensions) tend to get smashed or disconnected and then the whole system is compromised.
- Now let’s talk about something fun – water collection. Collected rain water can easily be used for watering gardens and landscape plants. If you would like to collect rain water use a rain barrel and collect from one of your down spouts. Or if you want to collect more than a rain barrel can hold, you can make your own water collection cistern. This water is not to be used for drinking. Collected rainwater can easily be used for watering gardens and landscape plants. The old cisterns had a hand pump mounted above them and you can still find these at auctions and in Grandma’s barn. If you don’t want to pump the water by hand you can use an electric pump to do the same thing. If you don’t have a cistern but would still like to collect rainwater, use a rain barrel or make your own cistern. You will be surprised at the amount of water you can potentially collect. For a simple calculation take the square footage of your home and multiply by 32 (rough average of yearly precipitation in inches) then divide by 12 (gives you cubic feet of water) and multiply by 7 (number of gallons in a cubic foot). Example – 1000 square foot house x 32inches divided by 12 equals 2667 cubic feet of water times 7 gallons per cubic foot equals over 18,000 gallons. WOW! If you live in town, be sure to check with your water utility for any restrictions on the amount of water you can collect; there may be rules you need to follow. www.rainwatercollection.com
Now for the rest of the yard. Our main objective is to keep as much of the rain water as we can on the property. In town, most of the time runoff heads toward the street to the storm sewer and dumps in the local river or stream. In rural areas, the water heads to the ditch and eventually to the river as well. Along the way it picks up yard chemicals, pet waste, gas and oil from the road, and other garbage along the way. This is not helpful to Iowa’s rivers and streams. Besides, don’t we want to keep as much water on our property as we can to nourish our plants?
- The first thing we want to do is reduce the amount of impervious surface (typically concrete) we have on our property. Some municipalities are beginning to charge a storm water fee based on how much hard surface your property has. This may not be very practical to do unless you have planned to remove or replace some of the existing concrete you already have. Consider reducing the amount of hard surface around your home in your plans. If you want to have some hard surfaces, consider pervious concrete or brick pavers (reclaimed is best) when its time to replace the concrete. Both will let water soak through with less run off.
- Second, look for a good place to install a water garden. This may be that low spot you saw when you were assessing the land, or pick a place where there is a high concentration of water moving across the ground during a period of rain. These could be good spots to collect a significant amount of water. If you are not collecting roof water in a cistern you may want to divert the downspouts via a tile to the water garden. One note of caution though – do not locate your water garden where it will cause trouble with your foundation. It should be located at least 50 feet away from the house. www.rainscapingiowa.org
- If you don’t feel you can keep your rain water on your property, at least try to slow it down so it has time to soak into the ground. Think about how the native prairie slowed and filtered the rainwater before it made its way to the rivers. Native plantings in your yard are always a good choice and some strategic landscaping could help slow down the water flow.
A good resource is EEBA’s (Energy & Environmental Building Association) Water Management Guide. www.eeba.org
Now that you’ve finished this section, take some time to fill out this questionnaire to assess your home’s exterior water management. Keep it with the other questionnaires to build a resource you can reference when tackling projects at home.
(Let’s find out what you have)
Since the late 70s and the beginning of the energy crisis, (remember when we had to drive 55 on the Interstate) windows have had a focus on energy efficiency. There has also been tons of testing, ratings and certifications available to help the homeowner make decisions about window purchases. To determine what qualities your windows have, start with the manufacturer. The first thing we need to do is to try to determine the brand of windows you have. This may be easy; some manufactures print their name on the window hardware or on the glass in one of the corners. If you can’t find the name on the window, you may be able to find it on the building plans if they are still available or from the builder if they are still in business. Once we know the window manufacturer, we should have access to a wealth of information about your windows. The insulating value, solar heat gain figures, and air leakage rates as well as specifications that show the different parts that make up your windows.
Windows could be made of several different materials including, wood, aluminum, vinyl and fiberglass. Even though some of these materials are considered ‘maintenance free’, there can still be problems with each of them. Next let’s make a visual inspection of the exterior of the window. Wood windows may have signs of decay (soft wood). If your windows are wood covered in metal, it may be harder to see the decay. Look at the joints and edges for swelling and any exposed wood when the window is open. Windows made of all metal probably won’t show many issues on the exterior, but you may find some separation at the corners or deterioration of the finish. Fiberglass and vinyl windows can expand and contract quite a bit, so check the corners to see if they are holding together well and make sure the frames are still straight and not deformed.
The glazing systems in modern windows can vary quite a bit. The most common will be a double glazing (two panels of glass, one in front of the other). You may also have a triple glazed window (three panels of glass) and some manufactures used layers of clear film between the glass to create even more air spaces. The air spaces help give the window a better insulating value.
There are also different gasses that can be injected between the glass panels that add insulating qualities. Lastly, there could be reflective coatings or tint added to the glass to affect solar heat gain. If you are unsure about your glass, it’s best to spend some time trying to find out what options your manufacturer offers (offered) to help narrow down the possibilities. You may need a building professional to help determine what you have. See COSC’s list of qualified contractors on our website.
On the interior, check the operation of the window. The window should operate smoothly and come closed so the latching hardware can seat the window snuggly against the weather-stripping.
If you have a blower door test done on your home for an energy audit, use some smoke from a blown out candle to check for air leaks around the window while the house is under pressure.
Our goal here is to keep your existing windows operating smoothly and looking nice. Most modern windows should not be considered for replacement unless there are serious problems with the condition of the window. Our second goal is to understand the energy qualities of your windows which will affect other projects you may want to do on your home at a later date. For example the sizing of a replacement furnace can be affected by how efficient (or inefficient) your windows are.
- If you know your manufacturer, learn about your windows. Important things to know are the U-value of the window (not just the glass) and the solar heat gain coefficient. These are numbers used in calculating heating and cooling loads on your home.
- If your weather stripping is worn, replace it using the manufacture’s replacement parts and installation instructions.
- If you have rotted wood and it has not progressed to the point where the window is falling apart, you can remove the decay and install patches of either wood or catalyzed putty purchased at your local hardware store. Some parts may be available from the window manufacturer.
- Fiberglass and vinyl windows with damage are usually repairable, but you need to start with the manufacturer to see what they recommend.
- Fogged windows mean a seal has broken in the glazing and will need to be replaced. Again, contact the manufacturer for guidance.
If you have to buy new windows:
- Buy the best quality window you can afford. Even though there are many replacement window companies, your best choice may be with an established, reputable window manufacturer. Most companies will make windows to fit your home for a small additional charge.
- Windows in bedrooms should meet egress requirements. This allows easier emergency escape for the folks inside and easier access for firefighters to get in. Many codes do not require egress windows to be installed as a replacement, but don’t you think it’s a good idea to do it if you can?
- Windows should meet a minimum of Energy Star standards for energy efficiency. If you can improve on the efficiency please do! Your new window should also be certified by the NFRC, (National Fenestration Rating Council) an independent energy rating organization.
- Purchases windows made of recycled metals and FSC certified wood if possible.
- Even though your old windows are in bad shape, if you deconstruct them, many of the materials can be recycled or repurposed. For example: the glass can be used in a cold frame for your garden.
Now that you’ve finished this section, take some time to fill out this questionnaire to assess your home’s windows. Keep it with the other questionnaires to build a resource you can reference when tackling projects at home.
Insulation and Air Barrier
(Let’s find out what you have)
Virtually all Iowa houses during this time frame will have some type of insulation in the walls and attic. The most common insulation is fiberglass. In the attic, it is usually a loose insulation blown across the entire attic. In the sidewall, it’s a sheet of fiberglass called a batt that fills the entire stud cavity. There may also be a sheet of foam board or asphalt impregnated fuzz board on the outside of the wall as well. The amount of insulation in the attic can vary from six inches to more than twelve inches. Fiberglass is the most common material out there but there are other insulation materials that could have been used including cellulose, open and closed cell foam (in various forms), and even cotton.
A peek in the attic will tell you what you have. Be sure to look all the way down to the bottom because you may have a couple different types of insulation that have been added one on top of the other. Measure the thickness of each layer so we can determine the R-value of the whole insulation job and note if the insulation is loose or in batts. One word of caution: fiberglass can really irritate your skin, eyes and lungs. Some fiberglass is worse than others; the yellow stuff seems to be the worst, then pink, then white. At the very least wear long sleeves, a dust mask and eye protection when rummaging around in the insulation. The pros wear Tyvek suits when they go in attics, you can get one at the local paint store. You may feel itchy after being in the attic and a cool shower with lots of soap will help.
While you’re in the attic let’s look for signs of an air barrier. One place to check is at a location of a light fixture on the ceiling below. Pull the insulation back and see if you can see light or feel air coming from around the electrical box. Does it look like there is a plastic sheet on the ceiling of the room below? This would be a vapor retarder not all houses put them on the ceilings in this time frame but many did. Make a note of what you observe.
The walls can be a little more difficult to determine what you have. Here are a couple of things you can look at to help. One way to check is remove an outlet cover on the exterior wall. Sometimes there is extra space around the drywall or plaster where the electrical box pokes through and you can see into the wall cavity. (Warning: be careful of electrical exposure) This is also a good place to check the air barrier. Look for the plastic sheeting again. Some houses used a paper facing on the insulation in place of the plastic sheeting so make a special note if you see paper. You may be able to feel air movement around the outlet box but not necessarily. Sometimes a foam gasket has been placed behind the outlet plate cover to stop a drafty outlet.
Another way to check is in a closet or some other inconspicuous area. Remove a base board and cut a small hole in the drywall behind where the base would be to have a look.
One more way to check wall insulation is to take a long small diameter twist drill bit and drill a small hole into the wall in a place that does not matter. Examine the dust and stuff the drill brings out to see if there is any insulation in the mix. This will only tell you the type, if any, of insulation not how much you have or if there is a plastic barrier on the wall.
Let’s also take a look at the boxing or rim joist area (framing area on top of the basement wall) in the basement. This area is exposed to the outside too. Most commonly there will be pieces of fiberglass batt insulation fit between the floor joist. Make a note of what you see. Check for an air seal in this area too. Turn the lights out and look for light from the outside; you may be surprised at what you see. If it has been sealed you will see caulking at the joints where two differing pieces of wood meet. Gaps may have been caulked but it’s pretty rare to see that.
While we’re in the basement note if the walls are insulated. You can use the methods listed above to check in the finished spaces. Unfinished rooms usually show only the foundation wall but this does not mean you have no insulation; it may be on exterior. There was a time when basements were insulated with large rolls of plastic covered insulation, like six feet wide. The insulation was attached to the top of the foundation wall and just hung down from there missing the floor by a foot or two. Its been called an ‘insulation diaper’. Look behind the diaper for signs of mold. Note if you have the diaper and if mold is present. Insulation on the exterior of the foundation should have some type of covering over it between the dirt and the bottom of the siding. If you dig down a foot or so you should be able to see the insulation if there is any. Most likely it will be a foam board; note how thick it is and what color it is. Crawl spaces are not common but if you have one, note the walls and boxing area just like the rest of the foundation. The floor of the crawl space should be noted too; if it has a concrete floor or is exposed dirt.
Now you know your type of insulation and the amount let’s figure your R-value. Use the chart below to calculate your R-values in the walls, ceilings and boxing.
|Material||R-value (per inch)|
|High density foam board (blue and pink)||5|
|Bead board (white)||?|
There is some testing you can do to help determine how well your house is insulated and sealed. One – you can have a blower door test done on your home. An energy rater usually does this; preferably a HERS certified energy rater. The blower door (an insert temporarily installed in an exterior door frame with a high volume fan attached) will pressurize your home and accentuate the air leaks. Just feeling around outlets, doors, windows and plumbing pipes you can find many of the air leaks in your home. A smoke tool can also be used to visually see the leaks when the smoke is released near an area you’re checking. The rater can also run a calculation on your home to determine how much air is leaking from your home. This measurement is in Air Changes per Hour (ACH). There are two numbers you can get, – one is ‘ACH natural’ which is the amount of air that exchanges in your home without any fans or other pressure. This is not the best number you can use; a better number is ‘ACH 50’. This is the number of air changes in your home when it’s under pressure with the blower door fan. If you want, most raters can tell you approximately how big a hole you would have in your home if all the air leaks were put together in one place. Don’t be surprised if it is pretty big, like a hole, two or three foot square.
The second test can also be done by your certified HERS rater (ask for a copy of their certification certificate). This test uses an infrared camera to show images of temperature differences in the walls and ceilings of your home. The images will help you determine weak spots in your insulation. Copies of the images will be useful as you make improvements to your home. It’s a good idea to have the rater help you interpret these images because sometimes they show weird things like your silhouette on a window. It is also best to do this when there is a large temperature difference between the inside and outside of your home.
Lastly ask the HERS rater about combustion air for your furnace, water heater and any other appliance in your home that burns fuel. Your house may have make up air that dumps into the mechanical room (an open pipe directly from the outside, usually six or eight inches in diameter) or it may leak air enough to feed the flame and draft the flue pipe. As you seal up your home this could become an issue. Talk about your plans to improve the insulation and air seal. Find out how they would like you to monitor your combustion appliances as you tighten up your home.
Ultimately we want to have a tightly sealed building envelope with a nice amount of insulation. Here we can work with numbers; let’s aim for a building with an air change per hour of 3 ACH 50 or less. This would be a very tight building and will require some effort to achieve. On the insulation side let’s try for an R-15 on the basement walls, an R- 20 on the other exterior walls and boxing areas, and an R- 60 in the attic. These goals should not be difficult and you may already be most of the way there. So let’s get started.
If we’re going to do this right we have to think about a few other projects: bath and kitchen fan vents, door and window seals, indoor air quality, back drafting and more. It’s always temping to take that energy rebate from the utility and blow a bunch of insulation in the attic right away but if we do a little work up front we’ll get a much better job overall.
So here are the steps, they may not all apply but the order is very important.
- We are taking a top down approach so we’re starting in the attic. There are several projects to do before any insulation goes down and actually we may want you take any insulation you have in the attic out! If you have a plastic vapor retarder on the ceiling (the plastic you can see from the attic after you pull the insulation back) you can skip this step and go to number 2. If not let’s take out the insulation you have. You may be able to roll up the insulation if it’s in batts but most likely it’s some type of loose insulation. The easiest way to deal with this is to have the blow-in insulation guy come out, reverse the operation, and suck out the insulation (depending on what you have it may be reusable). Now we have a nice clean attic to work in.
- Any bath or kitchen exhaust fans that are venting in the attic space need to be vented up and out the roof or over and out the side wall. It is critical that we do not add any moisture to the attic space once we’re done. Vents going out the side wall usually end up buried in the insulation and this is good. If your vents need to go up above the insulation, the pipe needs to be insulated. This prevents condensation from dripping back into the house. Metal rigid pipe is best, metal flex pipe is okay (not great) and please don’t use plastic flex pipe. Seal the joints with mastic (not tape). If you have any plans to add a vent now is the time to do it. You don’t want to be crawling around in your newly insulated attic messing things up later.
- Next, any plumbing vent pipe coming through the attic needs to be checked out. Hopefully they are in good shape but if not, they need to be replaced now. And the new pipe needs to go through the attic floor (the ceiling below) so we can make a good seal around it in the attic space. Here comes a special secret detail – as the plumber is fitting the pipe, before he attaches it to the pipe below, slip a piece of rubber roofing with a hole cut in it over the pipe that will act as a gasket. Once the pipe is attached, slide the rubber down to the attic floor and attach it to the wood plate the pipe comes through. Plumbing pipes move up and down with temperature changes and this seal will stay in place as the pipe moves.
- Look around for any metal pipes coming from below that could be hot (warm) like from a fireplace, water heater or furnace. There is usually a requirement that there be at least a two inch space around this pipe of non-combustible material. To make a seal you will need to fit some sheet metal around the pipe and caulk it with high temperature caulking. Be sure to caulk the seam in the sheet metal as well. Don’t worry about caulking the sheet metal to anything else. Now you need to build a box or cage of sheet metal around the pipe to hold the insulation back two inches. (Insert a picture) Note: not all metal pipes need to be treated this way. Some are rated for insulation contact; you will have to determine what you have. If you’re unsure, put in the air space just to be safe.
- If your house has been remodeled, there may be some electrical junction boxes in the attic. Make sure all the wiring in the attic is in good shape and meets code. You may need to have your electrician come and take a look. He would rather fix it up now than when your attic is stuffed with insulation.
- Recessed lights that have been cut through the ceiling and stick up into the attic space may need to have an airtight box fit over them unless they are in an ‘air tight housing’. Allow at least a one inch space over the top of the light and notch the plywood as needed around the wires so the box sits nicely on the attic floor. It can just sit there; no need to fasten it.
- This step is for you folks with the plastic vapor retarder on the ceiling. We’re going to use this as our air barrier. All the things we’ve worked on so far go through this plastic sheet. We need to pull the insulation back from around all these penetrations and seal the pipes, wires, fans, recessed lights and anything else that pokes through the plastic. You can use caulks, spray foam, mastic; whatever will stick to the plastic and hold up well over time. Also, wherever there is a ceiling light fixture in the rooms below, there will be an electrical box sticking through the plastic. You may have to hunt these down because they will be buried in your insulation. And lastly, the interior and exterior walls below (you’ll see the top plate from the attic) will need to be sealed to the plastic as well. We know this sounds like a lot of work and it’s a really crappy job crawling around the insulation, but do the best you can. A well sealed attic can stop ‘the stack effect’.
- Attics need to be vented. Most roofs have vents in the soffits that work with vents in the roof peak or near the peak. You need to make sure that the insulation you add won’t impede the flow of air from the soffit vents to the ridge vents. This is done with something called a ‘proper vent’. They are usually made of plastic, cardboard or Styrofoam. They come in a couple of different widths and are usually about four feet long. All types do their job well. I would pick the cardboard just because it’s more organic than plastic or Styrofoam. These vents are placed in every rafter space over the exterior wall plate, extending into the attic and stapled to the underside of the roof sheathing. Be careful not to squash then; remember we want air to flow.
- Prepare the attic access. If we step back and look at how we get into the attic, it’s pretty obvious that it’s just a big hole in the ceiling. You may even have a stair that walks right up there. The first step is to put an insulation barrier around the perimeter of the hole that will hold back the loose insulation and keep it from rolling down the hole. This usually is made of plywood strips about 12” to 14” tall. The second step is to make a cover for the hole that can be sealed and insulated yet easy to remove.
- Some of you may have heating and cooling ductwork in your attic. This requires special attention and we will refer you to the ductwork section of HOME MATTERS for specific information. The important thing to know is unsealed ductwork creates problems of all kinds and flex ductwork does not always work the way it should. So, please don’t skip this step!
- Now you have an attic that is prepped for a proper insulation job. If you have the plastic sheeting, you can skip this step, although the part about using foam at the exterior walls may interest you. The first step is to have your insulation contractor apply two inches minimum (very important) of high density foam or 1.9 Lb foam (also very important) to the entire attic floor. Plus we want this spray foam to fill the entire area over the exterior walls all the way up to the roof sheathing and proper vents so that we have a thicker layer of foam where we don’t have much space for insulation. The spray foam should be continuous going up and over any recessed light boxes, ductwork, bath fans, and around plumbing pipes, and anything else coming through the attic. This is going to do three things for you; all really important.
- High density foam has almost an R7 per inch of foam, a lot of R value per inch. This will give us a much better R value over the exterior walls which are usually a very weak area of the overall insulation job.
- The continuous layer of foam will create a complete air barrier in the entire attic space. No air leaks!
- Using the high density foam also creates a vapor retarder that keeps moisture from entering the attic space and collecting in your insulation. This can show up as a water stain on your ceiling and it can ruin the R value of your insulation. If all has gone well, we have about an R14 in the attic so far.
- We’re going to add a project here that’s not related to the attic. Because we have the spray foam contractor here, let’s take him/her to the basement and apply a 3” layer of foam in the boxing area to insulate and seal it up. It’s not as critical to think ahead in this area because it’s pretty accessible (unlike the attic) and it can be repaired with canned spray foam if a future hole needs to be added.
- The last step is to finally add the blow-in insulation we wanted to put in way back in step one. Cellulose is the preferred insulation. It’s made from recycled paper and holds it’s R value well over time. We want to get to an R60. If you used the spray foam, we have about an R14 so we need to add about another R46. If you left your original insulation in place, you can subtract the R value you have from 60 to determine how much more you need. Notice we’re not talking about how many inches we need to add; that’s because to get to the R value we’re after, we need to add a certain number of BAGS of insulation. Right on the label it will tell you how many bags per 100 square feet you need to get the R value you want. Make sure your insulator knows you expect X number of BAGS to be installed in your attic (not inches) based on your square footage. Note: you could do this step yourself with some rental equipment but its best to check the pricing on hiring the job done as it may not be worth the trouble to do it yourself.
That was intensive to say the least but a job well done!
Two additional topics related to attic insulation:
- Vaulted Ceilings: You may have some rooms in your house that have vaulted ceilings and insulating them can be a challenge. Many times there just isn’t enough room to get a decent amount of insulation in the space between the sheet rock and the roof. It also can be difficult to get to. One way to get access to the vaulted spaces is when you replace your roof shingles. When the old shingles are torn off and before the new shingles go down, you can remove the plywood roof sheathing and add insulation from above. Use insulation with a high R value per inch since you don’t have much space to work with, possibly only five or six inches. Try to use a system that does not require venting so that you can fill the whole space. One other thing to consider is adding a layer or two of high density foam board to the ceiling from the underside. You can gain about an R5 for every inch you add and you will be creating a complete thermal break. Unfortunately you will have to put up new sheet rock over the foam.
- Conditioned Attic Space: Some people really like their attic storage space; we don’t. A modern attic should be for insulation only and if it is sealed and insulated properly, there is no reason you should need to be up there. However some homes do have good attics with floors strong enough to hold a load, enough headroom to stand up in and a decent stair to access it. In this case you should consider insulation in the rafter spaces rather than on the attic floor. There are insulating systems you could use that would do a good job of insulating and sealing the attic rafters and some do not require venting. If your attic is important to you as storage space, a conditioned attic space is what you need.
Whatever your situation is, remember to take care of the venting, repairs, and air sealing before you do the insulation.
mastic sealed duct work
rubber gasket for pipes
spraying attic to seal
cardboard proper vents
attic door cover
attic flex ductwork
conditioned attic space
We are ready to talk about the sidewalls, and the basement. Our two objectives here are to insulate and air seal. It would be highly unusual for the exterior walls of your house not to have insulation and at least a plastic vapor retarder. Most of the work has already been done (Whew!!) The basement may be another story (Crud!) If you feel you need to address some concerns about cold spots in your walls (this is where those infrared images come in handy) consult your insulating contractor about your options. Our main concern is to slow down the air leaks. There are only a couple of areas to address. Here are the steps:
We are ready to talk about the sidewalls, and the basement.
Our two objectives here are to insulate and air seal. It would be highly unusual for the exterior walls of your house not to have insulation and at least a plastic vapor retarder. Most of the work has already been done (Whew!!) The basement may be another story (Crud!) If you feel you need to address some concerns about cold spots in your walls (this is where those infrared images come in handy) consult your insulating contractor about your options. Our main concern is to slow down the air leaks. There are only a couple of areas to address.
Here are the steps:
Now to the basement: First a quick note, if you have water problems in the basement they need to be corrected before any insulating is done. Now if you have addressed your windows and exterior doors (covered in other areas) you are ready to have your HERS rater back to see how you did. During this next testing you need to have your rater run a check on how well your combustion appliances draft; water heater, furnace, fireplaces etc. Because you’ve done such a good job sealing up your home they may need make up air to keep from back drafting. This is critical to your safety! Carbon monoxide will be introduced into your home if a combustion appliance is back drafting.
Now to the basement: First a quick note, if you have water problems in the basement they need to be corrected before any insulating is done.
Now if you have addressed your windows and exterior doors (covered in other areas) you are ready to have your HERS rater back to see how you did. During this next testing you need to have your rater run a check on how well your combustion appliances draft; water heater, furnace, fireplaces etc. Because you’ve done such a good job sealing up your home they may need make up air to keep from back drafting. This is critical to your safety! Carbon monoxide will be introduced into your home if a combustion appliance is back drafting.
At this stage, it is important to consult with a certified HERS rater or an HVAC professional to design a ventilation system to provide good air quality. This may include additional exhaust fans or a heat recovery ventilator.
This may seem crazy that we worked so hard to seal up the house just to bring in outside combustion air. The important thing is that you are now in control of how much and where that air comes in. Good Luck!
Now that you’ve finished this section, take some time to fill out this questionnaire to assess your home’s insulation. Keep it with the other questionnaires to build a resource you can reference when tackling projects at home.
Heating and Cooling
Most homes in Iowa from 1975 to today would have had a forced air system installed. This is a system that heats and cools the air in the home and pushes it through a ductwork system to all the rooms in the house with a fan located in the furnace. In most homes the basement is the location of the heating equipment and the ductwork. If your house has central air conditioning there will also be a unit that sits outside, that is the compressor.
The heating system burns fuel (mostly natural gas or propane). This is an actual fire or series of flames that heat an exchanger in the furnace that air is blown over to send the heat throughout the house. The air conditioner works much like your refrigerator. The compressor unit outside your house, which has a compressor (obviously) and a fan, pressurizes a coolant in piping. As the coolant is compressed it gets cold and gives off heat. The fan runs to remove the heat. The cold coolant in the piping is then pumped to a coil of pipes and fins located, usually, just above the furnace. The furnace fan then blows air over the cold coil sending the cooled air through the ductwork to the various rooms in the house.
If your home is more than 20 years old, what you see now is probably a new heating unit (furnace) and new central air unit. It may be hooked to some new ductwork but probably still uses the original stuff.
The ductwork system most commonly used will have a large metal supply air plenum coming off the furnace unit with 6” to 8” round pipes coming off the top or sides to feed air to the different rooms in the house. There will also be another plenum, usually about the same size but shorter called the return air that brings air back to the furnace from the different rooms in the house. Instead of round pipe from the plenum, the spaces between the floor joists are used. A piece of sheet metal was usually nailed to the bottom of the joist to create the space. In some two story homes the ductwork can actually be in the attic. Make a note if you have ductwork in your attic. In some of the newer homes the ductwork will be sealed with a mastic and possibly the return air runs will be in pipe instead of using the floor joist spaces.
There certainly are other systems used to heat and cool homes between 1975 and now. The furnace may be all electric using a heating coil instead of a flame, much like your toaster. Or you may have a boiler that pumps hot water to radiators in each room. A geothermal system is also a possibility in a newer home. Geothermal operates much like the forced air central air system we describe above but with two major differences. 1. The system can be reversed to use the warm air given off by the compressor to heat your home. 2. Instead of using the air temperature around the compressor unit as the starting point to create the heating or cooling, it has a series of underground pipes that use the constant temperature of the earth (about 54 degrees) as the starting point to create the heating or cooling. This means the compressor doesn’t have to work as hard and thus makes it very efficient. A geothermal system will also NOT have a compressor unit that sits outside; everything is inside in one unit.
There are a couple of questions to consider as you are looking at your current heating and cooling system. Before you even think about replacement units, consider safety first, especially if you’ve had headaches or flu like symptoms and if your house is not all electric, have a professional contractor check the back drafting throughout your house, especially if you have added any new fans in the bathroom, kitchen or elsewhere.
- How old are my heating and cooling systems? If your furnace or air conditioner is over 20 years old, you may be on borrowed time. Replacements are probably in the near future. Its not always the unit in the basement but its the exhaust pipe or pipes within the walls that may be failing which can be very dangerous. If you see holes in any exhaust pipes, please seek a professional contractor.
- Are my heating and cooling systems energy efficient? This may be kind of hard to determine. If you have done improvements on the building to make it tighter and more energy efficient, and you are dissatisfied with your energy bills, you should look at what a new unit would do for you. Your energy costs can be calculated (estimated) with a new unit so you can compare. A heating and cooling contractor can help with this. There is more useful information to follow regarding how to figure this out.
- Can I be comfortable in every room in my house no matter what the temperature is outside? It’s not uncommon to have rooms that just never get very warm or an upper level rooms that are hard to cool. This has more to do with your delivery system (the ductwork or piping) than the furnace or air conditioner.
That was the fun part, now for the not so fun but extremely important part – making sure the system is operating safely. Note – you cannot do this yourself; you have to have a professional inspect your system to make sure it’s operating as it should be. When we burn fuel inside our home (or anywhere for that matter) it gives off carbon monoxide. This is dangerous stuff and all of it needs to be vented to the outside. Your heating and cooling expert will check for proper combustion and venting to make sure your system is not letting any of this dangerous gas mix with the air you breathe inside your home. We can’t stress how important this is – it’s a matter of life or death. If your heating and cooling contractor is saying things about a cracked heat exchanger or back drafting you need to listen up and take immediate action.
It’s a good idea to have your system checked each fall before heating season to make sure it’s working properly. If you have central air-conditioning you should have a check done in the spring also just to make sure it’s working at its’ peak efficiency.
One thing you should have completed is the energy load on your home. What you want to know is how many BTU’s (British Thermal Units) of heat it takes to keep the inside of your home at 68 degrees when it’s 6 below zero outside, and how many BTU’s of cooling does it take to keep the inside of your home at 78 degrees when it’s 98 degrees outside. These temperatures are commonly used here in Iowa and you can adjust them to something more suitable to you but be careful, the idea here is to be able to properly size your equipment not oversize it. When we oversize the furnace and air conditioner it will become less efficient to operate. If we under size it we may not be comfortable in our home. Note: it’s pretty rare that equipment gets undersized by any heating and cooling contractor.
How do we go about getting this information you ask? It’s relatively simple; you ask your Heating and Cooling contractor for a ‘manual J’ calculation and if they look at you funny you may want to get a new contractor. A good one will ask for some information about your home and you will have most of it because you’ve already inspected and improved your insulation and windows. You also had a blower door test done so you know your air infiltration rate. Here’s what information will be needed:
- Square footage of each level of your home including the basement
- The ceiling heights of each level (we’re figuring out the volume of your home here)
- The square footage of the glass area on each side of the house labeled East, West, North and South and the U value of the windows.
- Square footage of exterior doors and what they are made of.
- How the exterior walls are built starting from the outside to the inside. Be sure to include the R-value of insulation in the walls as well as the finish and structural materials. Remember the basement walls; they will be different than the above grade framing.
- The R-value of the attic insulation and how the ceiling is built, i.e.: plaster on 2×6 ceiling joist spaced at 24 inches. (lines 3,4,5 and 6 above will help calculate the thermal resistance of your home)
- Lastly the air leakage figure. ACH50 (from your blower door test)
From this information the energy load in BTUs for both heating and cooling can be calculated. This is a constant figure and will not change unless you do something to the building envelope. This is also how you size the furnace and the air-conditioner to fit the loads on your home. You see now it becomes apparent why we do the insulation, windows, and air sealing before we put in the new furnace and AC. Our improvements to the house have affected the heating and cooling load; the better our improvements the lower the loads thus the smaller the equipment. LOOK, LOOK, were saving dollars not only on our energy bill but on the cost of installing the new equipment too!!!
There are some other tests that can be done on your heating and cooling system that will help you know how effectively your equipment is working.
One that you can do is measure the temperature in each room to get an idea of how even the heating and/or cooling is. Ideally you would check the heating system on a cold winter day and the cooling system on a hot summer day. Be sure to note the outside temperature along with your other readings.
You’re heating and cooling contractor or energy specialist can also check the airflow if you have a forced air system (the big blower fan in the furnace). The two areas to have them check are 1st, the airflow on each side of the furnace filter, and 2nd, the airflow at each register. This is important because restricted or poor airflow can greatly reduce the efficiency of your equipment and the comfort level in the house. We need to talk a little here about the air filter. Most systems will have a disposable filter like the type you buy at the big box store. Some of these are sold as super allergen dust busting mega great filters and they probably are. The thing is they could be screwing up your airflow in the ductwork so badly that your fan can hardly push the air through it. The best thing to do is use a cheap, fiberglass mesh filter and change it often (once a month or month and a half). There are filter systems that you can add to your ductwork system that are electronic or have large pleated filter material. You may want to consider a filter system like this especially if there is someone in the house with allergies. The important thing to remember is no matter what filter system you use there needs to be adequate airflow across the filter to provide the needed air to each room and keep the fan running at peak efficiency.
The super duper filters usually have a MERV rating. MERV 8 is good, MERV 10 better and MERV 13 or above is best. While the contractor is testing airflow, this would be a good time to try a couple different filters; all must maintain proper airflow from the furnace fan.
Once we are sure everything is working safely (our number one priority) our goal should be to have comfortable rooms (temperature wise) throughout your home at a reasonable expense. This may mean adjustments in the ductwork using your existing equipment or maybe replacing some outdated equipment with newer more efficient units. Or maybe everything is dandy for now and you can look at this when the furnace wears out later.
It can be very confusing to upgrade a heating and cooling system. Probably the biggest mistake that‘s made is assuming that a new furnace or air conditioner will solve all your problems. The distribution system (the way we are going to get the heat or cold to all the rooms in the house) is equally important and maybe even more so.
Heating and cooling improvements are not a do it yourself project and need to be done by a qualified heating and cooling contractor. Having said that, there are some steps to be taken that will help make sure you get a good system.
Since most heating and cooling systems in Iowa consist of a ductwork system connected to a forced air furnace with an air conditioner unit attached, we will proceed with this type of system in mind. If your heating and cooling system is different, there is still a good deal of useful information you can use so read on.
- Keeping in mind the proper order of things, you should have done your window, insulation and air sealing improvements first if possible.
- Have the load calculations figured for your house, preferably with required BTUs and cfm of air for each room, both heating and cooling.
- Have your temperatures of each room for both heating and cooling available.
- Test your ductwork system for airflow efficiency. This would be an opportunity to see how your filters affect your airflow. You may want to have a couple different ones around to try.
- Adjust your room registers to balance the airflow.
- If you feel there are problems in the air delivery, they should be addressed now. This can require some creative thinking by your heating and cooling contractor.
- Once you are satisfied the ductwork is capable of handling your comfort needs, then you can start looking at upgrading the furnace and AC units if you want.
Now let’s talk about the heating and cooling equipment.
- The first and probably only step is selecting your equipment. This is not an easy decision but we are here to help. Lets walk though some of the options.
|Central air and air sourced heat pumps||Furnaces – gas, fuel oil and propane||Boilers – gas, fuel oil and propane||GeoThermal closed loop||Mini split|
|Good HVAC||Cooling||13 SEER||N/A||N/A||14.1 EER||N/A|
|Heating||8.2 HSPF||90 AFUE||85 AFUE||3.3 COP||N/A|
|High efficiency HVAC||Cooling||14 SEER||N/A||N/A||15.5 EER||17.8 SEER|
|Heating||8.6 HSPF||92 AFUE||87 AFUE||3.6 COP||11.3 EER|
|Very high efficiency HVAC||Cooling||15 SEER||N/A||N/A||17 EER||20 SEER|
|Heating||9.0 HSPF||94 AFUE||90 AFUE||4.7 COP||11.8 EER|
Pros and Cons of each heating and cooling system:
Gas, propane or fuel oil forced air combustion system
Pro: quick temperature recovery, inexpensive equipment, can retro fit into most homes with a ductwork system
Con: combustion fuel source of Carbon Monoxide (CO), dirty, fuel price fluctuates
Central air conditioning with a frame coil and exterior compressor
Pro: can be fitted into existing forced air heating system (uses the same ductwork), whole house coverage, quick temperature recovery, contractor friendly since this is the most prevalent system
Con: susceptible to dirty environments (leaves, dirt, sticks) so requires occasional maintenance
Boiler radiant heat (combustion fuel boiler with piping to radiators)
Pro: quiet ‘soft’ heat
Con: cannot accommodate a cooling system, slow response times
Electric resistance heat-radiant (base board heaters, radiant ceiling panels, heated floor.)
Pro: in the case of baseboard heating, it’s cheap and easy to install & you can put controls on each unit for easy zoning, simple design with not a lot of complicated parts, electricity can be produced in a number of ways, and it will almost certainly be a fuel source we will have years from now
Con: electric heat is usually expensive, cannot accommodate a cooling system, can be cost effective with an all electric rate (see your utility provider), also suitable for air source and mini split heat pump back up
Ground sourced heat pump (geo-thermal) heating and cooling
Pro: electricity can be produced in a number of ways and will almost certainly be a fuel source we will have years from now, AC and Heating come from the same unit, equipment is inside & out of the elements, equipment is the highest efficiency of all possible units, cost effective with rebates and tax incentives, can also produce hot water
Con: can have slow recovery
Mini split heating and cooling
Pro: very efficient, can heat and cool, fairly easy to install, can be used in small spaces such as additions as an additional heating and cooling source, easily used for zoning, can be cost effective, good for remodeling since no ductwork is needed
Con: may need several units to do an entire house, some installations look like window AC units (visually more dominate)
These are a few of the most common heating and cooling systems offered here in Iowa. There are others but be wary unless you have a trusted energy specialist working with you to evaluate the system and how it will work in your particular situation. There is a lot of weird stuff out there and not all of it is worth your time, trouble and money.
Now that you’ve finished this section, take some time to fill out this questionnaire to assess your home’s heating and cooling. Keep it with the other questionnaires to build a resource you can reference when tackling projects at home.