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Can a home be sealed too tightly?

While this problem is unlikely, the answer is a qualified yes. Typically in an older home, sealing it too tightly is not a problem. However, even if you do, you don't want to be losing heat to the outdoors, you will want to find another way to ventilate your home without wasting energy. It is essential that you do all the sealing necessary prior to installing any insulation, otherwise you may have trouble locating any leftover leaks. Once you're satisfied that you've sealed all the leaks, it is time to insulate.

How do I find leaks? Where should I look?

What you'll really need to do is to evaluate your entire home from top to bottom. Make a full diagram of every room including your attic and basement.

The easiest leaks to find are the ones that you can feel either when the wind is blowing or when it is very cold outside and you feel a cold draft. In truth, you lose more heated air through leaks in your attic or your basement. It will really pay for you to identify any leaks and either insulate or seal against them. One trick is to look for dirty insulation, indicating that there is air-flow in this area.

In the Attic: Pay special attention to doors, windows, wiring holes, any plumbing vents, recessed lighting soffits, and in the basement where the foundation meets the wood. Make note of slanted ceilings over stairways and where wall and ceiling meet. Pay particular attention to any dropped ceilings. All of these places have stud cavities that are open to your attic and can be a major source of an air leak. The attic is a pretty easy place to insulate for a do-it-yourselfer. For those of you who have a finished attic, seal behind the side-walls, or kneewalls. Many times this empty space is unsealed and uninsulated.

Look for areas where you have a leak that may be buried under the insulation. Look for areas where the insulation is dark and dirty as a result of a flow of air passing over a single area. You might also see frosty parts on the insulation where the warm moist air of the house hits the freezing attic air. (No, you don't have to replace this insulation, particularly if it is fiberglass. Cellulose insulation could have compacted, diminishing its effectiveness, so you'll want to add more to these areas.

In the Basement: The most common place to find an air leak in the basement is right at the top of the basement wall where the block or cement contacts the wood framing of the house. If your basement is unfinished, this is a pretty easy task. The reason this is such a big source of leaks is that the top of the wall is above ground, and outside air is drawn in through the gaps and cracks that develop in this area. Check the entire perimeter of the basement for leaks. Even if you can't see any cracks in the rim joist cavities, seal the top and bottom anyway. Check for bump out areas under bay windows that extend past the foundation.

Seal any areas in the ceiling of the basement that go to the upper floors like holes for wires, water supply pipes, drain pipes, your plumbing vent stack for venting sewer gases and the fireplace flue.

Closing off these leaks will pay you back in a big way when it comes to paying your heating bill. Don't worry too much about finding every tiny little leak. It's the big air leaks that will give you the biggest return in energy savings.

How do I know if I have a problem?

One of the easiest ways to discover if you have a problem is to hire a contractor who has specific diagnostic tools to see if you have any air leaks that you need to address. A contractor will have specialized equipment such as the following to help you to determine where you have leaks:

-> Infrared Camera – this takes images that shows heat variations that might indicate leaks.
-> Flow Hood – this measures the amount of air that flows through a register.
-> Blower Door – this is a variable speed fan that mounts in a doorframe. It is used to measure air leakage by pressurizing and depressurizing a home.
-> Manometer – this measures a pressure difference from one location to another.
-> Duct Blower – this is another variable speed fan that mounts to a duct system to help determine if there is air leakage in your ductwork.

How do I seal ductwork?

It is thought that about 20% of all your energy loss can occur inside the ductwork of a home that has forced air heating and cooling systems. Your heating and cooling bills are very high, and the house doesn't feel very comfortable. For all the ductwork that is hidden behind walls, it is almost impossible to seal. However, for any ductwork that is accessible through the attic, basement, or crawlspace should be addressed. For these areas you use a duct sealant or mastic. Also, be sure to insulate this ductwork very well in basements, garages, and attics to avoid any significant energy loss.

Is there a difference?

There is quite a bit of difference in all the various types of insulation. You need to evaluate the different forms of insulation and use the best one for the particular application you're planning.

Should the attic door be sealed?

Absolutely! This is very easy to do with self-stick weather stripping attached all the way around the hatch or door opening. You want to make sure the weatherstripping is compressed when the door is closed. You can even insulate the actual door, or hatch by gluing a piece of rigid insulation cut to the size of your hatch.

What about a furnace or fireplace flue?

This is a real source of heat loss because building code requires at least one inch of clearance between the metal flue, and two inches from masonry chimneys and any material that can burn. This includes insulation. These gaps need to be sealed with aluminum flashing and high-temperature or heat-resistant caulk. Create a cage around the pipe or chimney using hardware fencing. This will keep the insulation far enough away from the pipe or chimney.

What is the purpose of sealing and insulating?

Everyone today is concerned about energy, its cost, and whether or not we're wasting it. The very first place to look is your own home. You alone are responsible for inspecting and then sealing and insulating the shell or “envelope” of your home. It s the easiest and most cost effective way to take control of the energy efficiency and comfort of your home. Did you know that you could save up to 20% on heating and cooling costs by taking some preventive steps? This could save up to 10% of your TOTAL energy bill!

What kind of insulation should I use?

Once your air leaks are sealed, it's time for insulation. Insulation needs to be what is a good application for the need. Remember, insulation keeps your home warm in the winter and cooler in the summer. The most common type of insulation is the typical fiberglass bats. Another choice would be cellulose, rigid foam board, and spray foam. There is another type of insulation that could be used that is a reflective board, or a radiant barrier that helps to save energy in parts of the country that get a great deal of sunshine.

Insulation is rated by what is called R-value, which is its ability to withstand heat flow. The higher the R-value, the better the insulation is. There are differing R-values recommended for different parts of your house like walls, attics, crawlspaces, and basements.

The single best place to add insulation is up in your attic. A great deal of energy is lost through the attic both in the summer and in the winter. If your insulation is even with the floor joists of your attic, you should put an additional layer of insulation. Most homes need an insulating factor of R-38, but in very cold parts of the country you will want to go up to R-49.

What kind of sealant should I use?

You'll want to seal these leaks either with caulk, spray foam or weather stripping. Use caulk or expanding foam around electrical wires and plumbing vent pipes. Be careful around the furnace flue; here you'll need to use high-temperature caulk around the pipe sleeve and the metal frame. Be very careful as this could be extremely hot if the furnace is in use. Try not to get any foam on your clothing as it is almost impossible to remove once the foam sets.