Tightening and Insulating
STRATEGY: Your home should be sealed and then insulated. Air leakage usually amounts to 30-40% of your heating bill. Stopping air leakage is not only important for energy savings and comfort, but also to protect your home from the damaging effects of moisture. Air leaking into the walls from the interior of the home carries humidity with it. This can cause condensation. The condensation gets the insulation wet and could eventually cause the surrounding wood to rot.
MYTHS ABOUT AIR LEAKAGE
MYTH: Window and doors are the largest source of heat loss in the home and replacing old leaky windows with new energy efficient ones will yield tremendous energy savings.
FACT: Only about 15% of air leakage is through windows and doors, and if a single-glazed window with a storm is replaced with a double-glazed window, the conduction losses have not been lowered at all. The largest sources of air leakage are often overlooked. These include the band joist area at the top of the foundation, and holes into the attic. There are many good reasons to replace your windows: if they are structurally unsound, or to improve appearance, for ease of use or cleaning. But the cost of new windows is usually so high that it is difficult to justify their replacement on energy savings alone.
MYTH: Caulking around the outside of the house makes a house as tight as you can get it.
FACT: Caulking around the interior of the home around the woodwork, baseboard, band joist and in the attic is the only sure way to significantly reduce air leakage. Caulking on the outside is mainly for keeping rain out of the walls and doesn't significantly slow air leakage. It also doesn't stop moisture from entering the walls from the inside and causing condensation problems.
MYTH: Stuffing fiberglass insulation into cracks will stop air infiltration.
FACT: Fiberglass is a good insulator and makes a great furnace filter, but it doesn't stop air infiltration. It may slow it down some but caulking or a closed cell foam must be used in order to stop air infiltration.
MYTHS ABOUT INSULATION
MYTH: Heat rises, so if your attic is well insulated, your home is well I insulated.
FACT: Heat is lost in relation to the level of insulation, not the direction. The attic is often the easiest to insulate and therefore is usually done first. To be adequately insulated, a home must also have the walls and basement insulated.
MYTH: Since your basement isn't heated and dirt is a good insulator, you don't need to worry about insulating your basement walls.
FACT: If your attic and walls are insulated, an uninsulated basement can account for one third of your heating bill, whether you heat your basement directly or not. Your above ground basement walls have the same insulating value as a double-paned window.
MYTH: Adding new siding, especially siding with a 1/2 inch of insulation behind it, will result in significant energy savings.
FACT: New siding has very little insulation value in itself. Its only energy saving benefit is some tightening up of the home. Adding 1/2 inch of white beadboard to an uninsulated wall will save approximately $10-15 of natural gas per year per 1000 square feet of wall surface in conductive losses. Adding it to an already insulated wall will result in even less savings.
ATTIC:
- Weatherstrip attic access door.
- Insulate attic access door by attaching foam insulation or fiberglass batt to the back.
- Caulk electrical wire penetrations at the top of the interior walls and wires into ceiling fixtures.
- Seal around the plumbing stack(s).
- Seal around the chimney using a high temperature sealant such as muffler cement and metal flashing where necessary.
- Caulk along the tops of interior walls where the top plate meets the plaster or drywall.
- Seal all other holes between the heated space and the attic.
- Insulate the attic to R-40. If it is over R-30, go on to other items before adding additional insulation.
MAIN LEVEL:
- Install foam gaskets on all outlets and switches, even on interior walls, and use child safety plugs backed with gasket punch-outs to keep the cold air from coming in through the sockets.
- If you have a room air conditioner, remove it for the winter or seal it up and insulate it. Water heater insulation jackets can work well for covering the interior.
- Replace broken glass and loose putty on window glazing.
- Caulk around window and door woodwork, sealing where the frame meets the wall and all other joints in the window woodwork with a clear sealant.
- Seal around all ceiling fixtures, heat registers, medicine cabinet, bath tub, kitchen cabinets, drain and water pipes where they enter the wall in the kitchen and bath, and any other interior or exterior wall penetrations.
- If you have double hung windows with ropes and pulleys install pulley seals over the pulleys. The pulley seal fits around the rope and pulley and reduces air infiltration at that location.
- Weatherstrip windows and doors.
- Seal the top half of your double hung windows with a clear sealant after you've weatherstripped the middle section.
- Install plastic over inside of windows. If you desire something more permanent than plastic, install interior storm windows.
- Caulk along baseboard (including interior walls) with a clear sealant.
- Cut the ropes and remove the pulleys and install replacement window channels on double hung windows.
- Replace your old entry door with an insulated door.*
- Install an insulated window treatment.*
- Replace your old windows.* If you have a fireplace:
- Check to make sure damper is closing tightly.
- Install tight fitting glass doors and/or make a decorative insulated cover for it.
- Install a top sealing damper.
- Provide outside air for combustion.
BASEMENT:
- Seal the band joist and sill with caulk or foam sealant.
- Caulk around basement windows.
- Seal any holes in the foundation wall with caulk or foam sealant.
- Seal the hole where the bath tub drain comes down and any other plumbing or electrical penetrations into the basement ceiling with caulk or foam sealant.
- Insulate the band joist.
- If you have a crawl space, place a layer of plastic on the dirt floor, close any vents, and insulate the walls by hanging fiberglass batts down them and out two feet onto the floor.
- If you have a floor over an unheated space, such as a tucked-under garage, insulate the space between the floor and the garage to R-20 or greater. Insulate the basement one of the following ways: 1. Interior--build a 2x4 wall, insulate with batt insulation and cover with drywall or paneling. 2. Interior--use 2x2 furring strips with 1 1/2 inch rigid foam insulation between and cover with drywall. 3. Exterior--install extruded polystyrene or high density fiberglass down from the siding (protect the exposed portion) to one foot below grade (v) and then slope it out away from the house 2-3 feet. 4. Exterior--install extruded polystyrene or high density fiberglass down from the siding all the way down to the footings. This method would only be practical if you had to dig up your basement for other reasons, such as water problems.
EXTERIOR:
- Caulk around all penetrations such as electrical, telephone, cable, gas, dryer vents, water faucets, etc.
- Caulk around window and door frames.
- Caulk around storm windows where the metal meets the window frame if you have combination storms. If you have wooden storms that must be exchanged for screens in the summer, use rope caulk to seal around the storm.
- Install storm windows on all single-glazed windows.
- Install a storm door where you have none.
- If you have an exposed slab-on-grade, dig down a couple of feet and install extruded polystyrene down from the siding.
- If you are re-siding, consider adding 3/4" to 1 1/2" of rigid foam insulation and wrap the home with an air barrier (vapor permeable) material. Make sure the house walls are insulated before re-siding.
*The items marked with an asterisk (*) are, for the most part, only marginally cost effective and may be done for reasons other than energy savings.
