Heating season is in full effect around here. It was very cold and windy last night. We had our first fire in the wood stove on Saturday and Sunday. I like having the wood stove going all day, the house really feels warm and comfortable. Something about having the radiant warmth of a fire that goes right through to the soul.
Something that I have not done yet this year is to check the house for air leaks through the thermal envelope. It sounds more complicated than it really is.
Basically, the thermal envelope is a fancy name for the system of insulation and seals that keep conditioned air from leaking out of the house. This includes the following things:
- Attic insulation
- Wall insulation
- Door seals, and weather striping
- Window seals and weather striping
- Seal between foundation and sill plate
- Miscellaneous seals around outlets, bathroom fans, ceiling lights, recessed light fixtures, dryer vents, etc.
Air leaks account for most of the heat loss in any structure. The higher up in the structure the leak is, the more warm air will escape outside and the more energy will be waisted. This is because of the stack effect that warm air inside a structure creates.
Since my house does not use force air for either heating or cooling, I do not have to worry about leaking air ducts and the job is a little bit simpler.
There are two ways to go about this, the first way is an examination of the seals, windows, insulation, etc. If the insulation has been in place for a few years, air leaks will be indicated by a darkened area. This is because dust and dirt get trapped in the insulation as the air rushes through it. Using a strong flash light, crawl around in the attic, checking around the bathroom ventilation fans, light fixture electrical boxes and other areas. Any leaks should be very evident.
Pay very close attention to the attic space, as most of the heat lost through this space. As much as possible, the insulation should be laid down as one continuous blanket with the vapor barrier intact and facing down. We used blown cellulose insulation which has settled since we put it in last year. I noticed that if formed its own sort of seal if undisturbed. The newer foam cellulose insulation is supposed to be very good.
Next, check the top seal on all the windows. The indication would be the same, dust and dirt in one area of the window seal.
Check all of the doors in a similar manner.
Another method is to wait until it gets cold out, then use a source of smoke, like a stick of burning incense. As it passed along the tops of the window seals, the smoke should rise straight up. If it goes sideways towards the window, there is an out draft along the window seal. Along the lower areas of the room such as the bottoms of doors and electrical outlets, the same test can be use, except you are watching for the smoke to blow into the room instead of rising straight up. If the smoke blows into a room, you have an in draft.
You can use the same method to check the seal around the foundation and sill plate. Be careful with the burning incense. I know we have a problem around the foundation sill plate under the kitchen. In some spots, I can see light shining through the crack, which is not a good sign. I have put some thin foam insulation in the cracks as best I could, but it needs a permanent fix.
Sealing up the leaks
I used a can of Great Stuff foam to seal up around the bathroom ventilation fan and the dryer vent. That is where I noticed some dirt and discolored insulation. The other thing that I will do is build an insulated box using 1 inch rigid foam board and construction adhesive to put over the stair hatch into the attic.There was weather stripping around the hatch, but I think this was mostly ineffective and a lot of heat was being lost though that hole.
The electrical outlets that are located in outside walls have foam seals between the outlet covers and the wall. This is effective for sealing those openings.
The windows and doors all look good. The basement is another story. It is a bit of unglamorous work crawling around in the attic and basement, but, if done correctly can save a significant amount of money on the heating (and cooling) bill.
Popularity: 4% [?]
subscribe
How To Reduce Your Heating Bills This Winter / Energy Conservation Begins at Home
Imagine leaving a window open all winter long — the heat loss, cold drafts and wasted energy! If your home has a folding attic stair, a whole house fan or AC Return, a fireplace or a clothes dryer, that may be just what is occurring in your home every day.
These often overlooked sources of heat loss and air leakage can cause heat to pour out and the cold outside air to rush in — costing you higher heating bills.
Air leaks are the largest source of heating and cooling loss in the home. Air leaks occur through the small cracks around doors, windows, pipes, etc. Most homeowners are well aware of the benefits caulk and weatherstripping provide to minimize heat loss and cold drafts.
But what can you do about the four largest “holes” in your home — the folding attic stair, the whole house fan or AC return, the fireplace, and the clothes dryer? Here are some tips and techniques that can easily, quickly and inexpensively seal and insulate these holes.
Attic Stairs
When attic stairs are installed, a large hole (approximately 10 square feet) is created in your ceiling. The ceiling and insulation that were there have to be removed, leaving only a thin, unsealed, sheet of plywood.
Your attic space is ventilated directly to the outdoors. In the winter, the attic space can be very cold, and in the summer it can be very hot. And what is separating your conditioned house from your unconditioned attic? That thin sheet of plywood.
Often a gap can be observed around the perimeter of the door. Try this yourself: at night, turn on the attic light and shut the attic stairway door — do you see any light coming through? These are gaps add up to a large opening where your heated/cooled air leaks out 24 hours a day. This is like leaving a window open all year round.
An easy, low-cost solution to this problem is to add an attic stair cover. An attic stair cover provides an air seal, reducing the air leaks. Add the desired amount of insulation over the cover to restore the insulation removed from the ceiling.
Whole House Fans and AC Returns
Much like attic stairs above, when whole house fans are installed, a large hole (up to 16 square feet or larger) is created in your ceiling. The ceiling and insulation that were there have to be removed, leaving only leaky ceiling shutter between the house and the outdoors.
An easy, low-cost solution to this problem is to add a whole house fan cover. Installed from the attic side, the whole house fan cover is invisible. Cover the fan to reduce heating and air-conditioning loss, remove it when use of the fan is desired.
If attic access is inconvenient, or for AC returns, a ceiling shutter cover is another option for reducing heat loss through the ceiling shutter and AC return. Made from R-8, textured, thin, white flexible insulation, and installed from the house side over the ceiling shutter with Velcro, a whole house fan shutter cover is easily installed and removed.
Fireplaces
Sixty-five percent, or approximately 100 million homes, in North America are constructed with wood or gas burning fireplaces. Unfortunately there are negative side effects that the fireplace brings to a home especially during the winter home-heating season. Fireplaces are energy losers.
Researchers have studied this to determine the amount of heat loss through a fireplace, and the results are amazing. One research study showed that an open damper on an unused fireplace in a well-insulated house can raise overall heating-energy consumption by 30 percent.
A recent study showed that for many consumers, their heating bills may be more than $500 higher per winter due to the air leakage and wasted energy caused by fireplaces.
Why does a home with a fireplace have higher heating bills? Hot air rises. Your heated air leaks out any exit it can find, and when warm heated air is drawn out of your home, cold outside air is drawn in to make up for it. The fireplace is like a giant straw sucking the heated air from your house.
An easy, low-cost solution to this problem is to add a fireplace draftstopper. Available from Battic Door, a company known for their energy conservation products, a fireplace draftstopper is an inflatable pillow that seals the damper, eliminating any air leaks. The pillow is removed whenever the fireplace is used, then reinserted after.
Clothes Dryer Exhaust Ducts
In many homes, the room with the clothes dryer is the coldest room in the house. Your clothes dryer is connected to an exhaust duct that is open to the outdoors. In the winter, cold air leaks in through the duct, through your dryer and into your house.
Dryer vents use a sheet-metal flapper to try to reduce this air leakage. This is very primitive technology that does not provide a positive seal to stop the air leakage. Compounding the problem is that over time, lint clogs the flapper valve causing it to stay open.
An easy, low-cost solution to this problem is to add a dryer vent seal. This will reduce unwanted air infiltration, and keep out pests, bees and rodents as well. The vent will remain closed unless the dryer is in use. When the dryer is in use, a floating shuttle rises to allow warm air, lint and moisture to escape.
If your home has a folding attic stair, a whole house fan, an AC return, a fireplace, and/or a clothes dryer, you can easily, quickly and inexpensively seal and insulate these holes.
Mark D. Tyrol is a Professional Engineer specializing in cause and origin of construction defects. He developed several residential energy conservation products including an attic stair cover, an attic access door, and is the U.S. distributor of the fireplace draftstopper.