Five Percent: Conserve Energy

Climate Change Is Important: Energy Conservation is the First Step


May 19, 2009

Energy Audit: What We Learned

Category: Energy Audit,Household,Save Fuel,Take Actions,Tips – Tom Harrison – 12:27 pm

We recently had an energy audit for our house and learned a lot, including:

  • The most of the corners of the house were never insulated the first time
  • Our bulkhead door leaks like a sieve (maybe that’s why I can see light through it :-)
  • The attic door and whole house fan let in a lot of air
  • The chimney damper is pretty useless in terms of insulating
  • Air pours into our basement through the sill and old windows
  • Most of our windows still need to have caulking around the edges — air is getting in
  • All the leaks result in a complete air exchange about once every 70 minutes in winter

How the Audit Worked

There were two parts: a “blower door test” and an infrared camera inspection (the actual reports are linked below).

The blower door test basically is a way to create some suction of air out of the house with a sophisticated method of measuring air infiltration, or how well sealed your house it. One measure is air changes per house (ACH) — a house does need some fresh air from outside, but the target is something like 0.3 ACH — our house measured an average of 0.65 ACH, and in the winter when windy and colder the estimate is 0.87 ACH (about one change every hour and 10 minutes).

The blower door rig fits in the front door of your house, covering all but a hole sized for a special fan. The fan and some small air-tubes are hooked to a control unit, which runs the tests and measures how hard it has to pull to create a certain amount of vacuum in your house — the harder it has to work, the tighter your house. It runs for about 20 minutes at various settings, and sends the results to a computer when done.

ir-wind-bracesThe infrared camera can “see” heat and cold. Hot areas are red, cold are blue.

Our house was constructed around 1920 — in order that the house doesn’t move, all the corners have diagonal “wind braces” from floor to ceiling, in additional to the usual vertical wooden studs (when plywood sheathing replaced boards, wind braces became unnecessary). We had our house insulated with blown-in cellulose insulation several years back — they take off some of the siding, drill holes in the sheathing and pump the insulation in under pressure, one hole for each 16" stud bay. ir-normal-wind-bracesBut the insulators missed every exterior corner because the wind-bracing. This is very evident in the infrared picture.

If you look closely at the IR photo, you’ll also see that there are vertical lines in a lighter blue — these are the wooden studs in the wall, which shows that wood is not a good insulator.

The third part of the inspection was a walk-through while the blower was running. I could feel the draft blowing up from the basement as we walked down. Flemming, our auditor, used his IR camera to locate problem areas, then took an IR photo and a matching regular photo. He also had a can of “smoke” that he sprayed in certain areas so that I could see how much wind was blowing. When the fan was running, it produced almost 8 ACH (about 10x more than normal), but still, there was a lot of air flowing.

Part of the report calculated a potential savings of more than $300/year if all of the items are addressed properly.

I was properly motivated, to say the least.

How to Address the Findings

We have been given our marching orders on what to fix, and how. Some of the items any home owner could do, including:

  • Spray foam around the leaky sill in the basement
  • Caulk around windows
  • Seal other areas where cold air is leaking up from the basement
  • Improve weather-seal on our kitchen door
  • Buy a “Chimney Balloon” to block air-flow through the fireplace

There are other tasks that require carpentry or other specialized skills, including

  • Build a box to cover the whole-house fan in the winter
  • Build a cover for the attic stairs
  • Install a regular (exterior) door at the base of the stairs to the bulkhead door
  • Insulate the areas missed in the first round

I have a guy coming over this afternoon to do an estimate on the insulation (and maybe the other items). Cooler still, it turns our our fuel company, NationalGrid, is offering a 75% rebate on the cost of insulating, and there are some federal tax credits available, as well. Wow!

Here are the reports from our energy audit, from InfraredDiagnostics. They are both PDF files. Note, the IR file is 2.7MB.

8 Comments

  1. [Ed Note: The following was posted as a comment by a company that sells this stuff. But the article is right on, so here it is. Tom]

    How To Stop Drafts and Save On Energy Bills

    Imagine leaving a window open all winter long — the heat loss, cold drafts and wasted energy! If your home has a folding pull-down attic stair, a whole house fan, a fireplace or clothes dryer, that may be just what is occurring in your home every day.

    Drafts from these often overlooked holes waste energy and cost you big in the form of higher energy bills. Drafts are the largest source of heating and cooling loss in the home.

    Drafts occur through the small cracks around doors, windows, pipes, etc. Most homeowners are well aware of the benefits that caulk and weatherstripping provide to minimize energy loss and drafts.

    But what can you do about drafts from the four largest “holes” in your home — the folding attic stair, the whole house fan, 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 attic door. Try this yourself: at night, turn on the attic light and shut the attic stairway door — do you see any light coming through?

    If you do, heated and air-conditioned air is leaking out of these large gaps in your home 24-hours a day. This is like leaving a window or skylight open all year ‘round.

    An easy, low-cost solution to this problem is to add an insulated attic stair cover. An attic stair cover seals the stairs, stopping drafts and energy loss. Add the desired amount of insulation over the cover to restore the insulation removed from the ceiling.

    Whole House Fans and Air Conditioning Vents

    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 the drafty ceiling shutter between you and the outdoors.

    An easy, low-cost solution to this problem is to add a whole house fan shutter seal. Made from white textured flexible insulation, the shutter seal is installed over the ceiling shutter, secured with Velcro, and trimmed to fit. The shutter seal can also be used to seal and insulate air conditioning vents, and is easily removed when desired.

    Fireplaces

    Over 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 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 drafts and wasted energy caused by fireplaces.

    Why does a home with a fireplace have higher energy bills? Your chimney is an opening that leads directly outdoors — just like an open window. Even if the damper is shut, it is not airtight.

    Glass doors don’t stop the drafts either. The fireplace is like a giant straw sucking your expensive heated or air-conditioned air right out of your house!

    An easy, low-cost solution to this problem is to add a Fireplace Plug to your fireplace. Available from Battic Door, a company known for their energy conservation products, the Fireplace Plug is an inflatable pillow that seals the fireplace damper, eliminating drafts, odors, and noise. 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 drafts in through the duct, through your dryer and into your house.

    Dryer vents use a sheet-metal flapper to try to reduce these drafts. This is very primitive technology that does not provide a positive seal to stop the drafts. 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 drafts, and also keeps out pests, bees and rodents. 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.

    For more information on Battic Door’s energy conservation solutions and products for your home, visit http://www.batticdoor.com or, to request a free catalog, send a self-addressed stamped envelope to P.O. Box 15, Mansfield, MA 02048.

    ABOUT THE AUTHOR

    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 and an attic access door. Battic Door is the US distributor of the fireplace plug. To learn more visit http://www.batticdoor.com

    Comment by Battic Door — May 20, 2009 @ 5:43 am

  2. [...] Energy Audit: What We Learned [...]

    Pingback by 75% Credit for Insulating, from National Grid (Until July 31st) | Five Percent: Conserve a Little Energy — May 22, 2009 @ 5:40 pm

  3. [...] our recent energy audit found drafts in a number of places in our house, and even though the damper was closed, one of the biggest was [...]

    Pingback by Review: Chimney Balloon Saves Money, Conserve Energy, Simply | Five Percent: Conserve a Little Energy — July 25, 2009 @ 4:48 pm

  4. Tom, the info above by the commenter might have some merit, but wholly spamming your blog to post advertisments – Batman!
    Really though, lets share what has worked on our homes not shamelessly plug ourselves.
    BTW Tom, thanks for the tip on sealing up the basement windows. Im going to try that.

    Comment by TerryB — July 26, 2009 @ 9:38 pm

  5. [...] Fleming Lund, owner of Infrared Diagnostics did our energy audit — he came to my house on a sufficiently cold Spring morning and rendered the awful truth. Well, actually, he was very nice about it and said that our house was relatively tight and reasonably well insulated. But I know now, he was just being nice. [...]

    Pingback by I Believed I Was Conserving, Until I Looked at the Facts | Five Percent: Conserve a Little Energy — September 24, 2009 @ 4:16 pm

  6. [...] alike, it’s not surprising that more and more people want something done about it. From individuals doing what they can to big businesses calling for strong policies from world leaders, people are calling for action at [...]

    Pingback by Personal experience of climate change | Song for Jasmine — October 15, 2009 @ 2:56 pm

  7. [...] A while back, I had an energy audit and found that my house leaked like a sieve — a condition that left our efforts to insulate, replace windows, replace the gas burner and [...]

    Pingback by Step 2: Insulate, Step 1: Stop Drafts | Five Percent: Conserve Energy — December 6, 2010 @ 1:38 pm

  8. “blower door test” …very interesting!! thanks for sharing

    Comment by Vrata Beograd — March 13, 2012 @ 7:49 am

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