Image Credit: Claire P - Flickr
More Musings of an Energy Nerd
Owners of older homes often contact GBA and ask, “What can I do to make my home more energy-efficient?” My standard answer goes something like this: “The first step is to hire a certified rater to perform an energy audit of your home. The audit report will include a tailor-made list of retrofit measures to address your home’s specific problems.”
The advice is good, but it doesn’t do much to educate the questioner. Perhaps you are an intrepid homeowner who is willing to poke around your home’s nooks and crannies. Is there anything you can learn about your house without a blower door and an infrared camera?
Yes, of course there is. This article will explain the steps that homeowners can take to assess the condition of their house from an energy perspective.
Inspect the basement
If your house has a basement, that’s a good place to start your inspection. (If your house has a crawl space or an above-grade mechanical room, some of the advice in this section also applies to those areas.) The most important tool for this type of inspection is a powerful flashlight.
Check for air leaks. On a cold day, it’s fairly easy to locate basement air leaks; you may be able to feel infiltrating air with your bare hand. You may find that an incense stick is helpful in locating air leaks. Another way to locate air leaks is to turn off all of the lights in the basement and look for cracks of light. (This method only works during the daytime, of course.) Typical air leakage locations include the mudsill, around exterior doors, around windows, at utility penetrations, at pet doors, and at dryer vents.
Once you’ve identified where air is leaking into your house, you’ll have to…
Weekly Newsletter
Get building science and energy efficiency advice, plus special offers, in your inbox.
This article is only available to GBA Prime Members
Sign up for a free trial and get instant access to this article as well as GBA’s complete library of premium articles and construction details.
Start Free TrialAlready a member? Log in
11 Comments
Great summary - two minor additions
I would add an assessment of laundry - front load washers save lots of water, water heating energy (if warm or hot cycles are used) and drying energy via more effective final spin.
Also consider a brief search for phantom loads - use an advanced tactile thermal response sensor (palm of hand) to find things that run warm while "off" Those items, typically older media gear and chargers, should be put on a power strip or on a curb on collection day.
What?! Nothing about air conditioners?
I know you're in Vermont, Martin, but a lot of people in the US have air conditioners in addition to heating systems. Here are a few tips:
Similarly to looking at heating equipment, checking the age of the AC system can give you an idea of how soon you might need a new one. Some units will give the date of manufacture on the condensing unit (the noisemaker outside). If it's more than 10 years old, it's time to start saving for a replacement. If it's 15 years old, you're about to need a new one. I replaced our 24 year old AC a few years ago, but it was long past due. Here are 5 questions to ask when replacing your air conditioner.
Go outside and look at the condition of the condensing unit. If the fins are all bent up or filled with dirt, it needs to be cleaned. If it's got a lot of plants or other obstructions around it, clear some space for it. An AC condensing unit needs to breathe!
Check the filter. Dirty filters are a common problem that makes your system waste energy and not cool as well.
Get the AC serviced. If it's been more than a year, you need to get a pro to open up the system and do the regular maintenance, including checking the state of the evaporator coil and cleaning it if necessary. You don't want a sludge that kills, like this one had.
Here are some tips for getting better performance from your air conditioner that I wrote last year during the heat wave, when we set a record for high temperature in Atlanta.
In addition to the regular ductwork, don't forget to check the dryer vent. If it's clogged, it can burn your house down. Even if it doesn't do that, it can waste a lot of energy by making your dryer run longer to get the clothes dry. Here are some products that can help with dryer vents.
Response to Curt Kinder and Allison Bailes
Curt and Allison,
Great tips from both of you. Thanks for the additions.
Role of Fiberglass batts
What is the mechanism of fiberglass batt insulation causing mold on rim joists?
Response to David Beck
David,
Rim joists are cold during the winter, so you don't want to use an air-permeable insulation like fiberglass to insulate the interior of a rim joist. The insulation does nothing to stop the warm, humid interior air from contacting the cold rim joist.
When the warm, moist interior air contacts the cold rim joist, the moisture can condense (in the form of frost) or the joist can absorb moisture. Once the joist is damp, it will grow mold or begin to rot.
Acceptable insulation materials for insulating rim joists include rigid foam insulation and closed-cell spray polyurethane foam. If you use rectangles of rigid foam, remember to seal the perimeter of each piece of rigid foam with caulk or canned spray foam.
For more information, see The Best Way to Insulate a Rim Joist and Basement Insulation.
Rim joists
Is spray painting the joists an effective method of reducing mold and rot?
Response to David Beck
David Beck,
To avoid mold and rot, don't insulate with fiberglass. If you have fiberglass insulation on the interior side of your rim joists, paint won't prevent problems.
Remove the fiberglass and leave the rim joists uninsulated. Don't insulate the rim joists until they are dry. If you don't have time to insulate the rim joists correctly, it's better to leave them uninsulated than to insulate them with fiberglass. Once the rim joists are dry, insulate with rigid foam or closed-cell spray foam.
Rim joist and fiberglass batts
To preserve the heat in the house can I leave the batts cutting away 4-6" at the exterior ends?
Still another response to David Beck
David,
You are remarkably resistant to my advice. I've tried twice to point you in the right direction. At this point, all I can say is, "It's your house. You can do whatever you want."
3” termite inspection gap
If you are using CC spray foam for crawlspace rim and band joists as well as crawlspace wall insulation, how/where do you create the 3" inspection gap?
Response to Woody McMahon
Woody,
Regulations governing termite inspection gaps vary widely from one area to another, depending on local practices and the severity of the local termite problem. Your best source of information is your local building department.
If local regulations require a 3-inch-wide inspection strip, the usual practice is to omit the insulation at the top of the wall, so that you can see the top 3 inches of the concrete wall -- just bare concrete. Of course, following this practice incurs an energy penalty; but if the alternative is an infestation of termites, then the penalty is worth it.
Log in or become a member to post a comment.
Sign up Log in