Home Energy Audit

As I wrote earlier, the Energy Star Home Energy Performance results told me that my home consumes more energy than most. The performance report lists four steps under Take Action:

1. Replace your 5 most frequently used lights…with ones that have earned the ENERGY STAR.
2. Look for ENERGY STAR products.
3. Heat and cool efficiently.
4. Seal up your home.

I started with the first item, but quickly skipped to the last one. After some reading, I felt that I was competent to find some leaks, do some sealing, and add insulation to my attics, but I knew that to get the best bang for my buck, I needed to enlist a professional for a home energy audit.

It was surprisingly difficult to find such a service. Many, many web sites advise calling one’s electric or gas utility, which I did to no avail. The Yellow Pages was equally unfulfilling. Google turned up very little, but I did find buried in a New York Times article a quote attributed to someone at an energy services company near me. I looked the company up through Google, called, and eagerly awaited the audit.

Based on what I had read, the audit process was largely what I expected. The auditor put a blower door in the doorway between my kitchen and garage, turned it on, then walked through the house with an infrared scanner to find places where warm air was being sucked in through cracks in my home’s structure. The results of this were surprising. Whereas I expected most leaks to be around doors, windows, and recessed lights, the biggest were

• through tongue-and-groove paneling on a gable wall to an attic space
• around fireplace stonework
• crawlspace walls
• along the joint where exposed beams meet a cathedral ceiling
• around some electrical outlets on external walls

Overall, the house tested as very leaky, with a blower leakage measurement of 5200 CFM(50).

The auditor also looked at the insulation in the three separate attics spaces (these are not connected because a portion of the house has cathedral ceilings) and the two crawlspaces (on each end of a partial basement). Insulation was good in the (ventilated) crawlspaces, relatively low in two of the attics spaces, and non-existent in the third attic space.

The auditor looked at my heater, water heater, and air conditioner, but did not look at my appliances. In other words, the focus was on heating and cooling, not whole house energy use.

Also, the auditor did not test the ducts. Based on the dryness of my crawlspaces, we decided to pursue making these conditioned spaces by sealing vents and any leaks along the rim joist. Therefore, all ductwork would be within conditioned space and all warm/cold air would stay within that envelope, rather than be wasted.

I now regret allowing him to skip the ductwork test. Based on heating performance last winter and the distribution of heat within my various rooms, I am convinced there is a duct leak near the blower. There is a space between a pair of floor joists that seems to get unnaturally warm (I can feel it through the basement ceiling and living room floor). I would like to confirm the problem and address it.

Following the auditor’s recommendation, I had professionals perform two types of insulation work. The simpler, and surprisingly more expensive, was to blow an additional six inches of cellulose into all three attic spaces. Because of some recessed lighting not rated IC (for insulation contact), they also built enclosures around the fixtures. That was done pretty poorly with drywall, duct tape and foam insulation. Aluminum sheeting rolled into a cylinder, as I have since seen on various web sites, would have been a more elegant solution.

The other insulation work was to spray icynene foam along the rim joists and over vents in the crawlspaces, and along gable walls in the attic spaces. The foam both insulations and plugs leaks. This job required some rework later, because a duct running close to the foundation wall in one crawlspace had inhibited a worker from getting the foam sprayed in the correct location.

For $400, the audit was definitely worthwhile. It helped prioritize the insulation and sealing that would be good for my house, the environment and my wallet.