June 10, 2010

Electric Utility Energy Audit Program

When we bought our house last spring we talked to the oil company that served the previous owner and found that they had used 1100 gallons of heating oil every year! Given oil prices in recent years that was not something that we looked forward to.

Our state's utilities collect a fee every month to fund conservation programs. One of these programs provides reduced price energy audits for home owners. In our case, for $75 a private energy audit company came out to our house and put our place through the wringer.

The main analysis was via a blower door test. The test involves using a computer controlled fan that is set up in the main doorway. The fan pulls a vacuum on the house and backs out how much air is infiltrating the structure. Air infiltration is the biggest energy waste in most homes. It is also the easiest to correct.

Once the amount of air infiltration is known, it is compared to what is "normal" for a well sealed house of equivalent size. The interesting thing to note with this is that the right value is NOT zero. In fact, the residual value was relatively high, this is to ensure healthy indoor air quality through sufficient air changes.

The air infiltration is then reduced through caulking, weather stripping, and sealing performed right then and there by the audit team. In our case, a couple of door sweeps, sealing off a few access panels and caulking entry/exit points of pipes & cables got us a decent amount of reduction, but we were still a good ways from "world class". On a hunch, the crew installed a removable plastic sheet over the whole house fan vent. That was the key, and dropped the value down to near perfect.

I had hoped the auditors would have addressed the window sealing. I am not convinced they are all that well sealed, but in the end, the overall house infiltration value was about as low as it could go within the recommended levels.

If performed during colder weather, many of the audit companies will also photograph the house through a thermal camera. Our audit was performed in early fall, so the outside temperature did not cooperate.

On top of the sealing and testing, up to 25 CFL light bulbs were offered as replacements in existing internal light fixtures. We were able to take advantage of 22 or 23 of these. The replacements were all 60 watt equivalent, which for single bulb fixtures just isn't enough in my opinion. But they are fine for multi-bulb fixtures.

Lastly, they left us with a Kill-a-Watt device for measuring the power usage of any plug in device. This allows you to determine exactly how much electricity a particular device uses.

I highly recommend to any home owner to investigate the conservation programs offered by their utility companies. There's no downside, but plenty of smaller energy bills to be gained.

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