Our energy audit

Our energy kitWe’re actually doing reasonably well in terms of electrical usage and heat. According to Vectren, we’re using about 77% of the natural gas that other similar houses in the area are using. Since only about 5% of that is for cooking, our primary difference has to be heating. During the day, we keep the thermostat at 66. If I didn’t work from home, we could go cooler, but that’s about as low as I can be comfortable for long periods of time. We used to go down to 59 at night, but Maggie read that a difference of more than 4-5 degrees overtaxes the furnace, so we changed it to 61. I think that you could warm the house in stages to avoid that problem as well, but it turns out that with a gas furnace it’s not as large an issue.

Even though we’re doing pretty well heating-wise, we wanted to make sure that the house doesn’t have any major issues. There have been a lot of improvements since the late 1960s! The local Duke Energy provides a free service called Home Energy House Call, where a technician comes through and examines your house for energy problems. Maggie’s parents had to wait months for their appointment, so we signed up last week and got ready to wait. Luckily, a slot opened up yesterday, so Maggie and I got our energy audit remarkably quickly!

The beginning of the audit consisted of a series of basic questions. How big is the house? How old is it? How many people live here? After that came energy-specific ones. Do you use CFLs? Do you wash your clothes in cold water? I’d guess that most people who get an energy audit answer yes to these, since they’re aware and interested in energy conservation.

Once we had those out of the way, the auditor inspected the house, including the crawl space. He felt along the windows and external outlets for drafts. The bedroom windows were really drafty, which we knew, so he suggested using “great stuff” insulating foam. He also checked the windows themselves, but most of ours are double-paned, which was fine. He looked around external doors for gaps around the edges for weatherstripping, but only found a little piece on one of the back doors.

More importantly, he said that around here, our attic should be insulated to R38, which is about 10 inches of blown insulation. We only have about 6, so that’s a big issue. Heat rises, so a poorly insulated attic is killer in the winter. The auditor suggested that we use cellulose rather than fiberglass. It insulates about 50% better, which means we wouldn’t have to add as much. For either, we can rent a blower and buy bags of insulation and do the job ourselves, so it’s a relatively cheap project. We also need to insulate the panel that leads to the attic, since right now it’s not insulated at all.

After doing the inside, we headed outside to get into the crawlspace. Unfortunately, I sustained a back injury in the line of duty from slipping down our icy steps. My sore back is a reminder that we need to de-ice our steps as well as insulate our attic.

Perilous as it was, the trip to the crawlspace as worthwhile, since it was the worst offender on the tour. Although our ducts are insulated, nothing else in the crawlspace is. Even worse, our vents are still open so we’re basically sitting on an ice box. The crawlspace under the addition, which is where my office is, is properly insulated although the vents are still open.

Our home inspector had told us to insulate the crawlspace when we could, but we’ve heard conflicting things about how exactly to do it. According to our auditor, we should put down plastic sheeting and insulate the walls, but not bother to insulate the floors. During the summer, we can keep the vents open to prevent moisture problems but in the winter, that’s not an issue. When the weather gets cold, we should close the vents and put insulation behind them and reverse the process when it gets warm.

In addition to these tips, our auditor left us with some weatherstripping, a low-flow showerhead, a faucet aerator, some light switch and outlet insulating pads, and some CFLs. Over all, not a bad return for half an hour of our time!

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5 Responses so far »

  1. 1

    Emily said,

    January 8, 2009 @ 12:08 pm

    Where did you read about “overtaxing the furnace”? I’ve been wrestling with this question myself – but my house guru said that you won’t really see any difference in heat savings unless you go down at least 5 degrees for at least 8 hours.

  2. 2

    Maggie said,

    January 9, 2009 @ 5:35 pm

    So, a friend who had an energy audit done a couple months ago said her energy auditor told her not to change the thermostat more than 5 degrees at night because it uses a bunch of energy when it kicks back on in the morning. I asked our auditor and he said he’d heard that but believes it’s only when you’re talking about a really large house and/or a heat pump that has to work really hard to generate heat. He said with the size of our house (~1300 sq ft) and our gas furnace, we would be fine turning it way down at night.

    I’ll confess, I’ve turned it up a bit for the puppies. They’re really pathetic when they shiver. 🙂

  3. 3

    Reader Poll: Home Improvement | GreenCouple.com said,

    January 12, 2009 @ 10:34 pm

    […] and dreaming about all the exciting projects I could work on in 2009.  We recently had our home energy audit, which generated a list of projects.  I also have some coupons for seeds and plants to improve the […]

  4. 4

    Green tax refund? | GreenCouple.com said,

    April 1, 2009 @ 11:28 pm

    […] of blowing the money all on one thing, we could split it among multiple projects. After the energy audit, the most obvious thing to do is improve the insulation in our attic and crawlspace. Insulating the […]

  5. 5

    Kent said,

    July 13, 2010 @ 11:02 pm

    Your friend may have a heat pump with electric back up. When the temperature is very cold the electric back up (very expensive) will have to run more because the heat pump will not be able to generate enough heat from the outside air so it would be more expensive to swing the temperature on a heat pump electric back up system. Heat pump with gas forced air back up swing the temperature as much as you want for savings. Stictly forced air swing the temp, you will save but it will take longer to be more comfortable. The gas forced air runs more efficient in a longer heating cycle, just takes longer to be comfortable.

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