What to Expect from a Home Energy Audit

When I bought a Victorian two-flat in 2006, I was charmed by its oak trim, tall ceilings, bay windows, and classic Chicago shotgun-style layout. I shrugged at the ancient furnaces and drafty windows—feh! These windows are original, baby! 

After two frigid winters, however, I could no longer ignore the fact that I was paying almost $300 a month to keep my charming vintage apartment at a drafty, uneven 63°. And my tenants, though I bought them a brand-new, high-efficiency furnace, still paid over $200 to keep their place only slightly warmer.

I was determined to address the problem, but where to begin? The place had 100-year-old windows, no insulation, leaky ductwork, and a drafty attic. New windows seemed an obvious but outrageously expensive step. I suspected that insulating the attic would help, but how? Should I pour loose fill under the floor? Staple fiberglass batting to the roof? I had visions of struggling with enormous bats of itchy pink fiberglass in a sweltering attic only to find that I’d done it wrong. And what if the furnace broke down in January? Was I really prepared to make the best choice in replacing it? I was reluctant to spend so money and effort without being sure that I was doing the right thing.

I decided to make an appointment with the aforementioned Informed Energy Decisions, a home energy auditor. I spoke with Cappy Kidd, the owner, who promised to investigate the place from top to bottom and provide me with detailed recommendations, listed in order of importance. By the end, he said, I’d have a long-term energy-reduction plan to undertake step-by-step as I could afford to do it. I was psyched.

Based on the square footage of my home and the fact that I have two furnaces (one for me and one for the tenants), they charged me $750. With just one furnace it would have been $600; an audit for a single-family house runs somewhat less, depending on the size.

The audit took place on a hot day in August. Inspectors Cheryl Pomeroy and Aaron Lund showed up at 10:00 a.m. with a carload of equipment. They loaded everything in and sat down with me at the dining room table to find out my concerns and describe their process. After chatting for awhile, they got to work.

Step 1: The Heat-Seeking Camera
The infrared camera (which looks like a television camera) can detect the difference between heat and cold; it is used to look for insulation gaps in walls. This test is actually much more useful in wintertime when the contrast between outside and inside temperatures is pronounced; the camera can see the gap in the insulation because that is where the temperature of the wall is much lower. In summertime, you can’t see much because the walls are pretty uniformly warm. However, you can see the heat left by your hand after you touch the wall, which is kind of cool.

For me this test was a moot point, since I don’t have any insulation except in my kitchen and bedroom, where I insulated the outside walls with fiberglass during a renovation.

Step 2: The Blower-Door Test
Cheryl and I went around the house and closed all of the doors and windows in both apartments, including the storms. The idea is to replicate wintertime conditions, when you seal the house as tightly as possible. In the mean time, Aaron set about installing a tremendous contraption in the front door involving a large fan, red canvas, some thin plastic tubing and a digital meter called a manometer, which measures pressure. The contraption is called a blower-door; it sucks air out of the house and measures the rate at which the air leaves. The higher the air flow, the draftier your house.

After we had the place closed up, Aaron turned on the fan (it was loud) and took the reading. Cheryl performed a set of calculations and told me that under average conditions (i.e., not unusually windy), my house exchanges 100% of its air every hour. That means that the furnace has to heat the entire house all over again every 60 minutes. Was that a lot? Ideally, she said, it should take three hours for a complete air exchange. In other words, my house is three times as drafty as it should be.

I wasn’t surprised.

Step 3: The Smoking Gun
It took a lot of imagination to think that six months from now these drafts, so welcome in August, would be turning my toes numb. So it goes. As I walked through the house, I found powerful drafts in some unexpected places. By the windows, no surprise. From my back door, which opened to a three-season porch (let's say two-and-half), I felt a wind that practically knocked me down. I knew the kitchen was drafty, but jeez. I'd had no idea. But strangest of all was the breeze that emanated from around my dishwasher. After scratching my head a minute I realized that when installing the dishwasher, my carpenter had probably not closed up the drywall behind it, leaving a hole wide open into the plumbing chases and creating a huge draft from the attic and basement. Who knew?

Cheryl pulled out a smoke wand (available at your neighborhood magic shop) and held it up to every place likely to reveal a draft. Some of the worst culprits were the heating vents. Before you think, "duh, of course there's air coming through the vents!" realize that this is not the air that's supposed to be coming through the vents, but the air that leaks through the rough openings where the ducts are hooked up to the floor or ceiling. In winter, this would not be the warm air from the furnace, but the cold air from the attic or basement, getting sucked in through the gaps.

We cased the entire building this way, leaving a piece of blue masking tape to indicate each of the drafts so that I could go back later to seal them up. Other problem spots: windows (naturally), the bases of walls (along the quarter-round), electrical outlets and the bases of light fixtures. The first- and second-floor apartments yielded similar results. The basement showed a few holes to the outside, large but easily filled, as well as extra vents cut into the ductwork, suggesting that someone had once lived in the basement and diverted some of the heat from the first floor. That explained a lot: my tenants were heating the basement as well as their own apartment!

(Another odd thing in the basement was that the main heating duct was covered with aluminum foil. What the heck??? Aaron was very diplomatic: "Ahm, just so you know, foil is a poor insulator.")

Troublesome as these discoveries were, they were few enough and easily remedied. The attic, on the other hand, was a bit of a mess. Holes, gaps everywhere! The balloon frame, shown at right, left an open channel in the walls from top to bottom, so that any crack in a wall downstairs would open into the walls and up into the frosty attic. Even the two walls with fiberglass batting were unsealed, since the open fibers allow air to travel vertically.

The attic floor was full of holes, as was the ductwork. And the plumbing chases were wide open. It was suddenly clear to me that all that air around the dishwasher was being sucked from a big hole in the attic floor, as shown below. (This also gave me some insight into how rodents travel through a building.)

Step 4: The Prescription

After leaving bits of blue tape all over the house, Cheryl and Aaron returned to the dining room to write up their findings and recommendations. It took at least an hour, which is to say they were very thorough. They filled out a Window Survey, an Air Sealing Survey, an Energy Condition Summary and then a two-page Action Plan, which listed three major priorities:

1. Air-seal and insulate attic.

2. Insulate outside walls.

3. After house is fully sealed and insulated, replace worst windows as budget permits with double- or triple-pane thermal windows.

Beyond that was a list of smaller projects including tankless water heaters, weather stripping, etc.

Imagine my delight at being told that I did not have to run out and spend $20,000 on new windows!  Cheryl was quite emphatic that the windows were far from my biggest problem: my attic was performing like a great big chimney, creating a draft through which all of my warm, expensive, fossil-fuel-burning and carbon-dioxide–producing air was flying into the sky. If I covered my windows with plastic like I do every winter, they'd do a perfectly good job until I could afford to replace them.

When I expressed my gratitude at this news, Aaron nodded and said, "If we save you from buying one window you don't need, you've paid for the audit right there."

We spent quite awhile talking about strategies for insulating the attic, which I will discuss in further posts. Finally, they packed their gear into their little four-door sedan (without an inch to spare) and were off on their way.

I ran back upstairs and pored over the literature they had left me and the reports they had prepared in such loving detail. I couldn't wait to call the insulators.

 

Comments

[Clayton]

Great blog and a great post! I'm curious now what an energy audit would find in my place. I don't have an attic, and I do have all new windows (except one) but that idea about sealing up the house and sucking the air out with a big fan makes a lot of sense. I wonder if (not to take business away from Informed Energy Decisions) the person without $750 could do something similar? I have a huge window exhaust fan that I could see doing the same thing. How about this: sealing up my house and running the big window exhaust fan, and going around with a stick of incense to all the windows, doors, cabinets, etc to see where the air is coming in? (bonus: my house would smell good).

[Zoe Zolbrod]

Angela, have you taken any steps towards dealing with the hole near your dishwasher? We have a similar situation in our kitchen--a cool, cool breeze blowing in all winter long between the sink and the dishwasher--but we don't know how to patch the hole without ripping out cabinets.

[Patti Vick]

Hi Angela-Great Blog!!
So, how have you noticed a difference in your heating costs this winter? Are your toes cold or warm?
You rock!

[Joe Derhake]

This is a great story how you can find the low hanging fruit in the world of energy conservation. I bet Aaron and Cheryl's surveys would be of great value in commercial energy audits.

[Angela Bowman]

In response to Zoe re. the dishwasher; I have yet to close up the wall behind the dishwasher. It was my hope that by sealing off the plumbing chases, i.e. the holes at the top (attic) and bottom (basement) of that wall, it would cut the draft off at the source. I can't say for sure how much of a draft is still coming through.

Eventually I should seal the hole regardless, which is not as difficult in my case because (a) I can pull the dishwasher out and (b) the cabinet next to it is the sink cabinet, which is open to the wall in back anyway.

You might consider looking in the attic and basement and see where the draft is coming from. If you find it, fill it with rockwool or spray foam. More to come on air sealing in a coming post.

[Angela Bowman]

In response to Joe: Informed Energy does indeed to a lot of commercial energy audits, for which there seems to be a growing market.

[Angela Bowman]

In response to Patti: my toes are warmer! More on that to come.

[Julia]

Hi Angie - what a beautiful blog! I'm going to send it to my class. We are in the throws of analyzing data from 170 homes in Minneapolis where my tireless and awesome students have surveyed homeowners about what they have done to make their homes more efficient, and why they might care to do so...Once we've figured out the story that the numbers tell I'll post some goodies. Looks like our lives are merging once again.

Julia

[jeffrey]

Thanks for starting nest. It will prove to be interesting. For some reason
one of your posts caused me to look at bit into tankless water heaters vs
tank type. Tankless are the rage now, and like many things that are a rage,
there is sometimes more marketing than science involved.

In floor heating systems are an example. Lots of talk about how they are
more efficient than "normal" heating systems. I read a study (I can't
remember now who published it, but it seemed to be someone neutral) where an
in floor system and forced air system was installed in the same building.
Turned out that the in floor system energy savings was not substantiated.
There are lots of variables, however, so ymmv

I came across this article: http://tinyurl.com/5na8px about tankless vs
tank water heaters. the study was conducted by a manufacturer of both types of water heaters.

Two things stood out: that they are sensitive to hard water. The tankless
mentioned, lost efficiency within two weeks of hard water usage. Water
softeners can be used, but if it breaks down for a week or two and you are
forced to use water unsoftened then you've done damage to the tankless.

The other is that the energy savings with tankless came with infrequent use (eg, a single person, only using water in morning and evening) whereas for larger water usage, ( eg family) it looks like the amount of savings isn't that great, compared to cost of installation. Plus, the tankless are finicky about installation, needing special venting, air intake, gas supply, and location. So if you use water infrequently, and energy is expensive, and have proper location and venting situation, tankless might make sense.
Again, lots of variables.

[Cappy Kidd, President Informed Energy Decisions]

I want to thank Jeffrey for his contribution to the discussion regarding tank or tankless water heaters. It is true this is an issue we are often asked about.While the performance and maintenance issues will vary depending on manufacturer, There is another part of the equation that should be uppermost in our thinking. When we think of preservation of scarce natural resources, we should draw an = sign between energy and atmosphere and water. Already today not some time in the future close to two billion people are in a water scarcity situation. This is not just limited to the third world, for instance Australia. One thing that studies show is that people with tankless water heaters take longer showers since they don't run out of hot water. There is a wonderful organization called the Alliance for Water Efficiency that focuses on the broad spectrum of water issues. Their website is allianceforwaterefficiency.org

[jeffrey]

i came across another piece about tankless hot water heaters.
http://tinyurl.com/a4ac3

really, i am not campaigning against them. i find the argument interesting, and the pros and cons applicable to other possible strategies that people are apt to employ.