How much air is your house leaking? Are you unknowingly slurping in dirty air from your garage and attic? Perhaps a blower door test can help you find out. Tom White is the Publisher of Home Energy (aka "my boss"). He's gotten to know a lot about home performance in this job over the last few years. He knows about blower doors and pressure envelopes, duct blasters and thermal envelopes; and has been initiated into the knowledge that you never use duct tape on ducts. But there was one more initiation to go. So he went to the Web to find someone to do an energy audit on his house.

"I went to the ServiceMagic Web site that I learned about editing a Home Energy article," says Tom. "Within less than a minute after I entered some basic information about my house and what I was looking for in the way of an energy audit, the phone rang." It was Sustainable Spaces, a home performance contractor located in San Francisco. Tom made an appointment for his audit for the next week. "They were offering a 'Stimulus Special' for $395."

The house Tom shares with his partner Dmitri was built in 1907. "The home has never been remodeled," says Tom. "We recently had the furnace replaced with a hot water radiant system. We have been careful to keep to the original features of the home, so we got our radiators from buildings built around the same time that used to be part of the heating systems in buildings at Fort Baker." They also installed a renewable energy source. "We installed photovoltaic (PV) panels on our roof, but we should have had the audit first to show us how to use less energy and save on the PV.  Our annual true-up statement says we owe $75 for electricity, but I want to get that down to $0!"

Rob Mitchell, an experienced contractor who knows a lot about Bay Area houses, came with two younger men for an audit of Tom and Dmitri's 102-year-old home. The crew closed all the exterior doors and windows, installed a "blower door" in the main doorframe, and depressurized the house. Immediately, dust and insulation particles began to pour through the "pocket doors" from the attic. After taking some measurements to get a general sense of how leaky the house is, and blocking some of the major air leaks, the crew from Sustainable Spaces then pressurized the house. "We walked around the house with a liquid pencil, which showed there is airflow around switch plates, gaps in the baseboard where the home is connected to the outside, and the cabinet in our kitchen where there used to be 'torpedo tubes,' which used to hold hot water heated by the wood stove, and other places" says Tom.

So the old house has some problems with air leakage, which means heating energy being lost to the outside. The crew also found out that the humidity in the kitchen was 20% higher than that on the outside of the house. "We both took showers that morning, and I had a cup of hot tea," says Tom. That was enough to keep the humidity high a few hours later.

Since the home has no mechanical ventilation, moisture build up could lead to mold growth on surfaces in the living spaces, or-even worse because it is hidden-within the walls. Mold can degrade building materials and create poor indoor air quality. Tom has allergies and a moldy house could make it difficult for him to breathe. Since Tom is living in the mild climate of the Bay Area, where we can open windows and get fresh air other ways in our leaky houses, the moisture may not hang around long enough to be a problem. If he lived in a cold climate such as Minnesota's, or a hot-humid climate such as Atlanta's, fixing the air leaks in his house without adding mechanical ventilation could create a "sick house", meaning one with poor indoor air quality due to mold.

"We won't get the report until next week," says Tom. The report will include specific numbers for air leakage from the house to the outside-or in this case between the living spaces and the attic and basement. Too much air flow means lost energy and too little means a sick house. The report will also give a range of measures that will make Tom and Dmitri's house healthier and more energy efficient. "We'll decide what measures we want done when we get the report. We made our heating system more efficient with the radiant system that heats the living spaces and provides us with hot water. We use half the gas now to heat water than we did before. So spending a lot more on fixing the building envelope doesn't make so much sense to us right now. We'll probably fix the big leaks by air sealing around the attic. And we may insulate under the floor between the living spaces and the basement."

"I wanted to have our house audited mostly because I'm curious," says Tom. "And we want to save energy." But from now on when Tom talks about home performance, and the importance of healthy and efficient homes, it will take on a whole new dimension-the homeowner's perspective.

The CCHT twin house facility in Ottawa, CanadaTwo weeks ago in this blog I tried to answer the question, Do compact fluorescent lights (CFLs) save energy overall? Even though CFLs contribute a lot less heat to a house in the winter, compared to incandescents, CFLs still save energy overall, even in places like Anchorage, Alaska. Thanks to the folks at the Canada Centre for Housing Technology (CCHT) who did the research to answer that question.

The Department of Energy, the Environmental Protection Agency, and others recommend that we set our thermostats at 68°F in the winter and 78°F in the summer. Some people are comfortable at home with these temperatures and some or not. So how can we save energy and still be comfortable?

Besides recommending that people replace their incandescent bulbs with CFLs, we at Home Energy also encourage people to turn their thermostats down when they are away from home during the winter, and to set them up when they are away from home in the summer. Both actions are supposed to save energy. But do they? It's not really that clear. For example, if you set your thermostat at 60°F before you leave for work in the morning, and then set it at 68°F in the afternoon when you get back, does your furnace use more energy raising the temperature of your house from 60°F to 68°F, than it saves by having the temperature at 60°F all day?

Once again the Canadians have come up with an answer. Marianne Armstrong and her colleagues at CCHT used the twin house research facility to show that thermostat set backs in the winter and thermostat set forwards in the summer really do save energy.

In the research house where they set the thermostat back to 64°F at night and during work hours, from 72°F, it saved more than 10% on heating costs compared to the house that was set at 77°F all day and night. A 61°F setback saved more than 13%.

In the summer, a set forward to 77°F at night and during work hours from 72°F saved 11% on cooling costs. Now for the big winner: Setting the thermostat up to 75°F all day and all night saved 23% of cooling costs compared to the house set at 72°F. That's a savings of about 8% for every degree adjustment.

If you lower your thermostat a few degrees when you are away from home this winter, or when you are asleep, you'll save energy and money. If you set your thermostat up a few degrees when you are away from home or asleep this Indian Summer, you'll save energy and money. And you won't be uncomfortable.

Here are three of the DWHR devices tested, showing the
headers: Left to right, the Retherm S3-60, GFX G3-60,
and PowerPipe S3-60. Credit: Charles ZaloumI don't think there is one big solution to our energy problems and the environmental problems related to the use of fossil fuels–there are lots of little solutions that in the end add up to a big solution.One of those little solutions I have been reading a lot about lately is a Drain Water Heat Recovery Device (DWHR). It looks like part of something you would find hidden in the hills and hollows of Appalachia that makes moonshine, but a DWHR device is a simple copper coil that you put around your shower drain that recovers some of the heat from your shower water. Cold water is circulated through the coils, gets heated by the drain water, and then flows into your hot water tank, or into your shower and hot water tank.The device is simple, effective, and doesn’t require much (like, no) maintenance. Drain water heat recovery devices contribute to large energy savings in laundries and in multifamily buildings, but will also work very well in single-family homes–as long as there is room under the showers. My one-story house in Walnut Creek is not a good candidate for such a device.

The simple workings of a drain water heat recovery device.
Credit: gfxstar.ca, Inventroment Energy Solutions.Canadian researchers from Natural Resources Canada tested the effectiveness of several DWHR devices at the Canadian Centre for Housing Technology. For an Ottawa household in which four people each take 12 minutes showers every day, a DWHR will save $150 a year in energy costs (at present, Canadian dollars are about equivalent to U.S. dollars). That's about three times as much energy saved as the energy used to run an energy-efficient 20-cubic-foot refrigerator for a year. Over the 30-year lifetime of the DHWR, which costs about $800 including installation, the device will save the household close to $3,000.The Canadian researchers created a Web-based Drain Water Heat Recovery-Energy Savings Calculator where building contractors, plumbers, and homeowners can go to estimate the cost effectiveness of several DWHR devices on the market. You just need to know the model of the device, the temperature of your shower water, estimated shower times, and so on. Right now it is set to work for Canadian locations. For U.S. homeowners, you have to pick a city in Canada. The calculator will be updated as newer technology is developed and tested.

Here are some Web sites where you can find out more about DWHR devices that were submitted for testing at the Canadian Centre for Housing Technology:

• Power Pipe www.renewability.com
• ECO-GFX www.gfxstar.ca
• Retherm www.retherm.com

If a million households in the United States installed DWHR devices, we’d save a collective $150 million in annual energy costs, or about the equivalent of 1.25-billion kWh of electricity–or a ginormous amount of carbon dioxide in air from the natural gas not burned and electricity not generated.

Jim Gunshinan is Managing Editor of Home Energy Magazine. He holds an M.S. in Bioengineering from Pennsylvania State University, State College, Pennsylvania, and a Master of Divinity (MDiv) degree from University of Notre Dame.