Bingo!
I found a wonderful summary of federal tax incentives available to homeowners that choose to make energy efficiency upgrades. This is courtesy of the U.S. EPA's Energy Star program.
Thursday, April 9, 2009
Tuesday, April 7, 2009
Home Energy Audits: The Infrared Advantage
It's fair to say that this house has more than its share of air leaks. The real challenge is to prioritize. That's where the infrared imagery from the energy audit comes in handy. Big leaks come before the little ones. Infrared (IR) imagery helps to put an order of magnitude on these opportunities.
In this case, we're looking at the floor in the dining room where a bay window bump-out extends from the north face of the house. This is an overhang; you can actually go outside and stand beneath this area:
One task for me is to remove the shoe molding and fill behind with caulk or expandable "foam in a can." The other task is to remove the external planking beneath this and install insulation. Given the space available, that insulation will probably be one-inch thick rigid board.
In this case, we're looking at the floor in the dining room where a bay window bump-out extends from the north face of the house. This is an overhang; you can actually go outside and stand beneath this area:
One task for me is to remove the shoe molding and fill behind with caulk or expandable "foam in a can." The other task is to remove the external planking beneath this and install insulation. Given the space available, that insulation will probably be one-inch thick rigid board.
Friday, April 3, 2009
Energy Audits: Revealing Your Home's "Second Price Tag"
The province of Ontario is currently considering a bill that makes energy audits a legal prerequisite to the sale of a home. As you might suspect, this is generating some spirited debate. But the argument brings light to a little recognized fact: a house has two price tags. Here's what I mean:
1. There's the price indicated in the traditional settlement transaction that passes the property title from one owner to the next.
2. There's the present value of all inputs that the house will require for proper upkeep. This covers everything from repairs and maintenance to-- you guessed it-- utility consumption. The new owner will be obligated to make these outlays for as long as he or she owns the property.
The idea here is that a proper energy audit is a window on a property's future energy liabilities. Ideally, the report should show how the house's energy consumption compares to structures of similar size, configuration, appliance profile, etc. Such a comparison requires an analysis of the utility bill history for the property; an inventory and diagnosis of heating, ventilation, and air conditioning systems; and an evaluation of leaks in the building shell.
You can't predict future energy prices. But you can use a recent annual utility bill history for comparison to average home data. This is a reasonable way to get a relative measure of the "second price tag" that prospective buyers should consider when purchasing a home.
1. There's the price indicated in the traditional settlement transaction that passes the property title from one owner to the next.
2. There's the present value of all inputs that the house will require for proper upkeep. This covers everything from repairs and maintenance to-- you guessed it-- utility consumption. The new owner will be obligated to make these outlays for as long as he or she owns the property.
The idea here is that a proper energy audit is a window on a property's future energy liabilities. Ideally, the report should show how the house's energy consumption compares to structures of similar size, configuration, appliance profile, etc. Such a comparison requires an analysis of the utility bill history for the property; an inventory and diagnosis of heating, ventilation, and air conditioning systems; and an evaluation of leaks in the building shell.
You can't predict future energy prices. But you can use a recent annual utility bill history for comparison to average home data. This is a reasonable way to get a relative measure of the "second price tag" that prospective buyers should consider when purchasing a home.
Thursday, April 2, 2009
Energy Star Home Energy Yardstick
There are a LOT of Internet-based, do-it-yourself tools for calculating home energy use. The grand-daddy of these sites is The U.S. Environmental Agency's Energy Star platform.
The "Home Energy Yardstick" is typical of free, online resources. This tool allows you to compare your home's energy consumption to national averages. So, since I already maintain a spreadsheet with my historical utility bill data, it was a fairly simple task to enter a handful of numbers like the house's square footage, zip code, annual consumption and expenditure figures for gas and electricity, and so on.
With the press of the "enter" button, my results emerge: a humbling 5.9 on a scale of 1 to 10, where 10 is "most efficient." The screen also provides a list of prescribed improvements, with links to explanatory pages elsewhere in the Energy Star archive.
Note that national averages are based on other homeowners' self-reported data, which may or may not be correctly entered. However wobbly the data, it's better than nothing. By investigating this alternative route, I find the same leading recommendation: seal the air leaks and improve insulation. The only way to improve this tool is to provide an estimation of dollar savings-- but that result is obviously dependent on the specific improvements that the homeowner elects to make. To be fair, the model can't measure what has yet to be done.
The "Home Energy Yardstick" is typical of free, online resources. This tool allows you to compare your home's energy consumption to national averages. So, since I already maintain a spreadsheet with my historical utility bill data, it was a fairly simple task to enter a handful of numbers like the house's square footage, zip code, annual consumption and expenditure figures for gas and electricity, and so on.
With the press of the "enter" button, my results emerge: a humbling 5.9 on a scale of 1 to 10, where 10 is "most efficient." The screen also provides a list of prescribed improvements, with links to explanatory pages elsewhere in the Energy Star archive.
Note that national averages are based on other homeowners' self-reported data, which may or may not be correctly entered. However wobbly the data, it's better than nothing. By investigating this alternative route, I find the same leading recommendation: seal the air leaks and improve insulation. The only way to improve this tool is to provide an estimation of dollar savings-- but that result is obviously dependent on the specific improvements that the homeowner elects to make. To be fair, the model can't measure what has yet to be done.
The Blower Door Test
The critical part of our home energy audit was the blower door test. In so many words, this is a diagnostic that measures how much the house leaks. "Leakiness" is crucial for quantifying energy waste. This is not a question of eliminating air infiltration, but instead optimizing it. The house needs to breathe, especially so that excess water vapor can escape. If it doesn't, you develop mold problems. At the other extreme, if too much air escapes, your furnace and air conditioner have to run longer to compensate-- driving up your utility bill in the process.
The blower door test puts a physical measure on air flow in and out of the house. To conduct this test, the audit technician sets up an apparatus like the one shown in the picture:
The key component is a high-power electric fan that essentially sucks air out of the house. To conduct this test, all other doors and windows are closed, and all house fans plus the clothes dryer are turned on. The remaining gaps and penetrations are then the collective "pathway" for air infiltration. Gauges on the blower door apparatus indicate the volume of air movement, measured in cubic feet per minute (CFM). The data generated by these gauges are compared to engineering standards for how much air should infiltrate a house of a given square footage.
The results for us: A house of our size should be "breathing" at a rate of 1,800 CFM. The blower door test shows that the current rate is like 5,300 CFM-- three times what it should be. Before this test, I had only a vague understanding of my home's heat loss. My understanding now has an order of magnitude-- which is my motivation to do something about it.
Only one word of caution: the blower door test moves a SERIOUS volume of air. Nothing in the house was disturbed or damaged. But I will say that it effectively pulls dust out of every imaginable recess, like from the interior spaces between walls. Don't be surprised if the house has develops a musty odor for this reason. Fortunately, it dissipates after half a day or so.
The number-one item on my summer improvement list is to seal air leaks. We'll discuss that exercise in future posts.
The blower door test puts a physical measure on air flow in and out of the house. To conduct this test, the audit technician sets up an apparatus like the one shown in the picture:
The key component is a high-power electric fan that essentially sucks air out of the house. To conduct this test, all other doors and windows are closed, and all house fans plus the clothes dryer are turned on. The remaining gaps and penetrations are then the collective "pathway" for air infiltration. Gauges on the blower door apparatus indicate the volume of air movement, measured in cubic feet per minute (CFM). The data generated by these gauges are compared to engineering standards for how much air should infiltrate a house of a given square footage.The results for us: A house of our size should be "breathing" at a rate of 1,800 CFM. The blower door test shows that the current rate is like 5,300 CFM-- three times what it should be. Before this test, I had only a vague understanding of my home's heat loss. My understanding now has an order of magnitude-- which is my motivation to do something about it.
Only one word of caution: the blower door test moves a SERIOUS volume of air. Nothing in the house was disturbed or damaged. But I will say that it effectively pulls dust out of every imaginable recess, like from the interior spaces between walls. Don't be surprised if the house has develops a musty odor for this reason. Fortunately, it dissipates after half a day or so.
The number-one item on my summer improvement list is to seal air leaks. We'll discuss that exercise in future posts.
Wednesday, April 1, 2009
The Drafty Door Issue
A few years ago, we remodeled the kitchen. I decided at the time to replace the old kitchen door that provides access to the back yard. I thought I was being frugal in merely replacing the slab (i.e. the "door" panel itself) while leaving behind the jamb and related trim.
Bad choice. I got the new slab to fit, but it was a chore and the results weren't great. Subsequent weather stripping was only a partial solution. Consequence: we experienced some ferocious drafts around the door, especially on the coldest of winter days. LESSON LEARNED: install pre-hung doors! They are manufactured to provide a snug, weather-sealed fit.
Bad choice. I got the new slab to fit, but it was a chore and the results weren't great. Subsequent weather stripping was only a partial solution. Consequence: we experienced some ferocious drafts around the door, especially on the coldest of winter days. LESSON LEARNED: install pre-hung doors! They are manufactured to provide a snug, weather-sealed fit.
Our energy audit confirmed what I already new to be true: this calls for a retrofit. This will be a do-it-yourself job for later this summer when the weather gets warmer. I expect to pay about $250 for materials.
"Free" Home Energy Audits
I'm not sure why, exactly, but a lot of people expect energy audits to be gratis, free of charge. Lo and behold, there are a couple forms of "free" energy audits available to homeowners: those provided by utility companies, and those provided by vendors of certain home improvement products. If you were to investigate, here's what you'd find out:
Utility-provided energy audits. This service is often provided in response to consumer complaints about rising energy bills. It's a good idea, but think about it: how many resources can a company put into a service that generates no revenue? Despite the best of intentions, a "free" energy audit purposely cuts corners to produce what is often a simple, generic checklist. Not much in the way of cost-benefit analysis specific to YOUR situation.
Vendor-supplied energy audits. Let's put is this way: If you get an energy audit from a company that installs windows, don't be surprised if their report concludes that your best option for saving money is to buy new windows.
That leaves you with the option of actually paying for an energy audit. This means making an outlay for the time and expertise that it takes to thoroughly diagnose your home's building envelope and appliance functionality. It means paying for a report that provides a cost-benefit analysis of specific improvements for your home.
Utility-provided energy audits. This service is often provided in response to consumer complaints about rising energy bills. It's a good idea, but think about it: how many resources can a company put into a service that generates no revenue? Despite the best of intentions, a "free" energy audit purposely cuts corners to produce what is often a simple, generic checklist. Not much in the way of cost-benefit analysis specific to YOUR situation.
Vendor-supplied energy audits. Let's put is this way: If you get an energy audit from a company that installs windows, don't be surprised if their report concludes that your best option for saving money is to buy new windows.
That leaves you with the option of actually paying for an energy audit. This means making an outlay for the time and expertise that it takes to thoroughly diagnose your home's building envelope and appliance functionality. It means paying for a report that provides a cost-benefit analysis of specific improvements for your home.
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