Category — windows

Dear Mr. Energy,

What will give me the best return on my money: replacing my single-pane windows with double-pane low-e windows, replacing my traditional hot water heater with a solar hot water heater, or sealing my attic and adding more insulation?

–Perplexed in Pittsboro

Dear Perplexed,

Mr. Energy loves a no-brainer. For, neighbor friend, this is one of the easiest questions he’s had in a long time. Of these three possible home improvements the answer is obvious: seal your attic and add insulation. The reason it’s so obvious is in the math – sealing your attic and adding insulation is the cheapest fix of these three (even if you add in the cost of a home energy audit to help you pinpoint your air leaks) and will garner you the most in energy savings over time. The return on your investment is high.

The other two options will absolutely save you money and energy in the long run, but they cost a lot more, which means a much longer pay-off. We’re talking decades (even with tax credits and energy company rebates) as opposed to just a year or two for the attic sealing and insulation combo.

Your question has allowed me to get on my soapbox. Please indulge me for a moment. Here it is: companies that install windows or solar hot water heaters have done a marvelous job convincing the public that the best things homeowners can do is to buy their products. Marvelous.

It is absolutely true that new windows are more energy-efficient than old, and solar hot water heaters do save money when compared to the costs of heating water using traditional hot water heaters. But – dear readers – do not believe any company that promises a pay-off in a few short years for these two items. Do the math yourself. Base it on your own energy bills, energy use, and actual cost of installation.  Once you do this you’ll realize that if your goal is to save the most energy for the least cost, there are more immediate and cost-effective solutions.

Dear Mr. Energy,

Last year I had an energy audit, just like you always suggest, and I made several of the improvements my auditor suggested. I’m not seeing the results that I thought I’d see. What gives? Why aren’t I saving more money on my energy bills?

–Disgruntled in Durham

Dear Disgruntled,

First, let me express my sincere apologies that you are not seeing better results from the weatherization you’ve done on your home. In our experience, an energy audit and follow-up weatherization generally can save a homeowner 20-30% on his or her energy bills, depending on what’s been done. It’s distressing that you’re not seeing the results you want.

That said, there are a number of reasons why you might not be seeing that 20-30% drop. First, check to be sure you’re comparing apples to apples. Are you looking at the same month’s worth of bills from previous years? Was the weather comparable in that month? In central North Carolina we have variable weather; this past December was a much colder month than December of the previous year. Along those lines, have energy prices gone up this past billing cycle? In Mr. Energy’s house, propane went up by a good 40 cents per gallon. This made our bill go up while our energy use hadn’t.

If you’ve adjusted your expectations because of increasing costs or because of weather changes, another possibility could be the “Snackwell effect.” Remember when fat free cookies first hit the market? People went crazy and ate as many cookies as they wanted, thinking that since they were fat free they wouldn’t make them gain weight. Then – blammo – people gained weight because although the cookies were free of fat, they sure weren’t free of calories or sugar. This scenario can be applied to energy-efficiency, too. If you’ve made energy efficiency upgrades you may have gotten more lax with your energy habits, as well. In Mr. Energy’s house we upped our thermostat by a degree this winter, for example…and we are paying for it. Perhaps you’ve decided to take advantage of your snugger house and made your surroundings more comfortable. Just because your home is tighter doesn’t mean that you can use more energy and not pay for it.

Along these same lines, you may have purchased a new or bigger appliance that is sucking up more energy than your old one. A large flat-screen uses more energy than older, smaller TVs. And if you didn’t replace your smaller TV, but simply moved it to another room to make room for the new, big TV, you’ve doubled your TVs – doubling your energy use. Energy Star appliances are more energy efficient than non-Energy Star appliances, but more of anything = more money spent on energy.

Another lifestyle possibility is that in your effort to save money you may be staying home more than in years past. Staying at home more means that heating and cooling systems are on more, your television is on more, you are cooking more, and you are using all other appliances more. This can add up.

And finally, look at the report your auditor gave you. Did you do everything on it – particularly the items on the list related to your duct work, attic, and crawl space? Have you kept up with yearly HVAC tune-ups? If you had major energy updgrades done, like new ductwork or insulation, did you ask the auditor to come back to do a post-test of your house? It may be worth asking your auditor back to ensure that the installers did a good job.

In a previous blog post I wrote an explanation of how replacing your windows was not the smartest way to spend your energy efficiency budget. Green Building Advisor, a wonderful, comprehensive website on all things green-building related, has published an article that backs me up on it.

Here’s what they say:

Window replacement isn’t the best place to start in energy upgrades. When planning energy improvements to an existing house, replacing windows should show up toward the bottom of the list. It almost always makes sense to improve an existing home’s air tightness and add insulation to the attic and basement. Replacing an old furnace or refrigerator can also be cost-effective. But if the windows work well, it’s usually best to put replacing windows lower on the list. In a cold climate, the best way to improve single-glazed windows is to install exterior storm windows with low-e glass.

Now, note that they don’t say that windows don’t matter at all. In new construction it’s very important to consider types of windows as well as installation methods for energy efficiency. But they are saying that replacing existing windows, even replacing single-pane windows with double, low-e windows, does not pay off in the long run. There are better ways to spend your money.

Whenever I tell people that my husband and I own a company that specializes in energy efficiency, they almost always respond by telling me about their home’s windows. Either they’ve just replaced their windows and so they think they’ve done all they can do, or they are saving up for window replacement because they’re convinced that’s the most important thing they can do to make their homes more energy efficient.

The problem is that most of the time, replacing windows gives homeowners a very poor return on their investment. They’re simply not a cost-effective way to increase a home’s energy efficiency.

I know you don’t believe me! No one ever does…but consider the math:

According to the article, “Embracing Energy Efficiency,” in the Oct/Nov. 2007 issue of Old House Journal (the original article can be found here; this information is from a sidebar in the article), if you have a home with older windows – windows that measure 3′ by 5′, are single pane, and functioning, the breakdown for replacement is as follows:

Scenario 1: Storm windows over single-pane original windows.

Cost: $50/window

Energy savings: 522,218 Btu/year

Annual savings/window: $13.20 (assuming gas heat at $1.09/therm – this rate may vary)

Payback time: 4.5 years

Scenario 2: Double-pane replacement of single pane window

Cost: $450/window

Energy savings: 625,922 Btu

Annual savings/window: $11.07

Payback time: 40.5 years

Scenario 3: Low-e glass double-pane thermal replacement of single-pane window

Cost: $550/window

Energy savings: 902.772 Btu

Annual savings/window: $16.10

Payback time: 34 years

Scenario 4: Low-e glass double-pane thermal replacement of single-pane window with storm window

Energy savings: 132407 Btu

Annual savings/window: $2.29

Payback time: 240 years

Believe me now? It’s not your windows, folks. And even if you do worry that air is leaking out of your single pane windows, the solution is not to replace them, it’s to install storm windows. And please, don’t get me started on how foolish it is to replace double pane windows…or how tragic it is to take out historic windows! But that’s the subject of another post.

So if it’s not your windows, what is making your home so energy inefficient?

Click here to find out.

(image by foreverfrida via flickr.com)