Posts from — August 2009

Here’s a great blog post that outlines exactly why homeowners should get energy audits. Basically, the writer explains that an energy audit will tell you where you should spend your money to get the most energy efficiency improvements for your dollar. An energy auditor operates independently  - if you don’t need new windows, or a new HVAC system, or new insulation – the auditor won’t tell you you do because he/she isn’t making their living by selling those things. The auditor is making his/her living by performing audits.

My family’s business does both audits and the subsequent weatherization. Because we can and do perform the fixes that we recommend, we are very careful to separate the two parts of the job. When we perform an audit on a home we tell the homeowner that we are available to bid on the repairs, but we encourage the homeowner to get other bids as well. This is not a business model that all energy audit/weatherization companies follow, however. Many companies offer a free audit as a way to get people to buy their weatherization work. Apparently this works well for them, but if I were a homeowner working with a company operating under that model I’d wonder if the repairs they advised I purchase really would help my home’s energy efficiency, or if they were just trying to sell me something. If they sell me too many services or repairs, the money saved by the “free” audit isn’t money saved at all.

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)