A few notes on home energy use

This is our first post, and is intended to be informational. Please participate in the discussion on this thread on our discussion forum (after registering as a forum user). And of course, your blog post comments are always welcome.

A few months ago I did a project on work regarding various aspects of home energy efficiency, alternative forms of energy (like solar and wind), and some other areas of research like replacement windows, various kinds of insulation, and radiant barriers.

When looking for places in a typical home to save some money on energy, you have to first know where the typical home uses or loses a lot of power, so that’s where I started. Actually, the way you frame the question is very important. I got the questions “Where to home use the most power?”, “Where do homes lose the most power?”, “Where do homes lose the most heat?”, and “Where do homes leak the most AC?” These are all relevant, but slightly different questions needed to access the energy efficiency of a house.

This first pie chart, from the Florida Solar Energy Center, depicts typical heat gains in a home. This is good info for those of us in relatively hot states. I was surprised to see the amount of heat generated by appliances. Here in Texas, we tend to think of most of the heat coming from the roof/attic and the windows. But appliances like a refrigerator really crank out some heat. In an upcoming post I will examine the claims of massive savings made by radiant barrier companies, and this chart (as well as info from the Oak Ridge National Lab) will prove very important in evaluating those claims. But the fact that only around 22% of the heat gain comes from the attic in the first place immediately calls some of their claims into question.

Source: Florida Solar Energy Center

Next, we’ll look at a couple of pie charts on home energy usage, one from the U.S. Department of Energy, and one from Texas Electricity. These two organizations cut up the pie a bit differently, but they mostly agree. I think a lot of people would be surprised to know just how  much energy it takes to run a water heater. Keeping water hot 24 hours a day is an energy intensive endeavor.  It is my understanding that a good solar hot water system, if not too expensive, is the solar investment that is likely to pay for itself the fastest. We’ll look at that in the future too.

Source: U.S. Department of Energy
Source:  Texas Electricity

Finally, whether you are trying to heat or cool your home, air leaks will cost you money. This chart, from the Michigan Department of Environmental Quality, shows the typical sources of air leaks in a home. We live in an older home – built in 1960. There have been some very D.I.Y. changes made to the house over the years, and frankly, houses back then weren’t built that tight anyway. They are superior in many ways to new construction, but they need some tightening. These are all spots where you can get a lot of improvement. We have already replaced the crappy hollow door that went from the house into the garage with a good, tight-fitting steel door, and also lined that wall with good insulation (I got to tear down and then replace sheet rock), and you can really feel the difference. 

Source: Michigan Tech

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March 25, 2010 · Bob · One Comment
Tags:  Â· Posted in: Home Energy

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  1. Home Energy Use « Concrete Lunch - March 25, 2010

    [...] The first post, with some information on typical home energy use and waste is now up. Please check it out, and spread the word. I appreciate your support. [...]

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