Friday, March 28, 2008

Conservation, Efficiency, and Behavior: A Basic Analysis

Setting out to determine all the many ways of reducing one's household energy consumption is a daunting task. Our homes are constructed of complex, interlocking systems; the older our homes, the more mysterious they may seem. The many long lists of recommended improvements are general, not specific to one's own situation, and they are soooo long! Here is a simpler way to think about the project.
The two major organizing principles are ENERGY CONSERVATION and ENERGY EFFICIENCY. The third major impact is PERSONAL BEHAVIOR, because any systems in place are dependent to some degree on the way they are utilized. Individuals vary enormously in levels of commitment to decreasing their carbon footprint/energy use.

Energy Conservation refers to a home's temperature retention; in winter a home needs to be warmer than the outdoor temperature and in summer, cooler. All the home's surfaces - walls, windows, doors, ceiling, floor - together create the "home envelope". The tighter this envelope, the higher the level of conservation. Upgrades to the home's conserving abilities are generally one-time improvements which operate passively. Attic insulation, door sweeps, thermal pane windows, and the like help the envelope/barrier to retain winter's warmed air (heated by a furnace or boiler) and artificially cooled air in summer. In addition to infrastructure conservation upgrades (like tighter windows, wall and roof insulating, and air leak plugging), decorating choices can positively impact conservation. Insulated windows shades and curtains, insulating paint on walls, and thick carpets all help retain temperature, therefore consuming less energy to heat and cool. In winter, this translates to less gas or oil; in summer, less electricity. Conservation upgrades add to the comfort of your home, since they cut down on drafts and also on noise. In our local climate, it is our experience that with a better insulated home, one can get by with very little heating or cooling in spring and fall, our shoulder seasons.

Energy Efficiency refers to the amount of electricity required to run your appliances, devices, and lighting. In the old days of cheap electricity, this was rarely a concern. Over the past decade, government mandates for increased efficiency have resulted in significant efficiency improvements, allowing electronics to perform the same tasks using ever less energy. The goverment's EnergyStar rating is given to best-of-class products and covers most common household appliances. Of course increased efficiency can be offset by the proliferation of electronic devices and appliances present in an average household.
Older refrigerators, freezers, dehumidifiers are especially large consumers of electricity. Replacing them with newer models is recommended, especially since they run 24/7. Replacing old incandescent bulbs with "energy miser" CFL's is highly beneficial, more compelling since the aesthetics of CFL's have improved. With the rest of one's appliances, individual household use will vary enormously. (While replacing inefficient electrical appliances and lights with high efficiency models is a no-brainer, much of the electricity the average consumer uses is simply wasted because of personal habits of not turning out lights or turning off appliances. This is not, technically, an efficiency issue.)
It is important to note that in Pennsylvania, the vast majority of our electricity is generated by burning coal, the dirtiest of fossil fuels. Electricity generation needs to meet the maximum demand, hot summer days. Therefore even if you purchase wind power, it is still wise to increase your household energy efficiency to decrease overall demand, even if you personally are supplied by renewable energy.

Personal Behavior dictates how home energy is consumed, regardless of the level of energy conservation and efficiency. The homeowner determines the desired temperature and which appliances and devices are used. Programmable thermostats are a great technology, but are usually too difficult for average users to actually operate. Insulated curtains may be helpful, but only if you close them! When considering what upgrades to invest in, it is useful to also consider one's own personal style. Many systems can override human forgetfulness - programmable timers (that are simple to operate!), motion detector light switches which turn the lights off when not in use, and even remote thermostat controls. However, the average household will derive the biggest benefit from one-time passive improvements - the insulation in the attic just sits there, indefinitely, requiring no action or activity.
It is also important to consider that it is much cheaper to keep the people in the house warm, rather than heating all the air in the entire house. Treating yourself to high-quality thermal stockings and long-johns, buying a heated mattress pad, and adding a gas fireplace may go a lot further in making it comfortable to turn your thermostat down. Adding electric space heaters to the rooms you frequent, and leaving the others colder, is a common strategy. But all these activities will be ineffective if your heat is escaping through leaky windows and a poorly insulated roof. Hence the pyramid displayed: energy conservation is the highest priority, yielding the highest impact, in approaching the goal of reduced household energy consumption.


Bradley said...

When trying to save on your energy bill, the first place to look is at your windows. They are the weakest link in your home and are usually the main culprit for heat or energy loss.

If have old windows, chances are they are single pane and are not energy efficient. Make sure to upgrade to a dual pane window with low-e glass and argon gas between the glass.

Having worked with Jeld-Wen windows, I would highly recommend them as they are a certified manufacturer of energy star products and are backed by one of the most comprehensive warranties in the industry.

Condoor - Windows and Doors Vancouver has been installing energy star windows in the rough conditions of Canada for years without any problems.

Sally said...

hi, my name is Sally Newsome and I'm a distance learning student. I'm doing a presentation on energy wasting behaviour and would love to have your permission to use your pyramid diagramm as one of my powerpoint slides. Please could you email me if it's ok.
Many thanks
PS Great blog, but I must get back to work now!

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