Residential Energy Efficiency

With skyrocketing electric bills from the unusually hot summer and cold winter most of the nation is experiencing, there are plenty of "energy saving devices" on the market to help you "save money". You may encounter door to door salesmen, blind phone calls, or fliers in your mailbox or your email inbox. What saves money? How do some of them work? Do they work?

One of the first things to understand about cutting utilitiy cost is to understand how you get billed. As a residental customer, you get billed on the Kilo-watt hours used per billing cycle. This is then multiplied by your utilities rate, any additional charges are then added, and voila, you have a bill. Every month a meter man comes by and reads your meter, which tells them how much power you have consumed that month. Of course some meters now just dial that information in, but how they get the data isn't relevant. A kilo-watt hour is how much watts are used per hour. So, if all you run for a whole month is a 100Watt bulb, and it runs 24/7 for 30 days, you have used 72kW/hr and based on $0.10/kWh would owe $7.20. Now the actual consumption is different, since loads turn on and off all the time, and nothing is constant, but this is a general overview of utility billing and not an in depth dissertation. In 2008 the average US household used 920kWh. Utility cost vary based on region but $0.09/kWh would be a safe national average. Utility prices run from just under $100/month to well over $500/month based on the home, the weather and the price.

Watching ones bill jump from month to month can be frustrating. Some utilities allow a set rate based on a years average consumption, so your bill is always the same. Some months you would be paying more then you consume, some months less, but the beauty of the program is you can budget exactly every month instead of wondering if you need an extra $200 or so to cover the bill. Its this fear that some people play on. I have seen everything from a magic box that reduces energy use by 25% to magic hvac systems. Realistically lets be honest, if it sounds too good to be true, it probably is.

One of the most common used tactics is to show potential "customers" proof in residential statements from their "happy" customers. They will show a potential decline in utility bills from their install. There are several fallacies for this. This first is assuming that the weather was the same from year to year. I analyzed one such statement and found that the year they claimed was saving energy from installing their device, was a very mild year, while the previous year was a rather extreme weather year for that location. Weatherunderground.com has an excellent resource which displays heating degree days and cooling degree days. HDD and CDD are means of expression to indicate how far above or below average that day was based off a set temperature. In my study, the days tracked the utility bill almost exactly. So the high utility cost came from more need for heating or cooling. The year the device saved energy, was a much milder year, so the utility bill was much lower. This can be done on almost any one of their special demo's.

Granted there are some ways to save energy, but most have modest savings of between 5% and 9%. They will also show you a ROI or return on investment statement which shows when you will get your money's worth back from it. Take CFL replacement for an example(and this a very simple evaluation based on a simple scenario). For instance if you replace ten 100W incandescents with ten CFLs, you will save a little over 100kWH/month. Or if you look at it financially speaking, at $0.1/kWH you will save $1.24/month in utility bills. Now say based on an average price from a large retailer you can buy a 6 pack of CFL for $15. For simplicity lets say you can buy a 4 pack for $10 ($15/6*4). Thats $25 dollars in cost of the replacement CFL's. So at a savings of $1.24/month, it will take 20 months for you to get a return on your investment. A very simple scenario, based on simple numbers, but you get the idea.

Be careful when searching for energy savings devices, and if in doubt, consult your local utility. They have the resources to help make informed decisions.