HOW DO YOU BENEFIT FROM THE HIGHER EFFICIENCY SYSTEMS?
So you are wondering – should you pay a little more for those systems to take advantage of the high efficiency? The answer lies in the amount of time you expect to have the systems running. As you know, you will run them, likely, a few hours in the evening in the summer and fall. You might run them all night on low speed just for a breeze. So you should add up all the hours you might run the system in a year.
In Temecula, CA where I live I pay about 10 cents per kilowatt hour. A kilowatt hour is the measure of the number of watts you use up in an hour. As an example, if you use a hair dryer that is 1500 watts for 15 minutes (probably burn your hair), you use up 1/4 hour times 1500 watts or about 375 kilowatt hours. That would cost me about 3.75 pennies.
If you run your whole house fan for 3 hours each night at high speed for 6 months (the hot ones) you will use it for about 3 times 30 days times 6 months or about 540 hours. So now you have the data to really compare power savings.
FIRST, HOW MANY WATTS DO EACH TAKE?
Here is an analysis by Invisco of the top 3 rafter mounted suppliers. Clearly the EC motor is the best.