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A Few Simple Facts About Gas And Electric Heating Systems
By Phillip Rye and Doug Rye

To make your home more energy efficient, you need to understand the energy efficiency of different types of heating and cooling systems. Many times people are confused by inaccurate information they receive from manufacturers and sellers of heating and cooling equipment. But all you need to know in order to make wise decisions when purchasing this equipment are a few simple facts.

First of all, the proper sizing of equipment is of utmost importance for comfort and low utility bills. Once the proper size is known, then you must decide what type of system best suits your needs. Let's look at three ways houses are heated.

Natural gas furnace,
Air-to-air electric heat pump,
Geothermal heat pump (electricity).

Now, let's consider how efficient they are. And when I talk about heating efficiency, I'm talking about how efficiently the system converts either natural gas or electricity to heat for you home.

A typical gas furnace will be rated at about 80 percent efficiency when it is new and if it is installed properly. That percentage will lessen with each year's use. An 80-percent efficiency rating means that 80 percent of the gas used will provide heat and the other 20 percent goes up the flue. For example, look at your neighbor's gas flue on a cold winter morning and see the steam coming out.

While I don't recommend this, a gas furnace that is 90-percent efficient can be used. With this unit, about 10 percent of the fuel goes up the flue. At first glance, you might think 80 to 90 percent sounds pretty good. But consider this. Would you purchase gasoline for your car and pump 10 to 20 percent of it on the ground? In my opinion, our nation would not have to worry about shortages of natural gas if we simply didn't waste it.

Another popular type of heating system, an air-to-air heat pump, uses electricity instead of gas. All Doug Rye homes use electric heating systems. An air-to-air heat pump, properly installed, would operate at an efficiency of around 250 percent. I know what you are thinking. �How can anything be more than 100 percent energy efficient?�

Remember, we are talking about how efficiently a unit uses either electricity or gas to move or create heat. Unlike a gas-fired furnace, a heat pump does not actually create heat, it simply moves heat from one location to another. Air-to-air pumps extract the heat from the air. With a heat pump, you use one unit of electricity and get about 2.5 units of heat.

My favorite system, the geothermal heat pump, is simply the very best there is. Most geothermal heating systems operate at close to 400 percent energy efficiency! Wow!

That's five times the efficiency of the 80 percent gas furnace. As this heat pump is extracting heat from Mother Earth, which is a constant 57 degrees, it is operating on minimal stress and using a very small amount of electricity to move the heat from the earth into the house.

With a geothermal system, you buy one unit of electricity (one unit of heat) and Mother Earth will give you three more units of heat for free. (That three units of heat is solar energy that Mr. Sunshine gave us over millions of years.) In future columns, we'll talk more about how air-to-air and geothermal heat pumps work.

Doug Rye is a nationally recognized energy consultant and licensed architect. Doug also host the "Home Remedies" radio talk show that is broadcast in 15 states.

Phillip Rye is a licensed engineer and has spent the past 15 years studying energy efficiency and energy conservation.

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