Questions You Should Ask
About
A New Geothermal
Heating System
1. What is the BTU size of the furnace that's being proposed? Furnaces are designed to provide specific amounts of heat energy per hour. The term "BTUH" refers to how much heat can be produced by the unit in an hour. Before you can determine what size furnace you will need, you must have a heat loss/heat gain calculation done on the structure. From that, an accurate determination can be made on the size of the heating system you will need. Most fossil fuel furnaces are substantially oversized for heating requirements, resulting in increased operating cost.
2. Is the efficiency rating actual or just a manufacturer's average All types of heating and cooling systems have a rated efficiency. Fossil fuel furnaces have a percentage efficiency rating. Natural gas, propane and fuel oil furnaces have efficiency ratings based on laboratory conditions. To get an accurate installed efficiency rating, factors such as flue gas heat losses, cycling losses caused by oversizing, blower fan electrical usage, etc., must be included.
Geothermal heat pumps, as well as all other types of heat pumps, have efficiencies rated according to their coefficient of performance or COP. It's a scientific way of determining how much energy the system produces versus how much it uses.
Most geothermal heat pump systems have COPs of 2.5 - 3.5. That means for every one unit of energy used to power the system, two and one-half to three and one-half units are supplied as heat. Where a fossil fuel furnace may be 50-90 per cent efficient, a geothermal heat pump is about 300 per cent efficient. Some geothermal heat pump manufacturers and electric utilities use computers to accurately determine the operating efficiency of a system for your home or building.
3. Will minimum entering water temperature have an affect on which heat pump I buy? Yes. If you have an open-loop system, your entering water temperatures (EWTs) may range from the 70s in the southern United States to the 40s in Canada. All heat pumps can handle temperatures in the moderate to warm ranges. A closed loop system, on the other hand, will encounter EWTs below freezing. Not all geothermal heat pumps will operate efficiently at those temperatures. It is important for you to know what EWTs your heat pump will handle.
4. Are the dealer and loop installers qualified? Do not be afraid to ask for references from dealers. A reputable dealer will not hesitate to give you names and numbers to call to confirm his capabilities. The same applies to the loop installer.
5. Will open- or closed-loop be best for me? That depends on several factors as stated earlier. A dealer should be willing to install what is best for you, not for him.
6. How long is the payback period for your geothermal heat pump system? To figure this accurately, you must know how much per year you will save in energy costs with a geothermal system and the difference in costs between it and the alternative heating system and central air conditioner.
To calculate your return on investment (payback in number of years), divide the annual savings into the additional cost. When you install a geothermal system in a new home, the monthly savings in operating costs will generally offset the additional monthly cost in the mortgage, resulting in a monthly positive cash flow immediately. Keep in mind that energy savings is only one of the many benefits you receive from a geothermal system.
7. If a home has ceiling cable heat or baseboard heat, do air ducts need to be installed? Not always. It may be desirable to install geothermal heat pump room units. For some small homes, one room unit would provide most of the heating and cooling needs. Ceiling cable or baseboard units could then be used for supplemental heat.
8. If I want to know more about geothermal heat pumps, whom should I contact? Your electric utility. Most electric utilities have information about these systems. If you have a question they cannot answer, they will put you in contact with someone who can.
