Geothermal HVAC Myths Busted
1. Geothermal HVAC systems are not considered a renewable technology because they use electricity.
Fact: Geothermal HVAC systems use only one unit of electricity to move up to five units of cooling or heating from the earth to a building.
2. Photovoltaic and wind power are more favorable renewable technologies when compared to geothermal HVAC systems.
Fact: Geothermal HVAC systems remove four times more kilowatt-hours of consumption from the electrical grid per dollar spent than photovoltaic and wind power add to the electrical grid. Those other technologies can certainly play an important role, but geothermal HVAC is often the most cost effective way to reduce environmental impact of conditioning spaces.
3. Geothermal HVAC needs lots of yard or real estate in which to place the polyethylene piping earth loops.
Fact: Depending on the characteristics of the site, the earth loop may be buried vertically, meaning little above-ground surface is needed. Or, if there is an available aquifer that can be tapped into, only a few square feet of real estate are needed. Remember, the water is returned to the aquifer whence it came after passing over a heat exchanger, so it is not “used” or otherwise negatively impacted.
4. Geothermal HVAC heat pumps are noisy.
Fact: The systems run very quiet and there is no equipment outside to bother neighbors.
5. Geothermal systems eventually “wear out.”
Fact: Earth loops can last for generations. The heat-exchange equipment typically lasts decades, since it is protected indoors. When it does need to be replaced, the expense is much less than putting in an entire new geothermal system, since the loop or well is the most pricey to install. New technical guidelines eliminate the issue of thermal retention in the ground, so heat can be exchanged with it indefinitely. In the past, some improperly sized systems did overheat or overcool the ground over time, to the point that the system no longer had enough of a temperature gradient to function.
6. Geothermal HVAC systems only work in heating mode.
Fact: They work just as effectively in cooling and can be engineered to require no additional backup heat source if desired, although some customers decide that it is more cost effective to have a small backup system for just the coldest days if it means their loop can be smaller.
7. Geothermal HVAC systems cannot heat water, a pool, and a home at the same time.
Fact: Systems can be designed to handle multiple loads simultaneously.
8. Geothermal HVAC systems put refrigerant lines into the ground.
Fact: Most systems use only water in the loops or lines.
9. Geothermal HVAC systems use lots of water.
Fact: Geothermal systems actually consume no water. If an aquifer is used to exchange heat with the earth, all the water is returned to that same aquifer. In the past, there were some “pump and dump” operations that wasted the water after passing over the heat exchanger, but those are exceedingly rare now. When applied commercially, geothermal HVAC systems actually eliminate millions of gallons of water that would otherwise have been evaporated in cooling towers in traditional systems.
10. Geothermal HVAC technology is not financially feasible without federal and local tax incentives.
Fact: Federal and local incentives typically amount to between 30 and 60 percent of total geothermal system cost, which can often make the initial price of a system competitive with conventional equipment. Standard air-source HVAC systems cost around $3,000 per ton of heating or cooling capacity, during new construction (homes usually use between one and five tons). Geothermal HVAC systems start at about $5,000 per ton, and can go as high as $8,000 or $9,000 per ton. However, new installation practices are reducing costs, to the point where the price is getting closer to conventional systems under the right conditions.