If you’re looking for more ways to go green, geothermal energy might be worth considering. Geothermal energy is the process by which heat is harnessed from below the earth’s surface, then used to heat or cool your home. According to the U.S. Department of Energy, geothermal energy is one of the best ways to get clean, renewable energy. Of course, there are pros and cons. This article looks at what those are, so you can decide if geothermal energy may be right for you.
Geothermal Energy – The Pros
Geothermal energy is currently the most energy efficient system available because it uses the power of the Earth itself to heat and cool your home. It emits no gasses and produces no significant pollution because it harnesses heat energy that already exists in the Earth, rather than creating new energy. A geothermal system does, however, require a small amount of electricity to run.
Low Operating Costs
The groundwater heat pump systems that harness geothermal energy cost less to operate than even the most efficient natural gas HVAC systems available today. Geothermal “is currently the most energy efficient system to heat a home,” according to our resident energy expert, Keith Hill, technical support manager for Minnesota Air.
Those low costs get even lower if you operate your system using an off-peak power program. “Groundwater heat pump systems, when installed on an off-peak electrical power system, have extremely low operating costs,” Keith explains. “Off-peak power is a program available through your electric utility that provides you with half-price electricity for your heat pump. In return, you give permission for the utility to shut off your heat pump system during peak demand. That typically happens only for small periods of time during subzero days or hot summer days.”
Keith recommends that if you do operate a geothermal system on an off-peak program, you’ll probably want to have a backup furnace for peak winter periods when the power company may turn off your pump.
Reliable Temperature Control
Geothermal energy is stable and reliable because the Earth’s temperature doesn’t vary, staying in the 50 to 60-degree range all year.
“Even during our arctic winters, the frost sets only so far, 4 to 6 feet in most parts of Minnesota. But go further down, and the soil temps are much warmer and very constant,” Keith says. “Using the stable Earth temperature as a heat sink enables groundwater source heat pumps to be extremely efficient both capturing heat and rejecting heat during the cooling mode.”
Not only does geothermal have a small carbon footprint, but it has a pretty small land footprint, too. Since the majority of the system is doing the work underground, the above-ground portion takes up far less space than you’d imagine. That fact is what makes it work with smaller houses and big commercial buildings alike.
Real Renewable Energy
Geothermal is renewable… really renewable. Because you’re using the Earth itself for energy, as long as the planet keeps spinning, geothermal energy will continue to be available. According to the Department of Energy, we have an “almost unlimited amount of heat generated by the Earth's core. Even in geothermal areas dependent on a reservoir of hot water, the volume taken out can be re-injected, making it a sustainable energy source.”
Geothermal Energy – The Cons
Expensive To Install
Perhaps the biggest downside right now with geothermal energy is the upfront cost to get a unit installed and the in-ground portion set up for your home. According to the energy design website, Energyhomes.org, a typical home of 2500 square feet will cost between $20,000 to $25,000 to install.
You’ll also need a crew to dig and drill, because the two most common earth heat exchange systems, according to Keith, are loops of plastic piping buried deep in the yard or in vertical wells (with the plastic pipe installed in wells similar to a water well). “Buried loops are usually less costly than wells, but require much more real estate. The vertical wells are much less intrusive to the yard and can be installed on even the smallest of residential lots,” Keith says.
Because geothermal isn’t as popular as traditional HVAC, there are fewer professionals that do these types of installations. Consequently, there’s less competition for competitive pricing.
Difficult to Retrofit Existing Homes
If you’re building a new home, it can be pretty easy to install a geothermal system before the house and landscaping go in. However, if you’re hoping to install for an existing home, there will be some big excavations and drillings that could tear up your yard and may even destroy existing landscaping.
Repairs Can Be a Hassle
Although less likely to need as much maintenance as a traditional system, geothermal can be costly to repair if a tree root grows through your underground piping or a gopher digs and chews his way through it. The repair could involve significant re-excavating to find where the problem lies in the system. Finding a trustworthy professional to do a repair like that could be difficult, and the repair itself could be costly.
You’ll Still Need an Energy Source
In order to power the geothermal pump that brings the heat inside your house from the earth, you’ll still need another source of energy. The system needs minimal electricity, so you can use conventional electricity (from the grid), or if you really want to stick with environmentally friendly options, you can always install solar panels or a small wind turbine. Of course, that adds to the overall upfront cost, but it can pay for itself in the long run.
If you’re interested in looking further into geothermal energy, we recommend reading energy.gov’s article on choosing and installing geothermal heat pumps.
Lastly, if you like the idea of a very low energy bill but can’t quite afford a geothermal system, there is another alternative.
“A few years ago Carrier introduced their Infinity Greenspeed Heat Pump System. It’s a super high-efficiency heat pump that approaches geothermal operating costs but without the need to dig up your yard or bore wells,” Keith says. “It can be operated on off-peak power, giving you near-geothermal operating costs but at a much friendlier installation price.”