A growing number of homeowners are finding savings in their own backyards by utilizing the earth’s natural energy to heat and cool their houses. It’s called geothermal energy – and it can save you some green while you’re going green.
The geothermal system – also known as ground source heat pump system (GSHPS) or geothermal heat pump (GHP) has been around for decades but is only now coming to the attention of many homeowners.
The Department of Energy and the Environmental Protection Agency have both endorsed GSHPS as among the most energy-efficient and environmentally friendly heating, cooling and water heating systems available.
How it works
The temperature of the earth – from a few feet to hundreds of feet down – is moderate and fairly constant. In many places it stays in the mid- to upper-50s all year. Instead of burning fossil fuels, a geothermal heat pump absorbs the energy stored in the earth to heat a home in the winter. In summer, a heat pump rejects the heat from the space and transfers it back into the earth – making it efficient and cost-effective.
To make it work, you need three elements: an underground loop system, a geothermal heat pump and an air-delivery system:
- Loop system: This is a system of high-density polyethylene plastic pipes buried in the ground. They’re filled with a mixture of water and antifreeze that circulates throughout the pipes. Open-loop systems circulate water drawn from a well.
- Geothermal heat pump: The geothermal heat pump extracts heat from the fluid within the loop. This heat is then sent into the house. In the summer, it extracts heat from the indoor air and transfers it to the fluid, which cools as it circulates through the loop.
- Air-delivery system: Most geothermal pumps use an electrically driven fan to distribute the air through ducts in the house.
According to the International Ground Source Heat Pump Association, a geothermal system is 50 to 70 percent more efficient than other heating systems, and 20 to 40 percent more efficient than available air conditioners. That means direct savings on utility bills.
How it saves you money
According to Bosch Thermotechnology North America:
- Geothermal heat pumps have the lowest life-cycle cost today – 25 to 50 percent less than a conventional system.
- You can save up to 70 percent on your energy bill, depending on your location and which GSHPS you use.
- Although the upfront costs are often higher than a conventional system, the cost can be recouped within a short period of time – as little as five to seven years.
- Take advantage of state, local, utility and federal incentives that promote renewable energy and energy efficiency. Look up rebates, tax credits and financing options in your area at the Database of State Incentives for Renewables and Efficiency, www.dsireusa.org.