From Guest Blogger Patrick Gibson: Geothermal Heating For Sustainable Homes
The costs of energy are on the rise around the world. But the good news is that today there are sustainable heating and cooling options available for home-owners looking to build or remodel a green home.
Geothermal heat pumps are a very popular option that can heat the home in winter, and can work as an air conditioner in winter. This is possible because of the way the system works. Simply reversing the heating process can make the heat pump work as a cooling system.
How A Geothermal Heat Pump Works
The heat pump uses a simple process of exchanging heat with the earth. The device that makes this possible is called a ground heat exchanger. Many people will be familiar with the air-source heat pump. This type of heat pump exchanges cold and warmth with the air outside. In contrast, the geothermal heat pump takes advantage of the constant temperatures underground, a few meters below the surface of the earth and the frost line.
Ground temperature below the earth’s surface remains a constant 7 to 24 degrees, depending on the area. This means that in summer, the temperature is cooler than the air over the ground and in winter, it is warmer.
Every geothermal heat pump has a system of pipes buried near the ground, containing either water or an antifreeze-water mixture. This fluid conducts heat to the ground in warm weather, and in cool weather, it transfers the heat to the soil around the home.
A pump then removes the heat from the fluid and transfers it to the building in winter, and the reverse happens in summer. A system of ducts is used to send the heated (or cooled) air throughout the house.
The Benefits of Geothermal Heating
The temperatures below the frost line is usually so steady that heat pumps can work with double the efficiency of air-source heat pumps. This is especially true in extremely cold winters.
While initial installation costs can be high, home-owners gain back these costs in 5 to 10 years. This type of heat pump also has a longer life than most others. The underground components can last as long as 50 years – while indoor components can last up to 25 years. Many manufacturers and local utility providers also offer rebates on such eco-friendly systems, which can help to reduce costs. Tax rebates may also be available from the government as incentives.
Things To Consider When Installing A Geothermal Heat Pump
It should be noted that a geothermal pump cannot work on its own in an otherwise inefficient home. For maximum efficiency, it should be installed in a home that is generally energy efficient. In other words, climate-appropriate insulation and energy efficient doors and windows used in conjunction with the pump will generate the best results. Old homes should be upgraded with these features before installation. The long-term energy savings will usually offset any initial costs that may be involved.
Whether or not a geothermal heat pump is suitable for your home can only be determined by engineering and mechanical details. A contractor can help you determine whether this is the right energy solution for your home. If not, they may be able to offer other alternative cost-effective and energy-efficient solutions.
Photo: gleasongeothermal.com
Patrick Gibson’s article on geothermal systems for residential homes touches the basics of how they work but does not mention and include Direct Exchange (DX) geothermal technology which is considered more efficient, less complicated and uses copper earthloops in lieu of the HDPE plastic type ground loops used with water source type geothermal technology and circulates environmentally friendly refrigerant instead of a water/glycol solution. DX type systems are a viable consideration as they can cost less initially, the fields require much less space and they require less maintenance. Both types of geothermal technologies are far and above any air to air type, brand or model of heat pump system for longevity, efficiency and performance. Both types of geothermal can also provide you with domestic hot water needs very efficiently with far less cost than any other type of water heating device. With current tax credits and other incentives the initial cost is reduced to approximately the cost of a high end air to air type heat pump system which gives you far, far less for your investment with a much higher repair rate.
You make an excellent point that he house should have such upgrades as better insulation before putting in geothermal. There are so many inexpensive things any homeowner can do to improve the energy efficiency of their home. In my opinin the new standard for new construction should be geothermal. That would go a long way to lowering the need to burn fossil fuels.
Great point. That and many other concepts in sustainable building will soon become the norm, I believe.