Geothermal for Consumers
Geothermal Home Energy
What is it and how does it work?
Geothermal home systems are not geysers or hot springs. Rather, they take advantage of the consistent year round temperature of the ground, which is approximately 45-75 degrees Fahrenheit. By pumping water through this temperate ground layer, very cold water in the winter or very warm water in the summer can be brought to a medium temperature that requires less energy to either heat or cool.
How does geothermal home energy work?
The geothermal system acts as both a furnace and an air conditioning unit. It relies on the temperate water circulated through pipes deep in the ground to heat and cool air. It feels just like regular A/C but uses less energy that is clean and renewable.
How much does a geothermal system cost?
The average geothermal system can cost roughly $25,000, — depending on a number of different factors such as home size and climate.There are state and federal incentives that can cover up to 60% of the total system cost, and you’ll see 20-50% savings on your heating and cooling costs every month. Depending on your local climate, you may be able to achieve payback on your system in as little as three years.
Other Useful Web Resources
Pacific Gas & Electric SGIP CaliforniaGeo Comment: You will note the absence of geothermal heat pumps in the SGIP program.
Source: Energy Upgrade California, Geothermal Home Energy
Geothermal or Ground Source Heat Pumps
Heat pumps move heat from one place to another – from outside to inside a home, for example. That’s why they’re called “heat pumps.”
Geothermal heat pumps are similar to ordinary heat pumps, but instead of using heat found in outside air, they rely on the stable, even heat of the earth to provide heating, air conditioning and, in most cases, hot water.
How Do They Compare?
Surveys taken by utilities have found that homeowners using geothermal heat pumps rate them highly when compared to conventional systems. Figures indicate that more than 95 percent of all geothermal heat pump owners would recommend a similar system to their friends and family.
Cost
You will have to add the cost of drilling to the total amount of the project. The final cost will depend on whether your system will drill vertically deep underground or will put the loops in a horizontal fashion a shorter distance below ground. The cost of drilling also will vary depending on the terrain and other local factors.
Durability
Geothermal heat pumps are durable and require little maintenance. They have fewer mechanical components than other systems, and most of those components are underground, sheltered from the weather. The underground piping used in the system is often guaranteed to last 25 to 50 years and is virtually worry-free. The components inside the house are small and easily accessible for maintenance. Warm and cool air are distributed through ductwork, just as in a regular forced-air system.
Since geothermal systems have no outside condensing units like air conditioners, they are quieter to operate.
Source: Consumer Energy Center, Geothermal Heat Pumps
Geothermal Heat Pump Basics
Geothermal heat pumps (GHPs), sometimes referred to as GeoExchange, earth-coupled, ground-source, or water-source heat pumps, have been in use since the late 1940s. They use the constant temperature of the earth as the exchange medium instead of the outside air temperature. This allows the system to reach fairly high efficiencies (300% to 600%) on the coldest winter nights, compared to 175% to 250% for air-source heat pumps on cool days.
Although many parts of the country experience seasonal temperature extremes — from scorching heat in the summer to sub-zero cold in the winter—a few feet below the earth’s surface the ground remains at a relatively constant temperature. Depending on latitude, ground temperatures range from 45°F (7°C) to 75°F (21°C). Like a cave, this ground temperature is warmer than the air above it during the winter and cooler than the air in the summer. The GHP takes advantage of this by exchanging heat with the earth through a ground heat exchanger.
As with any heat pump, geothermal and water-source heat pumps are able to heat, cool, and, if so equipped, supply the house with hot water. Some models of geothermal systems are available with two-speed compressors and variable fans for more comfort and energy savings. Relative to air-source heat pumps, they are quieter, last longer, need little maintenance, and do not depend on the temperature of the outside air.
Even though the installation price of a geothermal system can be several times that of an air-source system of the same heating and cooling capacity, the additional costs are returned to you in energy savings in 5 to 10 years. System life is estimated at 25 years for the inside components and 50+ years for the ground loop. There are approximately 50,000 geothermal heat pumps installed in the United States each year. Read more on Geothermal Heat Pump Basics
ENERGY STAR: Geothermal Heat Pumps for Consumers
Earning the ENERGY STAR means products meet strict energy efficiency guidelines set by the US Environmental Protection Agency. By choosing ENERGY STAR certified heating and cooling equipment and taking steps to optimize its performance, you can enhance the comfort of your home while saving energy. Saving energy helps you save money on utility bills and protect our climate by helping prevent harmful carbon pollution and reducing other greenhouse gases.
Geothermal heat pumps (GHPs) are among the most efficient and comfortable heating and cooling technologies currently available, because they use the earth?s natural heat to provide heating, cooling, and often, water heating.
ENERGY STAR qualified geothermal heat pumps:
- are over 45 percent more energy efficient than standard options.
- now include water-to-water GHPs
Water-to-water GHPs provide space conditioning and/or domestic water heating using indoor refrigerant-to-water heat exchangers.
Source: ENERGY STAR: Geothermal Heat Pumps for Consumers