-How Geothermal Works
-Why Go Geothermal?
The EPA (Environmental Protection Agency) and the DOE (Department of Energy) concluded that geothermal heat pumps are the most environmentally friendly and cost-efficient way to heat and cool your home. Geothermal systems emit no carbon dioxide, carbon monoxide, or other greenhouse gasses.
How Geothermal Works
Geothermal heat pumps are one of the most efficient ways to heat and cool your home. They can achieve efficiencies two to three times greater than commonly used air source heat pumps because they rely on the relatively consistent ground temperatures to transfer heat to or from a home. Across much of the United States, the temperature of the upper 10 feet of the ground remains between 45°F and 75°F, and often between just 50°F and 60°F. By contrast, air temperatures can range over the course of a year from below 0°F to over 100°F.
A horizontal closed-loop system is typically most cost-effective for residential installations. It requires trenches at least four feet deep. The most common layouts either use two pipes, one buried at six feet, and the other at four feet, or two pipes placed side-by-side at five feet in the ground in a two-foot wide trench. The Slinky™ method of looping pipe allows more pipe in a shorter trench, which cuts down on installation costs and makes horizontal installation possible in areas it would not be with conventional horizontal applications.
Source: U.S. Department of Energy
Why Go Geothermal?
1. Federal Tax Credit—30% of total cost
2. Annual Energy Savings – $400-$1,800/year.
3. Financing is offered by the District of Columbia
4. Most energy efficient system available
5. Cleanest way possible to heat
6. No noisy outdoor condenser
(1) Tax savings/credits estimates should be discussed with your individual tax advisor. Click here for tax credit information from EnergyStar: http://publicaccess.supportportal.com/link/portal/23002/23018/Article/19320/Is-there-a-tax-credit-for-geothermal-heat-pumps.
(2) Based on a 4-ton heat pump for a 2,000-square foot house.
(3) DC offers Property-Assessed Clean Energy financing. Click here for more info: http://www.dsireusa.org/incentives/incentive.cfm?Incentive_Code=DC12F&State=federal¤tpageid=1&ee=1&re=1.
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 5–10 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
1. Determine if you have enough space around your house for a geothermal system. A typical residential, vertical loop can be installed in an area as small as 10’ x 20.’ However, the area must be accessible to a drilling rig and free of utilities. Also, a 140’ trench is needed per ton for your geothermal unit, with 15’ of space between each trench. For example, a 4-ton system would require a space 140’ x 45’ free of utilities.
2. Figure out how much you currently spend on heating and cooling so you can determine how much your savings will be. You should expect your heating and cooling bill to drop 40%-80% by switching to a geothermal system.
3. Select an Installer*
Get three estimates for your geothermal system. You can talk to members and get their recommendations.
Key Considerations for Choosing an Installer:
- track record
- have they worked in DC before?
- how long have they been in business?
4. Once You Select an installer and sign a contract.
The installer will guide you through the process, and the permit process.
*CPEC does not endorse any products or services.
U.S. Department of Energy
Information about geothermal systems.