What is a geothermal system?
A geothermal system essentially consists of a means of transferring the earth’s stored heat energy by some mechanical conductor and then slightly manipulating the temperature either warmer or cooler by a heat pump. Stored energy is moved by a closed loop pipe buried in the earth, carrying an antifreeze liquid that absorbs the earth’s temperature. Distribution and transfer of this temperature occurs through radiant piping or through an air exchanger / blower system within the home. Geothermal energy can also be successfully recovered from ponds, streams and lakes under certain conditions.
Does geothermal work in different climates?
Yes. Geothermal works in all different climates. With very few exceptions, the earth’s temperature universally is approximately 52 – 55 degrees at a below surface depth of 8’. This ideal temperature range allows geothermal systems to heat and cool buildings at ideal indoor comfort ranging between 68 and 73 degrees.
What things must be considered when installing a geothermal system?
First, a properly installed geothermal system begins with careful engineering. The heating and cooling loads of the home or building must be identified, performance criteria established and distribution methods (forced air/ radiant or combination) determined. The building envelope’s tightness and insulation R values must also be analyzed and factored in along with soil conditions for the ground loop construction.
Do geothermal systems work with other renewable energy equipment?
Yes, in fact Solar PV, Solar Thermal and wind energy systems are often used with geothermal to create a “Net Zero energy” or “off the grid” home. Wind turbines and / or solar PV systems are generally used to address the electrical power demand of the home.
Are these systems expensive?
The initial cost to construct a geothermal system is generally, more expensive than a comparable high efficiency fossil fuel HVAC system. However much of the higher costs are offset through generous federal tax rebates. Also, many local utility companies offer additional incentives and purchase rebates for geothermal installation. Generally, in the final analysis, the net cost premium of installing a geothermal ground source heat pump system is almost negligible compared to that of a high efficiency HVAC fossil fuel system. Geoexchange /Geothermal typically has the lowest life-cycle cost of any heating and cooling system. Moreover, installation costs have declined substantially in recent years, and they’re expected to continue to fall, as more builders and contractors offer geoexchange systems, and as the industry develops innovative ways to install the systems faster and more efficiently. Altogether geoexchange systems are a sound investment. The amount they save the homeowner every month in energy costs is more than enough to offset their higher installation cost.
What are some of the advantages of geothermal?
The advantages are compelling. Here are just a few:
1) Comfort – ask any homeowner with a geo system and one of the first things they mention is how comfortable their home is. There are a couple of reasons for this – First, there is no combustion with a heat pump, i.e. you are not burning fuel. Therefore, since you are not ‘cooking’ the air which removes moisture, a geo home retains higher humidity levels leading to greater comfort (especially in winter). Secondly, geo systems tend to provide more even heat by using a steadier, but lower volume of air distribution. You won’t miss those hot blasts of air that go on and off with conventional furnaces.
2) Safety – with no combustion, there is no danger of CO2 poisoning or explosions due to fossil fuel leaks.
3) Maintenance – there is very little maintenance with a geo system
4) Noise – geo systems are generally very quiet. Ever notice how noisy air conditioners are in the summertime? Not so with a geo system, as it is uses the same equipment for air conditioning as for heating – it’s the same unit. Think of your refrigerator – which is a heat pump – it’s not a very noisy machine.
5) Monthly bills – you will pay less to heat and cool your home from day one. Geothermal systems use electricity to move fluids and heat (but not to create the heat) so your electric bill may be higher (unless you use electric resistance). But you will no longer need gas/oil for heating and your air conditioning is much more efficient -overall you will use less energy and your total utility bill will be lower.