What Every Geothermal System Needs
- A geothermal heat pump, also called a ground source heat pump, to connect the earth to the HVAC system of the building.
- The earth, to be the heat source in the winter and the heat sink in the summer.
- Electricity, to help the heat transfer, whether it’s adding or removing heat from the building.
- Highly efficient and long life expectancy.
- HVAC equipment may be installed entirely indoors with no need for combustion
- Ability to be tied into the water heating system
- Consistent electrical load
- Limited maintenance requirements and few moving parts
- Green technology for the environment
How Does Geothermal Work?
It’s a buzzword becoming popular in HVAC applications, but how does geothermal work? Geothermal systems are a fascinating use of natural resources and free energy in heating and cooling systems. In a world of high energy costs and an increasing concern for the environmental impact of our dependence on fossil fuels, considering geothermal makes sense.
How Does Geothermal Work in the Direction Opposite Normal Heat Transfer?
Normally, heat escapes our buildings in the winter and enters them in the summer. This is why we have to add heating or air conditioning to keep our homes and offices at the optimal temperature. How does geothermal work to correct this?
Geothermal has tapped into the state of the ground about 20 feet below the surface of the earth. The inner earth at this depth is a constant 50-60 F year round even though the temperature of the surface above fluctuates throughout our seasons. So the earth can absorb heat when it’s summertime or plus 60 F at the surface. It can supply heat when it’s wintertime or less than 50 F at the surface.
How Geothermal Works with Three Critical Partners
The partners that work together in a geothermal heating and cooling application are the earth, a liquid that loops through the ground, and an indoor HVAC unit with a heat pump and associated ductwork. The earth is the heat source in the winter and the heat sink in the summer. The liquid that loops through the ground is usually water in a closed loop.
This loop can span vertically or horizontally depending on the right fit for the application. The water is the carrier of heat energy between the earth and the indoor unit. It’s circulated by a pump. The final piece, the indoor HVAC unit consists of a fan, compressor, and pump, and is powered with electricity.
The Benefits of Geothermal
Even the most environmentally-conscious among us can hesitate to invest in a geothermal HVAC system. It’s easy, after all, to get distracted by a higher installation cost and the disruption of your landscaping – but when you look at the benefits of a geothermal system, they easily outweigh these cons.
With mounting utility costs, free energy sounds too good to be true. But the earth is a free heat source and heat sink as long as we invest in the technology to harness it. Geothermal systems are indeed supplemented by some paid energy: electricity.
But the amount of electricity is far less than units using only electricity for heating and cooling. In fact, the earth’s heat helps geothermal systems use 25 – 50% less energy than conventional HVAC systems. Electricity is a supplement, not the main meal. Because of this lower energy usage, geothermal systems save you so much on your energy bills that most systems pay for themselves in 3-5 years.
Federal, state, and local governments were smart enough to see the benefits of geothermal from an environmental standpoint. Therefore, there are plenty of rebates and other incentives offered to geothermal consumers.
The Energy Improvement & Extension Act offers a 30% residential, 10% commercial one-time tax credit based on the total cost of installing a geothermal system. It’s valid through the end of 2016. Talk to your tax professional for information on the tax credit. Make sure your system meets Energy Star eligibility requirements and save receipts for this incentive.
Besides cheaper utility bills, you’ll have lower repair and maintenance bills. Geothermal units have few moving parts. The HVAC unit with its compressor, fan, and pump is entirely indoors and easily serviced. It’s not subject to the wear and tear of the elements. Periodic checks and filter changes can give your geothermal system at least a 20-year lifespan.
When you use fossil fuels like oil for your heating and cooling system, the combustion releases carbon monoxide, which is dangerous to humans and the ozone layer. Geothermal systems don’t rely on fossil fuels or combustion. Therefore, there is no risk of carbon monoxide leaks, flames, or odors inside the home. It’s also greener for the planet.