Architects like to hang around together. We like to talk about how the built environment can be made better to support our living conditions. That’s why we’re architects.
One night, we had an interesting conversation during happy hour after work.
J has a house. She is planning to install a geothermal system along with solar panels in an attempt to reduce her utility bills, reduce her reliance on oil and become more energy efficient.
I suggested it would be great to document the process. Make it a case study and share the learning experience. It would be great to understand the costs of such a project and calculate the return on investment. See how far the numbers go.
Geothermal is a fascinating type of energy.
It is energy that is generated and stored in the Earth. Imagine your house just sitting on the ground. Rooted into it. The ground transfers heat to your house during the winter. Heat from the ground can be delivered straight to the existing heat distribution system, whether it be forced-air, radiant-floor, or baseboard hot water.
Pipes are laid in the ground below the frost line. A fluid is pumped through these pipes. Heat is picked up by the fluid. Then the heat pump concentrates the heat to deliver it to the house in the winter. The process reverses in the summer.
A geothermal system is a fancy term for a ground-source heat pump (GSHP).
Installing this system is one of the better ways to improve and clean the environment. It replaces oil and coal to provide heating and cooling. Traditional furnaces and air conditioners are no longer needed in your home. Air pollution is reduced.
Geothermal energy is the most reliable of all the clean energy sources.
Geothermal works just the same given any temperature above ground. Solar and wind depend on the weather. As temperature changes from day to day and from season to season, they perform differently.
Temperatures 10 feet below the ground hold steady between 50 and 60 degrees F. This is where geothermal works its magic. Soil temperatures are warmer than air in the winter and cooler than air in the summer. Geothermal systems use the steady temperature to heat and cool houses.
Geothermal systems are installed independent of location. Solar and wind strategies are based on the natural topography. To be effective, they have to be in certain natural conditions. You can’t go solar if you’re in shade. You can’t use wind if you live in a valley.
Geothermal requires less land than solar and wind energies. Solar is restricted by the amount of photovoltaic (PV) panels you can place on the roof and on the ground. Wind is restricted by surrounding obstructions and the turbine is typically located a good distance from the house. For example, a geothermal power plant requires 10% of the land needed by a solar farm to produce the same amount of energy.
No outdoor equipment required. It’s compact and saves space.
Isn’t geothermal a great thing to install for your home?
However remarkable, a geothermal system is not what I would think of first to fit a house with a renewable energy source. Atleast not today. To install one in the Northeast costs around $40,000. Architects know very well how much impact the budget has on a project. It’s a killer.
The technology can be costly because a geothermal system requires extensive excavation. Holes have to be bored. Trenches have to be dug. A ground loop has to be made. And pipes have to be buried.
Tapping into the ground is not easy. You’ll pay more upfront to save a lot in heating and cooling bills.
The large upfront cost is based on the complexity of the geothermal system. It is essentially custom engineered and installed. Multiple suppliers come together instead of one. And each supplier is responsible for the whole system to perform properly.
With all these parts and suppliers, having a poor installation just makes matters worse. Especially when the parts are buried underground.
A GSHP system is not a packaged unit like its cousin, the air-source heat pump system (ASHP).
This is getting complicated. I know. But, you may already have an ASHP installed in your home. Air-source heat pumps are also commonly known as minisplits. Mitsubishi and Fujitsu make them.
They look to the sky and draw heat from the air. They can even draw heat on cold winter days. Cold outside air can be used to warm your home. This can be done when the outside air is warmer than the refrigerant in the ASHP. Heat is transferred to the refrigerant, then concentrated and delivered to heat your home.
In the summer, they operate in reverse, extracting heat from your home, and cooling it down.
ASHP systems operate the same way as GSHP systems do. One captures heat from the air. The other captures heat from the ground. But ASHP systems are often ductless. While GSHP systems require air ducts to move the heat. Adding to their complexity.
Of the two, ASHP systems blow GSHP systems out of the ground in sales. They are more commonly used in heating and cooling houses. The packaged systems are highly engineered. They are very reliable. If there is any trouble, you can go back to the one supplier.
Air-source heat pumps produce 3x more heat energy than the electrical energy they run on.
Comparatively, ground-source heat pumps produce 4x that. This means greater efficiency.
When you have low heating loads, this does not matter. The greater operating efficiency of the ground-source heat pump does very little to the large upfront cost. Yet, if you live in a really cold climate with huge heating loads, the GSHP system may be better than the solar PV.
According to the U.S. Department of Energy (DOE) and the Environmental Protection Agency (EPA), GSHPs are the most efficient, environmentally friendly and cost-effective space heating and cooling system on the market. These systems use small amounts of electricity to run their equipment. They run about 25-50% less than conventional heating and cooling systems.
They offer the lowest carbon dioxide emissions on that same note.
It’s time to consider the possibilities. Go to the Homeowner Guide to Geothermal Heat Pump Systems here and find out if it’s right for your home. There are more than a million geothermal systems out there already. And they are proving their worth.