Geothermal Heating and Cooling - Is It Right for you?

What is Geothermal Heating and Cooling?

Geothermal heating and cooling, also known as a ground-source heat pump, is similar to a standard air source heat pump. It does not create heat by burning a fossil fuel or using a strip heating. Instead, they collect heat from a source of either air or the ground by the use of compression and move it into the room (in the form of heat), or out of the room (in the form of air conditioning). This process is very similar to how a refrigerator makes for cold air inside, while warm air can be felt coming out of the bottom of the refrigerator near the floor.

Air source heat pumps are sometimes referred to as ductless HVAC units. It uses a compressor to collect the heat from the air and either bringing it into the home as heat, or to the outside as air conditioning. These types of units have significantly improved over the years but work harder in the extreme temperatures: single digit temperatures in the winter and 90+ degrees Fahrenheit in the summer.

Underneath the earth's surface remains a constant 55 degrees Fahrenheit all year round. By running a series of pipes through the ground with a liquid, a ground source heat pump successfully collect the heat to use in your home, and in the summer, send the heat back into the ground.  The pipes, or wells, require drilling down into the earth and typically are closed loop. Vertical wells are most common but residences with larger properties can utilize horizontal wells. 

Electricity is required to run the pump and compressor that distributes the conditioned air throughout your home. Average performance shows that that geothermal is about five times more efficient than electric strip heat, twice as efficient as high efficiency air conditions, and 50% more efficient than gas and oil furnaces.

More technical details of Ground Source heat pumps can be found at Dandelion Energy

Geothermal vs Traditional Fuel Burning Systems

While many sing the praises of a ground source heat pump, there's  number of factors to keep in mind. 

• Higher up front cost
  • The additional cost of drilling the wells are something to keep in mind. There are tax credits to alleviate - visit energystar.gov for more information
• Set it and forget it - temperature
  • Because heat pumps rely on moving heat between sources, geothermal systems cannot easily fluctuate temperatures rapidly, e.g. heat from 60 degrees to 75 degrees. This scenario would cause the electric strip heat will kick on, which can use up to 10 KW in an hour. The heat pump in normal mode is about 4-5x more efficient than electric strip heat, so the goal is to never run the strip heat, which will negate your savings. It's best to set it and forget it or change temperature slowly. That said, it's also best to avoid smart thermostats that adjust your temperature automatically.
• Registers (vents) will blow warm air (not hot air) in heating mode
  • Traditional furnaces that burn fuel will transmit heat in upwards of 120 degrees. 
  • Registers from a ground source heat pump will be noticeably cooler from 80-100 degrees. To some, this may feel chilly
• Larger amp draw during startup requires a beefier generator
  • Gas furnace homes can get away with running a smaller generator in the event of a power outage to run the furnace, while a ground source heat pump will require at least an 8,000 watt generator. 
• The system is very quiet
  • While I can hear the water pump running if I'm in the basement, there's no condenser fan running outside or unsightly oil tank that would need replacement in the future
• Long expected life
  • Heat pumps last about 20-30 years and the underground piping can last 50 years+ 

Is Geothermal For You?

There can be many factors impacting your decision to consider geothermal in your personal or investment project. Each have their own advantages and disadvantages:

Existing home

• Geothermal needs to utilize forced hot air ducting. Homes with hot water or oil baseboards would need to be converted to ducting which is likely going to be cost-prohibitive. 
• Ductwork should be insulated, otherwise heat loss will force the system to work harder (and likely kicking on the auxiliary heat strip, negating operating savings)
• Home should be well insulated already and have minimal air leaks to avoid engaging the auxiliary strip heat
• Yard access needed for drilling. Fences may need to be removed or taken down for allow for machinery to pass through.

Long Term/Short Term Rentals

• Ability to brand your rental as more eco-conscious
• Lower operating costs
• Reduced maintenance and longer life
• If an issue does occur, it might be more difficult to find emergency service that can assist

New Construction

• While upfront costs are higher, current federal tax credits help reduce the gap between a traditional furnace and central air setup.
• In more rural locations lacking natural gas availability, the advantages over traditional oil furnaces and electric heat are more pronounced
• Better access for drilling since landscaping and structures likely to not exist yet

Fix and Flips

• In a competitive market a home utilizing alternative energy can set your property apart as more buyers are looking to reduce their carbon footprint and reduce energy costs, especially as fossil fuels can increase in volatility. Budgets would need reprioritization as this can cut into the budget.