Geothermal heat pumps

Photo of author
Written By Tony Lopes

Sustainable marketer and clean energy specialist. 

Geothermal heat pumps are a fantastic source of renewable energy for heating AND cooling your home.

This type of heat pump is also called a ground source heat pump and is a way for homes and businesses to cool and heat spaces and heat water.

There are costs associated with setting up a geothermal heat pump system so let’s dig in a little deeper (geddit?!) to understand how things work…

How does a geothermal heat pump work?

Most of the energy you will use this year will come from heating or cooling your home. In some areas this can be as much as 30% of your entire energy budget.

It makes perfect sense to ensure you are CONSERVING as much as energy as possible through proper insulation but have you looked at renewable energy sources for saving money on your heating and cooling bill?

This is where geothermal energy in the form of a heat pump might be an option – but how exactly does it work?

Ground Source Heat Pumps (GSHP) use the constant temperature of the earth below your home to heat or cool it:

  • Tubes full of fluid (antifreeze, groundwater or other liquids) are buried in a looped system deep underground near your house
  • A heat pump removes the heat from the fluid and uses that heat to warm up your house through a series of duct pipes
  • The thermodynamic laws ensure that heat will always flow from a hotter fluid to a cooler fluid, just like an ice cube absorbs heats and melts when you place it in water

What happens in Winter? It is warmer underground than above ground and so the heat from below will flow upwards to where it is cooler.

In Summer the opposite will happen. The air is warmer than underground and so heat will flow through the pipes to where it is cooler underground.

What does the heat pump itself do? The heat pump compresses the fluids in the pipe which increases the temperature even further and warms up the air in the house. The opposite happens in Summer to cool down the house.

The entire system is a very smart, closed-loop system and designed to conserve heat in the pipes and efficiently move hot or cold fluids above ground or below ground.

Technically though, you are not generating massive amounts of energy like you would from a geothermal spring. The geothermal heat pump system is useful because you are able to store and exchange heat using the underground system.

What are the different types of geothermal heat pump systems?

  • Open Loop Geothermal Systems: water flows from a source underground into the house and then back out of the house underground but not in a closed loop. The water that enters the system is constantly new and could carry particles, so a filter is required
  • Closed Loop Systems: water or refrigerant fluid remains in the system and never leaves or enters. This means there are no particles that need to be filtered and you don’t need to be concerned about potentially polluting the ground water since the fluid never touches the actual ground water

These systems can be set up in various ways (horizontal, vertical and more complex types of set ups) depending on how much space you have for your system.

Are geothermal heat pump systems expensive to install?

You have to dig down to install your heat exchanger piping and have a duct system in your house, so there is significant initial cost.

If you don’t have the space for a nice, big horizontal loop system, you will have to dig straight down to significant depths to set up a vertical loop system. Some large scale vertical systems require up to 30 boreholes of about 400 feet deep, so you can imagine that has some significant up-front cost. See an example at the Holy Cross Lutheran Church in Maple Lake, Minneapolis.

You will save money over time though – your heating bill will come down in Winter and in Summer you won’t need to spend as much on air conditioning.

People are using solar as their main source of power and using that to run the heat pump and warm/cool their house. This reduces your overall energy bill through the use of 100% renewable energy and efficient heat exchange!

You could expect an overall return on investment after about 8 years or so. When combined with solar, you can zero your energy bill over time.

Did you know? It makes sense to have a basement in your house because underground the temperature is more stable. This conserves energy in your home.

Geothermal heat pumps for hot water in your house

The excess heat from the geothermal heat pump can be transferred to a separate water heating system.

You can take hot showers and baths thanks to the heat that gets pumped up from underground, or the heat from the space in your house!

That’s truly a great use of energy. The same thing can be done for excess energy from any system, including hydro electric pumps where there is more energy produced than used.

Convert that energy to heat up water and you can have extra hot water at no extra cost!

What are the advantages of a geothermal heat pump system?

You are certainly going to be able save on your heating and cooling bills. You might even be able to get rid of some of those noisy and expensive fans, heaters and compressors.

Geothermal heat pump systems don’t rely on energy from fossil fuel to heat or cool your home. This is good for the planet because it slows down carbon emission which causes climate change.

You may even be eligible for tax credits, depending on where you live.

Check out the incentive programs and policies by state here.

Can I install my own heat pump system?

We always like to say you can do anything yourself if you are a qualified expert. So, what we’re saying is get an expert to do it right the first time and save yourself money in the long run.

Remember, you will have to do a lot of digging to install this, so be prepared for disruption and a mess in your yard. If you use a reputable, qualified installer the process should be as hassle-free as possible.

Over to you

What is your experience with geothermal heat pump systems?

We’d love to hear your views and comments – feel free to share them in the comments below.

Leave a Comment