Proper Geothermal System Sizing

First and foremost, we’d like to wish all of our viewers a very happy New Year! We’re excited about 2012 and the potential the geothermal heating and cooling industry has to grow in the coming year. We’d like to start this year off (blog wise, at least) by touching on something that we think is of the utmost importance to our industry’s growth and success. Perhaps the most important part of a geothermal installation takes place before the ground is broken. That’s right – sizing the geothermal heat pump system correctly can be the make or break factor when it comes to both comfort and savings.

sizing geothermal system

How so? Well, let us explain. The size of your heat pump system is dependent a few variables, including the size of your home, the amount/integrity of existing insulation, and the climate in your area. To read more about this, check out our page on pricing a geothermal system. Considering these variables, it’s actually pretty intuitive that incorrect system sizing can be detrimental to both comfort and savings. Let’s look at cases of undersizing and oversizing (and possible respective consequences).


When a system is oversized, the heat pump is too large for the house size, insulation, and climate. Basically, you’re getting more than you need (and paying more, too). The initial cost of installing a geothermal system is often cumbersome as it is. As the cost of the actual heat pump is a good portion of this cost, you’ll want to avoid paying for more than you actually need. Obviously, the lower the initial cost of the system and its installation, the lower the payback period.


When a system is undersized, the heat pump is too small for the house size, insulation, and climate. In essence, you’re getting a system that isn’t sufficient for heating and cooling your home. While you may pay less for a smaller heat pump (which often adds false appeal to undersizing), there’s a possibility (depending on your individual circumstance) that the system won’t be optimal for home comfort or operating cost. It’s important that we don’t sacrifice years of comfort for the appeal of a lower initial cost.

We hope that you, having seen both sides of the incorrect system sizing coin, realize the importance of doing your due diligence, getting second and third opinions, etc. in searching for a geothermal heat pump system installer. You don’t always need the biggest, baddest heat pump, and likewise, you don’t always want to take the lowest bid. The goal, as always, is to get the system that’s right for your home at the right price. A good place to start is to talk to a geothermal expert in your area. Again, though, the more information you gather, the better. Triangulate. Triangulate. Triangulate.

If you have any questions, feel free to contact us!

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