Geothermal Cooling: Everything You Need To Know

Did you know that you can use your yard to cool your home in the summer? 

In this post, we’ll give you a thorough rundown of all things geothermal AC: what is it, how does it work, how does it compare to conventional AC systems, and how it differs from geothermal heating. We’ll also help you understand some of the major advantages of geothermal AC, including efficiency, cost, convenience, comfort, and sustainability.

I thought geothermal was for heating your home. Can geothermal be used for cooling? 

Yes! Your geothermal heat pump is actually a two-in-one HVAC system used for both heating and cooling. Despite the misleading name, geothermal “heat pumps” are just as effective at cooling your home in the summer as they are at heating it in the winter! 

How does geothermal cooling work?

Just to recap, geothermal heating works by moving temperature-conducting fluid through an underground loop of pipes beneath or near your home. This allows the fluid to collect the thermal energy deposited in the earth from the sun. This works well even in the coldest winters because the earth below the frostline is a steady 55 degrees Fahrenheit all year long. The heat is circulated back into the pump and then distributed evenly throughout your home using your duct work. 

Now, for the big question: how does the same geothermal heat pump that heats your home in the winter also produce AC for the summer?

Essentially, the heat transfer process works in reverse. Here’s the short explanation: As air is circulated through your house, your heat pump removes heat from the air and transfers it to the fluid that circulates to the ground. As the ground is at a lower temperature (55F), heat dissipates from the fluid to the ground. The experience of cold air blowing into your home is the result of the process of removing heat from the circulated air, transferring that heat to the ground, and returning cool air back to your home.   

Here’s a slightly longer explanation: The cycle begins when the compressor inside your heat pump increases the pressure and temperature of the refrigerant. This hot refrigerant moves through the condenser, where it comes into contact with and transfers heat to the ground loop fluid. This fluid is then circulated through your ground loop piping where it releases heat to the ground. 

But back to the heat pump. After transferring heat to the ground loops, the refrigerant moves through the expansion valve, which decreases both the temperature and pressure of the refrigerant. The now cold refrigerant then travels through the evaporator coil to come into contact with the hot air inside your home. The heat from the air inside is absorbed by the cold refrigerant leaving only cold air. This cycle repeats until your home reaches your desired temperature.

How does geothermal cooling compare to conventional air conditioning?

Efficiency 

When it comes to efficiency, geothermal AC beats conventional central AC by far. Your geothermal heat pump isn’t wasting electricity trying to pump indoor hot air into the already-hot outdoors; instead, it’s easily releasing heat into the cool underground. 

As you can imagine, your geothermal heat pump will always be effective and efficient at cooling your home, even in the hottest summers. Installing a geothermal air conditioner can reduce your electricity use by 25 to 50 percent! Taking advantage of geothermal cooling is a great way to avoid those painful spikes in your utilities bills over the upcoming hot summer months.

The greater the Energy Efficiency Ratio (EER), the more energy output you’re getting from your HVAC system compared to how much energy input it requires to run. An HVAC system with a EER of 3.4 is at the break-even point, where it produces as much energy as it requires. Geothermal AC systems typically have EERs between 15 and 25, while even the most efficient conventional AC systems only have EERs between 9 and 15! 

You may have heard of a few other efficiency measurement methods out there, such as Seasonal EER (SEER) and Coefficient of Performance (COP). However, all these different acronyms are just a confusing result of industry non standardization. Essentially, they all serve the same function. So, no matter what measurement method you use, the efficiency rankings of HVAC systems are still the same, and geothermal wins out every time.  

The more efficient your HVAC system is, the more bang you’ll get for your buck! Choosing an efficient HVAC system with a high EER like geothermal AC will help you minimize your monthly cooling bills. 

Cost 

It’s important to note the difference between upfront and operational costs: upfront cost translates to a one-time cost (or multiple one-time costs, if you choose to pay in installments), while operational cost recurs monthly. Conventional HVAC systems tend to have a lower upfront cost but higher operational costs, while the reverse is true of geothermal HVAC systems. 

In the end, geothermal AC usually works out to be much more affordable than conventional AC, because after the higher upfront cost, there are very low operational costs. The operational savings of geothermal AC become immediately clear when you see your electric bill: geothermal heat pumps lower your electric usage in the summer! 

The best part is, after several years, your geothermal system ends up paying for itself in savings! We call this time the “payback period”.  

Other relevant cost considerations are the federal, state, and utility incentives offered to homeowners who upgrade to geothermal HVAC from conventional systems. Geothermal does not burn fossil fuels to heat and cool buildings, so renewable energy programs often use financial incentives to further encourage homeowners to upgrade and go green. These financial incentives further reduce geothermal’s upfront cost while operational cost remains the same. This means that your geothermal “payback period” shortens even more with financial incentives — in some cases, it becomes as short as five years! 

Convenience 

Geothermal is pure convenience compared to conventional HVAC. If you could simplify and reduce the number of bits and pieces required to achieve the same results, why wouldn’t you? In conventional HVAC, different appliances serve different functions. These various moving parts play their part depending on the season.

Perhaps you heat your home using a central furnace powered by natural gas, electricity, or even oil. Or maybe you have a boiler, which runs on natural gas, fuel, or oil. Maybe you use gas-fired or electric space heaters in addition to a wood-burning stove or fireplace.

Then, in the summer, none of this equipment is used and your attention turns to the central air conditioner with its various parts, both inside and outside. At a minimum, conventional heating and cooling require two distinctly different systems for different seasons.

A geothermal system is made up of only two parts: ground loops and a heat pump. This simple, straightforward, and convenient system can provide both heating and cooling, which saves you money, space, and so many headaches. Instead of installing, operating, and maintaining at least two separate pieces of HVAC equipment in your home, you could just have one that serves your home year-round. 

Maintenance and Lifespan

Conventional central air conditioning systems typically last between 12 to 15 years. Often, the main components significantly degenerate within the first 5 to 10 years, causing a steady decline in efficiency. They also require more regular maintenance and are more likely to incur damage as the compressor is exposed to the elements.

A geothermal cooling system pump lasts well over 20 years, and the underground looping system lasts well over 50 years. They also require very little maintenance, if any, during that time. With no exposure to the elements, the parts that keep a geothermal system running last longer and maintain excellent efficiency during this time.

One reason for a geothermal system’s extended lifetime is its protection from the elements: the ground loops are buried deep underground and the heat pump is sheltered indoors. Both parts of the geothermal system are far less likely to suffer seasonal damages due to fluctuating temperatures and abrasive weather patterns such as snow and hail. 

In contrast, conventional AC units are left above-ground and outdoors, so exposure to the elements causes increased wear and tear. As a result, regular system maintenance is encouraged, if not required. 

Comfort 

Conventional AC units have a reputation for being noisy, but it’s no secret why they’re as loud as they are. Conventional AC units are fighting a perpetual uphill battle against science by pumping indoor heat into the hot outdoors, and consuming massive amounts of energy in the process. 

Geothermal AC systems are much quieter because they direct hot indoor air into the cool ground. Instead of worrying about overworking your AC, you can relax and enjoy the refreshing comfort of a quiet, cool home in the summer. 

What are the environmental and health impacts of geothermal AC?

There are no negative health impacts of geothermal cooling, and no net negative environmental impacts either! 

Geothermal HVAC systems use only the earth’s temperature and electricity to generate heat or AC for your home. In some cases, geothermal HVAC may still not be fully renewable because some utilities providers only supply electricity sourced from nonrenewable energy. 

However, you can rest assured that geothermal’s indirect use of nonrenewable energy is still less than any conventional HVAC systems’ direct use of fossil fuels in large quantities. So, in the big picture, using geothermal instead of conventional AC reduces your environmental footprint. 

Geothermal is also better than conventional HVAC when it comes to impacts on human health. When you turn on the heat in the winter, conventional combustion-based heating systems create carbon monoxide as a byproduct, which is poisonous and causes sickness or even death. Carbon monoxide is odorless, tasteless, and colorless, so it’s often undetectable until it’s too late. 

Meanwhile, geothermal HVAC systems don’t burn fossil fuels at all, whether in the winter or in the summer. With geothermal, there are no health hazards to you or your loved ones! 

Even better, the air quality inside your home remains pure, as there are no fumes or particulate matter created by burning fossil fuels. 

On a broad scale, this applies not only to the air quality of your home, but also to our atmosphere in general. Upgrading to geothermal HVAC is one of the most impactful things you can do to support a healthier environment. Air conditioners in the U.S. alone release over 100 million tons of carbon dioxide into the atmosphere each year. 

Is geothermal right for you?

Geothermal is a healthy, safe, and sustainable alternative to conventional AC systems, which have negative consequences on both the environment and on human health.  

Thinking about upgrading to geothermal AC for the summer? Now’s the time to reach out and get more information about geothermal cooling for your home. Get in touch with us here!