Yes, geothermal heating and cooling systems are more energy efficient than traditional air-source HVAC systems. Read on to learn how geothermal HVAC units can be nearly 400% more efficient and why geothermal heating and cooling is a cost-efficient option for your home.
Geothermal heating and cooling vs. traditional HVAC systems
The biggest reason to add a geothermal HVAC system to your new home or retrofit one for an existing house is that geothermal HVAC units are very efficient. Check out a few quick facts on geothermal heat pump system efficiency:
- According to Energy.gov, geothermal HVAC systems can be 300-600% more efficient than traditional HVAC systems on cold winter nights.
- Energy.gov estimates that geothermal HVAC systems are typically 25-50% more efficient than traditional air-source systems.
- According to Energy Environmental Corporation, for every unit of energy a geothermal heat pump system uses, 3-4.5 units of energy are supplied as heat. That means a geothermal heat pump is multiplying the energy it uses, making it 300-400% efficient, while fossil fuel furnaces may not even return 100% of the energy units they use to operate.
So, is a geothermal HVAC system worth it?
A geothermal HVAC system can definitely be worth it. Because they’re so energy efficient, you don’t have to use as much electricity to get the same heating and cooling results for your home as you would with a traditional HVAC system.
On top of being more energy efficient, which saves on utility costs, these systems also last longer, in large part because a system’s fan, compressor and pump tend to be housed indoors. A geothermal heating and cooling system also needs less maintenance, leading to lower system expenses over the lifetime of the system.
Is the initial cost making you think twice?
Despite how energy efficient a geothermal HVAC system is and the long-term savings that a new geothermal heating and cooling unit can bring, the initial cost is often a barrier to purchase for residential homeowners.
If this is a factor for you, take the time to browse geothermal heating and cooling options for residential homes. Taking advantage of tax credits and rebates may help you get the geothermal price a little closer to traditional HVAC system costs and according to Energy.gov, you’ll likely see the higher costs of purchase and installation returned to you after 5 to 10 years.
Plus, there are federal renewable energy tax incentives that can help lower the cost of a new geothermal heating and cooling system. Federal tax incentives last until 2022, but yearly tax incentives also lower after 2019, so start considering your options now.
What makes a geothermal HVAC unit so efficient?
Two things make a geothermal HVAC unit more efficient than a traditional HVAC system.
1. Resources used to run the system
Geothermal HVAC systems use a small amount of electricity to power a geothermal heat pump to transfer heat.
This is more efficient than traditional HVAC systems because a traditional HVAC system uses electric or natural gas power to heat or cool air to the temperature you want inside. Also, a geothermal HVAC system isn’t burning large amounts of gas or electricity to warm up air. Geothermal HVAC systems instead take existing heat in and out of your home to maintain desired temperatures. You can read more below about how residential geothermal energy works.
2. Temperature Consistency
Outdoor temperatures tend to fluctuate a lot, which can mean a traditional HVAC system works hard to raise or lower temperatures during colder or hotter seasons.
However, geothermal HVAC systems are changing temperatures inside your home based on ground temperatures, which vary less than outdoor air temperatures. And when they transfer heat, a constant ground temperature combined with system protocols that prevent overcooling or overheating the ground mean that the system can work on and on and on and on…
Also, don’t get geothermal heat pumps confused with air-source heat pumps. An air-source heat pump isn’t recommended for homeowners who live in areas of the country with temperatures regularly dropping below 40 degrees.
However, because of ground temperature consistency, and the difference between the underground temperature and above ground air temperatures, a geothermal heat unit still works in cold areas. After all, according to a report from the Swedish Center of Geoenergy, around 20% of Swedish households, or 1 in 5 Swedish households, have a ground-source heat pump.
To ensure that your system can operate well in cold extremes, verify with your HVAC professional that you have a properly sized loop field for when cold weather hits. A properly sized loop field will prevent your electric heating system from running overtime and prevent drawing so much heat from the surrounding soil that it freezes. You’ll also want to make sure you don’t try to heat your home too quickly.
If all those recommendations made no sense to you, read on to learn how a geothermal HVAC system actually works to heat and cool your home,
How residential geothermal energy works in a home
A residential geothermal heating and cooling system uses the constant temperature of the upper 10 feet of earth to maximize heat transfer to and from a home. Because shallow ground temperatures hover between 50 and 60 degrees Fahrenheit all year long, a residential geothermal HVAC system always has a natural resource to draw additional heat in the winter or to deposit excess heat in the summer.
How it works in the winter
In the winter, a heat pump uses a small amount of electrical power to move heat from the ground to your home to warm it up. Remember when we talked about units of energy being converted into heat? That’s where this comes in. While geothermal HVAC systems do use some electrical power, they can convert one unit of electric energy into 3-4.5 units of heat transfer energy.
How it works in the summer
Laws of physics mean you can only transfer heat, so in the summer, a geothermal heat pump uses electricity to move excessive heat from your home to the ground, which can absorb it, since it’s cooler than above-ground temperatures in the summer.
How do these heat pumps work? They work alongside in-ground heat exchanger systems, which are systems of pipes buried in the ground. The pipes could either water or refrigerant fluid running through pipes in the house to collect and transfer heat.
Pairing a geothermal system with other summertime energy-saving measures can ensure that your electric bill will be lower than your non-geo neighbors.
It can heat your water, too
A cool perk about the geothermal heat pump system is that if you use a geothermal heating system and add a device to your system that heats your household water, you can get free hot water during the summer. The device removes heat from your home and uses the heat to warm your household water! In the winter, your geothermal heating system will use heat from the ground to heat water at about half the cost of a typical water heating system.
Is a geothermal HVAC system the right fit for your home?
Some of the following factors will determine whether or not a geothermal HVAC system is the right fit for you, especially if you’re retrofitting your home.
- Consider your ideal indoor temperature
According to the U.S. Department of Energy, the ideal indoor temperature for a geothermal heat pump retrofit project (adding a geothermal heating system to your home post-construction) is the most important factor for deciding if a geothermal HVAC heat pump is right for you. To start evaluating it as an option, consider that a geothermal heating and cooling system is a good fit for indoor temperatures maintained at 68-78 F for at least 40 hours a week.
- See if you can use existing air ducts
Installing a new HVAC system in your home will cost less if you can incorporate existing systems in your home. Ask your local HVAC professional to evaluate whether or not your existing system is compatible with a geothermal heating and cooling system.
Energy.gov says additional factors also play into deciding on whether or not a geothermal HVAC heat pump is right for you and which type of system to choose for your home:
- Your local energy costs. Depending on where you live, local electric costs may be incredibly high and it could be more economical for you to heat your home with natural gas.
- The timing of installation. The best times to consider buying a new geothermal HVAC system tend to be if you’re already planning a major renovation project or if you’re building a new home.
- The type of soil that makes up your property. Your property’s terrain determines how well heat transfers and how much geothermal loop piping you’ll need to install.
- The size of your property. Horizontal loop systems are more cost efficient to install, but require more property space than vertical loop systems, which have higher installation costs.
- Your surrounding landscape. No matter what type of geothermal system you install, it’s going to take some digging, so depending on your local HOA, you may or may not face some construction challenges. Also, if you have surface water nearby such as a stream, pond or lake, you may be able to use the water to condition the heat exchanger.
Geothermal heating and cooling systems clearly have many advantages and could be the perfect way to save money on energy costs over time. If you’re looking for other ways to save money at home, check out more ways to go green at home.
Want to find out if a geothermal HVAC system will work for your home? Schedule an appointment with your local Trane dealer to learn about your options.