Thinking About Adding Central AC? Read About Geothermal First.

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Ah, central air conditioning. It’s a wonder of the modern age that can transform any sweltering summer day into a cool, comfortable one.

If you’re thinking about installing central AC in your home, there are a few things you should know.

In this post, we’ll look at the major conveniences of central air conditioning, take a look at the process involved in installing it, and talk about why a geothermal air conditioning system might just be the answer for you.

Central air conditioning gives you the comfort of temperature control more efficiently than a window unit. A window unit can cool a single room fairly well, but if you need a few throughout the house, the energy costs can stack up fast.

Central air also provides you with improved air quality in every room. Thanks to the filter in your air conditioning system, you can stay cool and breathe cleaner air.

How much does it cost to install central heating and air conditioning?

The first step in installing a central air conditioner is for the contractor to perform a site survey. How old the house is, whether there is existing ductwork, and how big the air conditioner must be are all considered.

Installing new windows, updating insulation, and caulking and sealing any cracks can help keep the cool air in. This diminishes how hard the air conditioner has to work as well. You could do these things before or after the site survey. The site survey itself and any additional improvements can contribute to the overall cost.

Installing central air in a house with existing ductwork

If your home already has a functioning air duct system, adding central air can be fairly easy and less costly. The technicians will inspect the existing ductwork to make sure it’s sound and sealed well enough to move the air through your home efficiently.

Then, they install a split system. This consists of evaporator coils cased inside a unit usually in your attic or utility room, and a big metal box containing a condenser outside.

Essentially, the evaporator coils use refrigerant to remove warm air and humidity from inside the house and send it through the ductwork to the condenser outside. The condenser then releases this warm air outside. The remaining cool air is distributed throughout.

With geothermal air conditioning, the process is similar, except that there’s no need for an outdoor condenser. A geothermal heat pump collects the warm humid air through the ductwork and sends it to underground pipes to release the heat there.

Installing central air in a house without ducts

If your home doesn’t have existing ductwork, you’re not out of options. You could have air ducts installed for a traditional split system, or go with a ductless central air conditioning system.

A ductless system requires a compressor and condenser outside as well as several blower units inside. The process of absorbing the warm air happens on a room-by-room basis with the warm air collected and run through refrigerant tubing all the way to the outdoor condenser.

Generally, these systems are pricier than window units, and not as efficient as central AC. Installing either ductwork or ductless AC into your home would be a fairly big project to take on yourself, but straightforward for an HVAC technician.

Properly sizing a central AC system

Apart from having an efficiency-optimized air duct system and house in general, one of the most crucial elements in getting central air conditioning is properly sizing the system. It’s also obviously one of the biggest cost factors. This is definitely something you want to leave to the professionals.

Technicians will perform what is known as a Manual J calculation. This is a standard calculation set by the Air Conditioning Contractors of America. It takes into account the size of each room, how much energy is required to cool the air, and other factors, so be sure that you buy an AC unit that will work as it should.

Undersizing the air conditioning unit can lead to a home that never seems to quite reach the cool temperatures you’re looking for and a system that runs almost constantly. Oversizing can mean your air conditioner is a waste of money, space, and energy as well.

You’ll want a system that meets the Goldilocks rule of being just the right size to get the best return on your investment. Geothermal AC does this easily by performing similar load calculations and remaining the most energy-efficient option, no matter how hot it gets outside.

Installation and labor for central AC

The biggest factors in determining how long it will take to install central AC and how much it will cost are:

  1. The type and location of the AC unit
  2. Whether you need a ductwork update, total replacement, or new duct system installed
  3. The size of the unit

With these in mind, installing a new central AC system can take anywhere from a few days to two or more weeks.

All things considered, the total cost of installing central AC can range anywhere from $3,500 to $7,000 or more. Then you have a whole different set of expenses when it comes to heating.

How does geothermal compare to central AC?

If you opt for a geothermal system, you get both a heating and cooling system for the price of one. Once you have a geothermal system installed, you can use it to either heat or cool your home with the simple nudge of the thermostat.


Both central AC and geothermal cooling can give you the comfort of temperature control throughout the home more efficiently than a window unit or a portal AC can. These can cool a single room fairly well, but if you install a few throughout the house, the energy costs will stack up fast, and you’ll end up with hot and cold spots.

We can objectively measure and compare the efficiency of central AC and geothermal cooling through their Energy Efficiency Ratio, or EER. This value is calculated by dividing the energy output (AC) by the energy input (electricity). The greater the EER, the more efficient your system is, because less electricity is needed to produce the same result.

Geothermal systems are highly efficient, typically having EERs of 15 and above. Dandelion’s geothermal system has an EER of 16.7. Meanwhile, a central AC system with an EER of at least 11.6 is already considered to be very good.

Central AC systems have a reputation for being noisy, but it’s no secret why they’re as loud as they are. They’re fighting a perpetual uphill battle against science by forcing indoor heat to be absorbed into the hot outdoors, and consuming massive amounts of electricity in the process.

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


All of the air conditioning options that we’ve discussed require some form of energy input. Whether you have an army of window units and portable ACs, a central AC system, or a geothermal system, you can’t create cool air from nothing, so some amount of energy will be consumed.

Luckily, all cooling options run on electricity, not fossil fuels. So, the most sustainable AC option aside from handheld paper fans is the one that’s most efficient. In turn, the most efficient system uses the least amount of electricity, and that’s geothermal.


The upfront cost of geothermal is undeniably more than that of central AC. Dandelion’s heat pump is on the more affordable end of the geothermal spectrum, but it still comes out to anywhere between $1500 to $2500 per ton, not including ductwork. In contrast, central AC typically comes out to anywhere between $750 to $1300 per ton, not including ductwork.

However, beyond the price tag, there are some other important factors to consider. Geothermal is a two-in-one cooling and heating system, so after this one-time cost, you’ll no longer need to pay for a boiler, a furnace, fuel oil, natural gas, or propane for the winter. In the summer, you’ll also end up spending less on electricity than you did with central AC, window units, or portable ACs. Even though geothermal’s upfront costs are higher, operational costs are lower.

Installation Complexity

Both geothermal and central AC installation depend upon an existing air duct system that routes air distribution throughout the house. If you don’t already have ductwork installed, it’s important to do so before you install geothermal or central AC. Without ductwork, there’s no way for your AC system to pull warm air from your home and return cool air to it!

If your home already has functioning ductwork, adding central AC is fairly straightforward. Installers will first inspect the existing ductwork to make sure it’s able to move air efficiently into and out of your home, and then conduct a manual J calculation to estimate your anticipated heating and cooling needs. After that, you’re good to go for installing the three components of a central AC system: the evaporator, the condenser, and the compressor.

To avoid any mishaps, geothermal installation requires more time and more customizations than central AC installation does. At Dandelion, the process involves the same ductwork inspections and manual J calculations on top of other design considerations as well. The geothermal system includes a heat pump and ground loops, so there’s an indoor installation step as well as an outdoor drilling step. The full timeline can take weeks or months from the initial interest survey to the finished installation, so definitely make sure to plan ahead!

Equipment Lifespan 

Central AC systems typically last between 12 to 15 years, or 15-20 years if you’re willing to spend a little extra money on an “energy saver” system. 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, central AC condensers are left above-ground and outdoors, so exposure to the elements causes increased wear and tear. As a result, frequent system maintenance is encouraged, if not required.

Available Incentives 

As a renewable source for heating and cooling, geothermal systems are promoted at the federal, state, and local levels through financial incentives. Central AC systems also run on electricity, not fossil fuels, but they still consume more electricity than geothermal systems do, so there are no external incentives available for installing central AC.

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