Tuning and Replacing your Central Air Conditioner

Summer in the Upper Midwest can be nearly as brutal as winter. It is important that your central air conditioner is reliable and efficient so you can stay cool as the temperature shifts.

Central Air Conditioner

When should an air conditioner be replaced?

Generally speaking, central air conditioners should be replaced every 10 to 20 years. If you rely on your AC from spring until fall every year, you will likely need to replace it closer to the 10 year mark. If you use your AC more selectively, it could last significantly longer.
We recommend finding out the age of your equipment so that as it ages you can start thinking about when you will have to replace it and what you would like to replace it with, before it breaks down and you have to make a decision under pressure. Getting an energy audit is a great way to learn more about the status of your AC.

What should I replace it with?

If your equipment is ready to be replaced, upgrade to a high-efficiency model. Many contractors will install an 13 SEER (Seasonal Energy Efficiency Ratio) as a default option. A model with this rating is efficient enough that may qualify for a rebate — check with your utility.
Also be sure to check with your installer about whether an even more efficient model makes sense for your system. If it does, you will likely qualify for an even more efficient model with a bigger rebate. Many higher-efficiency models have SEER ratings between 14 and 16, but can go as high as 20. To understand the efficiency impact and annual savings between SEER ratings, use the calculator linked below. 
Air source heat pumps are emerging as a great alternative to central air conditioning systems because they are even more energy efficient than high-efficiency ACs, and they can also provide heat in the winter.

I don’t have central air now, can I add it?

Central air conditioners are most commonly found in homes with furnace heating systems, since both rely on ductwork to distribute heated or cooled air. If your home has a furnace but does not have central air, adding a central air system can be a pretty straightforward project.

If your home has a boiler or an electric baseboard heating system, adding central air is much more difficult, because the ductwork doesn’t already exist. Adding ductwork to an existing home is expensive and can be a highly disruptive project. In these cases, installing a high-efficiency mini-split air source heat pump is a great option!

Tuning your AC

Just like your car, an AC unit should be cleaned and tuned, in this case every few years. A common part of a “clean and tune” appointment is recharging or filling your AC with new refrigerant. The refrigerant — often called Freon — is a type of halogenated chlorofluorocarbon (HCFC), and it is an important part of how an AC cools air down.

Consider which refrigerant your AC uses

HCFCs are being phased out due to their harmful impact on the ozone layer. In the United States, production of HCFCs is scheduled to stop at the end of 2019.
Since 2019 is the last year Freon and other HCFCs will be widely available, be sure to discuss what refrigerant is used by the model you’re considering before you purchase a new AC. Make sure that the refrigerant will be available in the future when you need to recharge your AC.
If you plan to do any clean and tune work on your existing AC in 2019, first find out what kind of refrigerant your AC needs. If it uses Freon or other HCFCs, consider installing new equipment that uses a refrigerant type that will still be widely available after 2019 instead. You can talk about your options with your installer. Additionally, you are welcome to discuss this with our free Energy Advisor Service — just click the “Ask Us” button below.

What will it cost?

Most of the bids our Energy Advisors review for installing a new high-efficiency central air conditioner in Minnesota fall between $3,300 and $5,000.

outside resources

SEER savings calculator

Simple way to understand the savings associated with a higher efficiency AC

Department of Commerce — Home Energy Guide

On Page 38 of this guide you can learn more about efficient air conditioning.

Department of Energy — Common AC problems

Advice on solving common problems with central AC

Department of Energy — Central Air Conditioning

Details on choosing and installing new central AC.