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Switching from Air Conditioning to Heat

Oct 13, 2022

Two AC units sitting next to a brick house in the yard with technician tools resting onto of them.

Image: The Money Pit

As the temperatures begin to drop, homeowners should be thinking about how to prepare their homes for fall and the colder months beyond. Switching from air conditioning to heat is a necessary part of this transition. 


Learning how to switch from air conditioning to heat is crucial for homeowners, especially because this simple change can come with a lot of questions. You might be wondering, “When should I switch from AC to heat?” or how to switch your furnace from AC to heat. You might also be asking yourself, “What’s the best way to maintain my HVAC unit throughout the process?”


Switching your HVAC from AC to heat doesn’t have to be overwhelming. We’ll walk you through some of the basics of how to switch from air conditioning to heat, but remember that it’s always a good idea to contact a professional for an inspection if you still have any questions. 

How to Switch from Air Conditioning to Heat

When Should I Switch from AC to Heat?

If you’re hoping to find the best time to switch from AC to heat, keep in mind that it could vary from year to year. It will depend on the weather outside and how quickly the seasons change from summer to fall.


Typically, the middle or end of October is a good time to make the switch. Ultimately, it’s up to you, but it’s a good idea to have your heat turned on before temperatures start to drop below freezing. Once you’ve determined when to switch from AC to heat, you can easily begin to implement the change.

Turn Off the Air Conditioning Unit

When switching from air conditioning to heat, the first step is to turn off the air conditioning.


Then, once you’ve powered off the AC unit, you should perform some maintenance tasks to ensure your system is in good condition.


Here’s how to properly shut down your air conditioning system for the fall and winter months:

  1. Power down the unit. Find your HVAC exterior power circuit (usually mounted on the side of your house in a small box) and flip the power switch to the “off” position. Cutting the power to the AC prevents electrocution during maintenance.
  2. Clean the unit. Get rid of any debris, like leaves or twigs, surrounding the unit. Wash off any dust or dirt that has built up in the vents to keep the unit in good condition during its off season.
  3. Check for damage. Cracks, leaks, and rust can cause serious problems, so check for any signs and contact an HVAC technician if repairs are required.
  4. Cover the unit. A vinyl or plastic air conditioner cover protects and insulates your unit, which prevents damage to the internal components of your system. Air conditioner covers can be found at home improvement stores or online.
  5. Perform routine maintenance. Check your unit every few weeks throughout the fall and winter to remove debris, rainwater, snow, or ice that may accumulate.

Clean Air Ducts

As you’re learning how to switch from AC to heat, it’s necessary to do some cleaning as part of the process. Before you turn on your furnace for the season, make sure your vents are free of obstructions that may hinder your system’s ability to heat your home.


Plastic food wrappers, receipts, and even toys have all been found in home ventilation systems and can potentially cause house fires if not taken care of. The period where you’re switching your HVAC from AC to heat is a great chance to make sure your vents and ducts are clear of hazards.


It’s also a good idea to wipe down vent covers and check the vents for other debris like dust, mold, or pet hair. These contaminants can circulate in the air and cause other issues like allergies or dust buildup.

Replace Furnace Filters

Replacing the furnace filters is an integral part of all HVAC maintenance and changes. Clogged furnace filters are one of the most common causes of heating issues. Over time, dust and debris can build up on your furnace filters, forcing your heating system to work harder to circulate warm air throughout your home.


Aside from the initial filter replacement at the start of each heating season, it’s also a good idea to check the status of the filter every month or so and replace it as needed. If you or a family member suffers from chronic allergies, consider upgrading to a HEPA filter to prevent allergens from contaminating the air in your home. 

Check Carbon Monoxide Detectors

A furnace that isn’t running properly can be extremely dangerous, since they can produce carbon monoxide.


Carbon monoxide is a very dangerous gas, known as the “silent killer” because it’s colorless and odorless, making it difficult to detect in the event of a leak. It’s the second leading cause of poisoning in the U.S. 


Make sure to test your carbon monoxide detectors every few months, especially at the start of the heating season when you turn the furnace back on. To test your carbon monoxide detector, follow these steps:

  • Locate the “test” button and hold it down until you hear two beeps. Once these beeps sound, release the button.
  • Repeat the first step, this time pressing the test button until four beeps sound. Four beeps indicate that a signal was sent to your monitoring station.
  • Wait 10 to 15 minutes, then check to make sure your alarm switches from “test mode” back to its original setting. You’ll need to disconnect and reset your device if it doesn’t return to its original setting on its own.

Important note: make sure to contact your home security company before conducting a carbon monoxide detector test to prevent a false alarm. 

Schedule a Heating Inspection

Now you know how to switch your furnace from AC to heat the right way, but don’t wait until something goes wrong to call in the experts. Heating repairs or replacements should be taken care of early so you have peace of mind going into the winter. Call our HVAC experts or schedule an appointment online today. 


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