Knock out this seasonal maintenance task in about an hour
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You’ll spend a lot on supplies, but you may still save money by DIYing.
As autumn rolls around and the temperature begins to plummet, it's time to think about winterizing your air conditioning unit. Whether it’s an outdoor unit or a window AC, properly preparing your air conditioner for winter storage will help lengthen its life and ensure it stays in working order for the summer. Here’s how to winterize your AC unit with just a few simple steps.
The first step is to turn your AC off. You’ll want to do this before you move and clean the unit.
For portable or window AC units, the power toggle is easy to find and is usually near the control panel. Shut down the unit and unplug it to prep for cleaning. For stationary AC units, look for a control panel on the condenser that’s usually protected by a cover. Remove the cover, and you should find the power switch.
If you’re winterizing a stationary AC unit, it can’t be moved and you can skip this step. But portable and window AC units must be detached to safely clean and store them.
Because even portable AC units tend to be pretty big and heavy, removing an air conditioning unit is typically a two-person job. Be extra careful during this step to avoid dropping the air conditioner.
First, remove the front cover if necessary. Then, take off any insulation surrounding the AC unit. Finally, lift the unit out of the window and place it on a towel. Know that your air conditioner may leak slightly—this is normal and nothing to worry about.
If applicable, remove the base of the air conditioner. Use a screwdriver to carefully remove the base from your windowsill.
After working hard to keep you cool all summer, your air conditioner’s filter is most likely a little worse for wear. Most AC filters should be removed and either cleaned or replaced on an annual basis to improve energy efficiency. In fact, cleaning or replacing your filter can improve efficiency by 5% to 15%, according to the United States Department of Energy.
If you’re replacing your filter, go ahead and insert the new filter into the unit now, so you won’t have to in the summer. If you have a reusable filter, rinse it under running water and allow it to soak for a deep clean. Then, wipe down the AC coils and the outside of the unit with a wet rag.
If your AC unit is part of a whole house HVAC system, the filter may be located inside close to the fan assembly, but it’s still a good idea to replace it for the winter.
You’ll do a more thorough AC cleaning in the spring before turning it back on, but it’s a good idea to lightly clean the exterior of the unit now before it sits dormant for several months.
Your window AC unit may have grown dusty over summer: Keep the dust from causing problems by giving your unit a full wipe-down with a soft cloth before you store it.
If you have an outdoor unit, dust and dirt may have built up on the coils and fins, which impedes heat transfer and slows down performance. Take a wet, soft cloth and carefully wipe away any dirt buildup on outdoor components. You may have to lift off or open the unit’s frame to access components more easily.
Outdoor AC units are durable, so if there’s a lot of dirt you can bring over a hose and give it a quick rinse.
This is also a good time to clear any brushes or branches that have grown too close to your outdoor unit. You want at least a few feet of clear space on all sides of the unit for safety and performance.
If you have an older AC unit and live near the ocean, or you get a lot of rain in your area, you should also add a protective coil spray to help prevent corrosion over the winter. You can find both coil cleaner and anti-corrosion coil spray at your local home improvement store. Some also prefer to wax the outside of the AC unit for additional protection, but that’s not usually necessary.
Outdoor AC units may use copper pipes to channel refrigerant or drain condensation. Because of the damage moisture can cause when it freezes, it’s important to protect these pipes if your winters bring freezing temperatures.
If your AC unit has exposed piping, wrap it with pipe foam insulation and bind it with insulation tape to hold it in place. If you already have pipe insulation, check that it’s intact, free of tears, and covers all piping adequately.
The end of the season is a good time to conduct any necessary routine maintenance on your air conditioning unit. If your air conditioner has been experiencing any issues, get in touch with an HVAC professional near you. They can help you repair your unit and get it ready for the following summer. A professional can even help you decide if it's worth making repairs on your unit or replacing it altogether.
This maintenance is particularly important for stationary AC units and window units that use refrigerant. Refrigerants function in a closed system to absorb and move heat, but over time small leaks and wear can decrease the amount of refrigerant, creating performance problems. Professionals have the tools to measure current refrigerant levels and safely recharge systems if necessary. If it’s been a few years since your AC had this kind of inspection, it’s a good idea to schedule it now.
For a standard window AC unit, HVAC maintenance costs could be as little as $60. A full HVAC inspection will cost between $200 and $400 depending on what you want done. If a technician finds something that needs attention, such as low refrigerant levels, you can expect an extra $100 to $200 fee to put things right.
When removing a portable or window model, you’ll need to store your air conditioner for the season until temperatures climb again.
Store the unit in a cool, dry place and cover it in order to prevent it from getting dusty. Make sure that your air conditioner is elevated off the ground if you store it in the garage, and protected from pests if you store it in the attic.
If you have a stationary outdoor unit that’s part of your HVAC system, you can’t store it, but you can still protect it from the elements. That’s especially important in fall and winter, where storms bring debris, snowfall, and other problems for an AC unit.
Avoid covering the unit completely (like with a tarp or dedicated cover) if possible. Instead, it’s better to shield the top of the AC unit so that leaves, snow, and other unwanted debris can’t fall directly inside. An awning or small roof works well. In a pinch, a basic sheet of plywood can work, too. A dedicated AC cover can be helpful, but they also tend to create problems with moisture buildup, as well as encouraging bugs and pests to take up residence.
Your AC unit is winterized and ready! But if you get a lot of snowfall over the winter, it’s a good idea to check on the outdoor unit from time to time. If you get six inches or more of snow, brush off the top of your AC; otherwise, the weight of accumulated snow and ice could potentially damage the unit. Professional snow removal services can take care of this, too.
Margaret Wack contributed to this piece.
Most window AC units are designed to be removed if necessary, but some are easier to handle than others. If your unit includes fitted insulation and a screwed-in base, it could be difficult to take out. However, it’s important to remove and store it if possible: Window AC units can be damaged by harsh winter conditions, and simpler models can let cold drafts into the room.
If you really can’t remove your window AC, you can purchase a cover to help protect it. However, winter precipitation can create moisture build-up in these covers which may create additional problems.
Look up your model number online to find additional information. Usually, you can just take a look at the old filter and find the brand name and dimensions to order a new one. When replacing the filter, always check that it’s pointed the right way to match the direction of your airflow. Many filters have arrows on them to help with this step.
You don’t want to turn your heat pump off for the season like an air conditioner. Heat pumps reverse their cooling process and use it to add heat to a house in winter conditions, so they should stay on and operational. However, our other steps provide useful seasonal maintenance to make sure that heat pumps are in top condition for their winter workload. That includes cleaning and (if it’s been several years) a professional inspection to check refrigerant levels.
The outdoor portions of air conditioners are designed to weather the rain, so you don’t need to worry about it. An awning or roof will help protect them from snow or falling debris, which can do more damage. This is true of both window AC and outdoor units for larger systems.
Winterizing can still help you save money on energy costs and help prepare your AC for its work next year when you turn it back on. We suggest planning for at least some maintenance, even if winters are mild in your area.
It can be tempting to leave your air conditioning unit in your window throughout the winter, but it’s not a good idea. Removing your air conditioner and safely storing it is the best way to protect it from bad weather. It will also help to ensure that your room is air-tight and doesn’t let any cold air in.