Neglecting your AC unit can lead to decreased efficiency, higher energy bills, and even costly breakdowns. To avoid these problems, you should keep up with simple maintenance tasks like changing your air filter, cleaning your vents, clearing debris from your outdoor unit, and more. Whether your existing AC is in need of upkeep or you’re in the market for a new one, read on for tips to stay cool.


Friendly American Standard HVAC technician, who is wearing a cap, smiles, holds a clipboard, and stands beside a condenser unit
A heating and cooling specialist should check your air conditioner at least twice a year.

How to Maintain Central AC Units

First, let’s talk about maintenance. While many homeowners have an air conditioner, they don’t necessarily know the ins and outs of performing regular maintenance on it.

Why is regular AC maintenance important? By maintaining the system, you will extend the life of the unit, and your home will remain at a comfortable temperature without an uncomfortably high energy bill.

Schedule Annual Routine Maintenance

For central air conditioning units, the best way to keep yours working properly is to have it serviced bi-annually by a trained HVAC professional. They will take care of the many items related to maintaining the unit and be able to perform any necessary repairs or “tune-ups.”

Replace Your Air Filter

Replacing your HVAC filter regularly is one of the simplest yet most important maintenance tasks. A dirty, clogged filter restricts airflow and makes your AC unit work harder. Check your filter monthly and replace it at least every 3 months or more often if you have pets or allergies.

Keep Vents Clean

Make sure to keep your floor vents clean and unobstructed. Dust and vacuum the vents regularly to prevent dust and grime buildup. Avoid placing furniture, curtains, or other objects in front of the vents, which can block airflow.

Clean Evaporator Coils

The evaporator coils absorb heat from your home’s air. Over time, they can get coated with dust and grime, reducing their ability to effectively remove heat from your home and create cool air. Carefully clean the coils (located in the air handler) with a soft brush and spray with a no-rinse coil cleaner annually.

Check for Leaks

Inspect your AC unit and connections for any signs of refrigerant leaks. Leaking refrigerant is bad for the environment and will cause your AC to blow warm air and eventually stop working. If you spot any leaks, ice buildup, or hear hissing noises, call in an HVAC contractor for repair.

Clean Outdoor Unit

You need to keep your AC’s outdoor unit (condenser) clean and free of debris like leaves, grass clippings, twigs, and dirt. Trim back any plants at least three feet from the unit. Gently spray the exterior with a hose to remove buildup from the condenser coils, but avoid using a pressure washer, which can damage the delicate fins.

Shade Outdoor Unit

If your outdoor condenser unit is in direct sunlight, it has to work harder to release heat. Providing some shade, either from trees or a built structure, can help it run more efficiently. Just be sure to maintain at least three feet of clearance around it.

Use Smart Thermostat

Upgrading to a smart programmable thermostat allows you to set cooling and heating schedules, remotely control your AC, learn your preferences, and optimize performance for the best efficiency. When your air conditioning system works more efficiently, it experiences less wear and tear. So, installation a smart thermostat is akin to preventative maintenance.

Routine Professional Duct Cleaning

While you can clean the visible portions of your ducts yourself, it’s a good idea to have a professional clean them thoroughly every 3–5 years. This removes built-up dust, debris, and potential mold growth that can impact your indoor air quality and air conditioner efficiency.

For more information, read: 5 Easy Air Conditioner Maintenance Tips


How to Maintain Window, Portable, and Wall AC Units

If you have window or portable AC units, the most important maintenance step is to change the air filter regularly, just like with a central air conditioner.

Most window units have a simple filter in the front grill area. Clean it once a month during the cooling season and replace it if it has any holes or appears worn.

Also, clean the air conditioner properly by vacuuming around it to remove any dust and dirt that can clog up the unit and cause it to malfunction.

During the off-season, take the unit out of the window and store it in a dry location. If you must keep the unit in the window, cover the part that is exposed to the outside.


Choosing a New Air Conditioner

If your cooling system is more than 15 years old, it may be time to purchase a new system. Do a little homework to get the best AC brand and unit type for your needs and keep energy costs to a minimum.

There are various types of units to choose from, including window, portable, through-the-wall, and central.

Here’s a quick rundown of each type.


Friendly American Standard HVAC technician, who is wearing a cap, smiles, holds a clipboard, and stands beside a condenser unit
Central air conditioning is a popular choice, but matching the right-size unit with your home is crucial.

Central Air Conditioners

When it comes to choosing a central air conditioner, there are many factors involved, such as the size of your home, its number of windows, and the amount of insulation.

Air conditioning contractors can determine the correct system for your home. To choose one, check references, ask questions about warranties (limited vs. extended), and get several bids.

Once you’ve selected a contractor, they will determine the correct size and type of system for your home.

You might hear these terms when buying an air conditioner:

  • Seasonal Energy-Efficiency Ratio: This rates how many British thermal units an air-conditioner will remove for each watt of electricity consumed. The higher the SEER and SEER2, the less you will spend on operating costs. Federal law mandates a minimum of 15 SEER (14.3 SEER2) for the northern states and 15 SEER (15.2 SEER2) in the southern states for all new air-conditioning units.
  • AC Tonnage: A cooling ton in an air conditioner equals 12,000 BTUs per hour. That means a three-ton air conditioner can remove about 36,000 BTUs of heat per hour from your home.
  • Annual Fuel Utilization Efficiency (AFUE): This estimates how much heat a furnace delivers for every dollar spent on fuel. The higher the AFUE, the lower your heating bills.
Window air conditioner unit mounted directly in a window.
A window air conditioner unit mounts right on the window. (©tanvirshafi, Adobe Stock Photos)

Window Units

When choosing a window unit, the most important factor is the size of the room you wish to cool and the cooling power, measured in British thermal units, of the unit you choose.

Here’s a general guide for window air conditioners based on room size:

  • 12′ x 12′ room: 5,000 BTU unit
  • 16′ x 16′ room: 7,000 BTU unit
  • 20′ x 20′ room: 10,000 BTU unit
  • 24′ x 24′ room: 14,000 BTU unit

In addition to size, make sure the AC unit you buy:

  • Has an EER (Energy Efficiency Ratio) of 11 or higher
  • Carries the EnergyStar label
  • Has a low noise rating
  • Provides good airflow
  • Uses a permanent or reusable air filter
  • Has various speed settings

Related: How Much Does It Cost To Run A 8000 BTU Air Conditioner?


Portable, ventless air conditioner rolled up beside a bed with a spread hanging down and tassels touching the hardwood floor.
Portable air conditioning provides a zoned, efficient option for cooling small spaces. (©Axel Bueckert, Adobe Stock Photos)

Portable AC Units

A portable air conditioner is basically AC on wheels. It has an exhaust tube, which must be vented outside to remove hot air from the room.

Portable AC systems don’t require permanent installation. In fact, they come with wheels so can move them from room to room. Most of them come with a window venting kit that allows you to prepare a window for the exhaust tube.

These systems accumulate moisture, and you’ll need to routinely drain them. This means emptying a reservoir on the unit or hooking up a drainage hose if compatible with the unit.

Before purchasing a portable AC, consider its energy efficiency. Systems with dual hoses cool rooms faster than their single-hose counterparts.

Read also: What is a Floor Air Conditioner?


Through-the-Wall Units

You often see through-the-wall AC units in hotel rooms, but they’re also ideal for large open rooms, studio apartments, or remodeled garages.

You can use through-the-wall units in rooms that aren’t connected to a central air conditioning system. They’re ideal for home additions and, really, wherever you want to add AC without running ductwork.

You can purchase these units with heating and cooling features or just cooling features, and you must carefully choose where to install them.

You must install these units in exterior walls where there’s no plumbing or electrical wiring. In addition, you’ll need to install a sleeve or chassis that can support the weight of the air conditioner.

A mini-split ductless air conditioner is one type of through-the-wall system, but it’s not boxy and comes with a separate outdoor unit. Mini-split AC units are sleek, subtle, and look good in any home. If you are interested in this type of AC, take a look at our ductless AC unit cost guide.


Consider A Warranty

If you’ve ever been curious about what a home warranty entails, here it is: A home warranty plan safeguards the appliances and essential systems within your residence, encompassing major home appliances, electrical components, plumbing, and HVAC systems. In contrast to your homeowner’s insurance policy, which provides coverage for specific perils, a home warranty operates as a service agreement that addresses the effects of regular wear and tear.

So, If you are worried about your air conditioning unit breaking down due to normal wear and tear, consider investing in a homeowner’s warranty.

A review team independent of Today’s Homeowner picked out the best homeowner warranty providers, though they also looked at smaller companies such as Fidelity National Home Warranty, Global Home USA Warranty, and A.B. May Home Warranty.


Final Thoughts

Regular air conditioner maintenance keeps your AC running efficiently and your home comfortable and helps you avoid costly repairs. You should keep up on these DIY maintenance tips, including changing your air filter, keeping your unit clean, and using a smart thermostat to prolong the life of your AC system. I recommend that all homeowners schedule professional annual service and stay alert for any warning signs that your AC needs attention.


Further Information

Frequently Asked Questions

How often should I replace my AC air filter?

I recommend checking your furnace filter monthly and replacing it when it looks dirty. Typically, home air filter last 1–6 months, depending on the filter type, filter thickness, and the air quality in your home/area.


Should I cover my outdoor AC unit in the winter?

Although it isn’t necessary to cover your AC unit, I still recommend doing so. I recommend using a cover designed for outdoor AC units as opposed to a tarp.


What temperature should I set my AC to in summer?

Most HVAC pros recommend setting your thermostat to 78ºF in the summer while you’re at home. When you’re not home, put it a few degrees higher to lower your electric bills.


Article Update Log
6/17/2024
Reviewed for accuracy, cost data, industry best practices, and expert advice by Jonathon Jachura.
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Danny Lipford

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Danny Lipford is a home improvement expert and television personality who started his remodeling business, Lipford Construction, at the age of 21 in Mobile, Alabama. He gained national recognition as the host of the nationally syndicated television show, Today's Homeowner with Danny Lipford, which started as a small cable show in Mobile. Danny's expertise in home improvement has also led him to be a contributor to popular magazines and websites and the go-to source for advice on everything related to the home. He has made over 200 national television appearances and served as the home improvement expert for CBS's The Early Show and The Weather Channel for over a decade. Danny is also the founder of 3 Echoes Content Studio, TodaysHomeowner.com, and Checking In With Chelsea, a décor and lifestyle blog.

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Jonathon Jachura

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Jonathon Jachura is a two-time homeowner with hands-on experience with HVAC, gutters, plumbing, lawn care, pest control, and other aspects of owning a home. He is passionate about home maintenance and finding the best services. His main goal is to educate others with crisp, concise descriptions that any homeowner can use. Jon uses his strong technical background to create engaging, easy-to-read, and informative guides. He does most of his home and lawn projects himself but hires professional companies for the “big things.” He knows what goes into finding the best service providers and contractors. Jon studied mechanical engineering at Purdue University in Indiana and worked in the HVAC industry for 12 years. Between his various home improvement projects, he enjoys the outdoors, a good cup of coffee, and spending time with his family.

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