Learn how long various types of AC should last. We also explain the tell-tale signs your AC is nearing the end of its life and what you can do to extend it.
The lifespan of an AC unit depends on various factors, with build quality, climate, cooling power, usage, and maintenance all playing critical roles.
You can reasonably expect air conditioners to last several years in normal operating conditions.
There are AC units out there well over a decade old, happily whirring away just as efficiently as the day they were installed.
This guide covers everything you need to know about how long air conditioners last and what you can do to make yours last as long as possible.
How Long Does the Average AC Unit Last?
Warranties usually cover the compressor for five to ten years, although portable air conditioners have a single product warranty lasting one, two, or three years.
Portable AC Lifespan
The average portable air conditioner lasts five to eight years, mostly depending on how often you move it around and how well you protect it during transit.
Humid environments also make the unit work harder, which can reduce lifespan.
Portable AC units can generate anywhere from 5,000 BTU to 10,000 BTU of cooling output, making them suited to most rooms.
Window AC Lifespan
Window AC units last ten to 20 years with annual professional maintenance, but poorly maintained units can last less than ten years.
The filter, fins, evaporator, and condenser need cleaning annually to remove dirt build-up.
With external installation and BTUs ranging from 5,000 to 15,000, window AC units deliver excellent cooling power and last longer than portable units.
Mini-split AC units last up to 25 years with proper maintenance, making them the best option for longevity.
They are ductless and have an inverter compressor that lasts longer than the compressor in central AC systems.
Mini-split AC advantages include no need for ductwork, and these systems also heat and cool, with BTUs ranging from 6,000 to 40,000.
The average lifespan for central AC is ten to 15 years, with the AC unit and ducts requiring replacement eventually.
Central AC is the most popular air-con system in homes because it cools the entire home from a centralized system.
Central air conditioners have between 20,000 and 50,000 BTUs, making them the most powerful AC units on the market today.
Overall, mini-split air conditioners last longer than central air, but central air is cheaper and is more suited to warmer climates because of the higher cooling power.
The Main Factors Affecting AC Lifespan
Climate, AC sizing, installation quality, insulation, the standard of maintenance, service frequency, and usage behavior all affect AC lifespan.
Here’s everything you need to know:
Hot and humid climates mean the AC must work harder to cool the house. For example, AC units in Florida work harder than AC units in Philadelphia.
AC units work harder in hot climates because warm air affects cooling efficiency, increasing wear and tear on the system.
When heat and humidity are higher than the AC system can manage, the cooling effect in the house is also not sufficient. This can lead to you using the AC unit on max power mode all the time, which again increases wear and tear.
Additionally, the length of hot seasons determines how many times the AC unit is used. A longer hot season means the AC is used for longer, increasing wear and tear on the parts, especially the compressor and evaporator coil.
The best way to reduce the impact of a warm climate on your AC is to help it run easier inside. You can do this by insulating your home and circulating air with an additional fan.
Of course, you can't change the weather, but you can at least specify an air conditioning system that is sufficiently powerful to cope with your climate.
6. AC Sizing
What good is an air conditioner that won't cool the room? None! The AC unit must closely match the room it is intended to cool.
We size AC units in BTUs (British Thermal Units), which refers to the AC's cooling power.
An air conditioner that is too small will not cool your rooms sufficiently, and AC that is too powerful will use significantly more energy than is needed by cooling too fast and running shorter (and more numerous) cycles.
To size an AC unit, we take the size of the room/home and match it to a BTU rating.
As a rule, air conditioners need 20 BTUs for each square foot of living space.
Here's a quick list of relevant BTUs per square foot:
- Up to 150 sq. ft – 5,000 BTU
- Up to 200 sq. ft – 6,000 BTU
- Up to 300 sq. ft – 7,000 BTU
- Up to 400 sq. ft – 12,000 BTU
- Up to 500 sq. ft – 15,000 BTU
- Up to 600 sq. ft – 18,000 BTU
- Up to 700 sq. ft – 20,000 BTU
- Up to 800 sq ft – 22,000 BTU
- Up to 900 sq. ft – 25,000 BTU
- Up to 1,000 sq. ft – 28,000 BTU
- Over 1,000 sq. ft – + 30,000 BTU
Your home might have a few other factors to consider, including high ceilings, skylights, large windows, number of occupants, kitchens, and bathrooms.
Central AC has the highest BTU rating of any air conditioning system because a single AC unit must pump cool air through a series of ducts in the house. Behind this, we have mini-split AC units (although these are powerful too).
Portable air conditioners have the lowest BTU ratings because they are mostly designed for single rooms and smaller open-plan living spaces.
When choosing a portable unit, make sure it has an "auto" fan mode to extend its lifespan.
5. Quality of Installation
Installation quality plays an important role in AC lifespan because it reduces system performance and efficiency, which increases wear and tear on the system. It also means more frequent and higher-cost maintenance.
A reputable AC installer will advise on the best location for the AC and recommend size and load based on the square footage of your home.
With portable air conditioners, your installer also needs to consider the unit's best hose length and location. Obstructions can significantly reduce the cooling performance of portable AC units, as can windows and large vents.
Some common installation problems include:
- Improper sizing or load calculation.
- Failure to calibrate the thermostat.
- Electrical issues.
- Water leaks (the most common cause is a wonky condenser pan).
- Duct leaks (caused by poorly formed joints and seals).
- Squeaky fan (indicates a fan problem).
- Whirring sound (indicates bad bearings around the indoor fan).
- Improper sizing or load calculation.
- Low airflow rates (these should be within the range mentioned by the OEM).
Central and Mini-split AC systems are a large investment, so it makes sense to do your due diligence when picking an installer.
You should only use a reputable contractor to install your air conditioner. Many manufacturers use approved installers which makes it easier to assure installation quality, but you may have to find an independent contractor.
With independent contractors, verify their qualifications and experience before committing to any work, and always get an installation warranty.
Get multiple quotes, and do not be afraid to ask questions about their installation process.
4. Insulation of Your Home
The second law of thermodynamics states that heat always moves toward cold. This means warm air is attracted to your air-conditioned home, and insulation keeps that hot air from making its way inside.
Insulation plays a critical role in AC efficiency and lifespan because air gaps, uninsulated lofts, and thin walls let the heat seep into your home, making your AC system work extra hard to cool the space.
Restricting airflow in and out of your home is key to maximizing the performance and lifespan of your air conditioner.
Traditional forms of insulation (fiberglass, cellulose) are better than nothing, but they don't form an air seal. Foam insulation is superior, so if you have the option to upgrade, do it.
In the case of portable air conditioners, you should isolate the areas you want to cool so that cold air doesn't travel too far away from the system. Close doors and windows and seal up gaps in walls and doors so your AC unit doesn't have to work as hard.
3. Standard of Maintenance
AC requires regular maintenance to function normally. Not following recommended service intervals increases wear and tear on the system, reducing its lifespan, and costing you more money in the long run.
The biggest enemy to air conditioners is dirt build-up. Air conditioners accumulate dirt across most internal parts, which, left unchecked, will eventually clog the system.
You can also do a few things to look after your air conditioner, like replacing spent air filters and bending the aluminum fins back into place.
Here's a breakdown of what it takes to maintain an air conditioner:
- Air conditioner filters – these need replacing every month or two. They are easy enough to replace yourself without an expert.
- Air conditioner coil - the air filter prevents the coil from soiling quickly, but it will still collect dirt and needs cleaning.
- Condenser – condensers have a fan that moves across the coil. It needs cleaning on the intake side annually.
- Aluminum fins – fins on the evaporator and condenser coils are easily bent out of place. Bent fins interrupt airflow and reduce system performance. They should be combed into place with a fin comb every few months.
- Condensate drains – clogged drain channels restrict the AC's ability to reduce humidity, which leads to a warmer, wetter home. Running a wire brush through the drain channels will keep them clear.
- Refrigerant – you should check coolant levels every six months. When coolant levels are low, a professional engineer needs to top them up.
- Fan blades – over time, the fan blades can work a little loose. Tightening the blades and adjusting the angle will improve system performance.
- Ductwork – central AC systems have ducts that require inspection every year to ensure there are no holes or gaps.
2. Service Frequency
All central, window and mini-split air conditioners should be serviced annually by a professional air conditioning engineer. If you live in a hot and humid location, consider an inspection service at the six-month mark.
It's good practice to schedule service intervals with a professional contractor to ensure that your AC unit is serviced on time. The best time of the year to service AC is in the spring (if you have mini-split AC, get the heating serviced in the fall).
Providing your air conditioning system is maintained properly, there is no reason why it shouldn't last over a decade.
1. Personal Preferences
How you use your AC unit plays a significant role in its lifespan. If you use it at its lowest temperature all day, you will push it extremely hard. Additionally, not circulating cold air properly makes you use the AC for longer.
Here are some common ways people unknowingly shorten the life of their AC:
- Running on maximum power for short bursts (it's better to take things slow and let the AC get up to speed).
- Running the thermostat significantly lower than outside (this increases energy consumption and makes the system work harder).
- Setting the thermostat to come on at set times (this neglects the fact that you don't always need your AC to turn on).
People's biggest mistake with central air conditioning is setting the thermostat too low, shortening various components' lifespans.
The best way to run air conditioning is to run it close to the temperature outside (around 20 degrees Fahrenheit less) and run a more powerful fan to circulate the cool air.
The addition of a fan makes an enormous difference, reducing the temperature in your home by another two-three degrees. It distributes cold air more efficiently, creating a consistent temperature.
Another benefit to using a fan is windchill -- the cooling effect of air blowing on your skin, making your home feel cooler than it is.
Setting the thermostat to only turn on when your house reaches a certain temperature (and aligning this with what makes you comfortable) will ensure the system only boots up when needed (versus when it isn't, as with set times).
Of course, there are also times when running your AC isn't worth it. If you're only a bit too warm, try moving to a lower floor level, use a fan on its own to cool down with windchill, close your window shutters, and open a window.
How to Extend the Lifespan of the Average AC
Modern air conditioners can last twenty to 25 years if looked after, and there are several ways you can extend the life of your AC, from insulating your home (to keep heat out) to closing your shutters and curtains.
The most important factor in extending the life of your air conditioner is proper upkeep and maintenance. Here are the best ways to extend the life of your air conditioning:
- Get your AC serviced by a professional air conditioning engineer and follow the manufacturer's interval recommendations.
- Replace air filters every few months (some are also cleanable).
- Top up coolant when it runs low.
- Take care of the condenser (the portion of the AC unit that sits outside the house). It needs to be clear of debris and dirt.
- With portable air conditioners, take care when moving them around. The last thing you want is to damage the internal components!
- Use the "auto" fan setting, so the fan only runs when it is actively cooling.
- Give your air conditioner a rest – don't run it all the time. You can keep the temperature in your home low by circulating air and installing insulation. Aim to run it no more than 8 hours per day.
- Set your thermostat to turn on at the desired temperature rather than the desired time so that it only boots up when needed.
- Increase insulation in your home – cavity wall insulation and PIR insulation board will create an air seal to improve your AC's efficiency.
- Circulate cold air with a separate fan, so your air conditioner fan has less work.
- Close windows when the AC is running and isolate the rooms you want to cool to reduce strain on the system.
- Use blinds or other window coverings on sunny days to block the sun's warmth and keep your home cooler.
- Set the temperature to no more than 20 degrees Fahrenheit below the outside temperature so it can catch up without using massive energy.
- Keep appliances and candles away from the thermostat. Otherwise, it might register a higher temperature and use more energy.
- Use alternative methods of cooling like electric fans and shades. Moving to a lower floor will also help you stay cool without using AC.
- If your air conditioner starts making a shrieking, whirring, or rattling noise, the fan is probably loose. Stop using the air conditioner until an engineer can fix it, or else you might cause permanent damage to the fan.
- If your air conditioner experiences a drop in airflow, stop using it. The fan is probably broken and needs replacing.
- When you eventually replace your air conditioner, have an engineer size the correct unit for your home to maximize efficiency.
Signs Your Air Conditioner is Near the End of its Lifespan
While sticking with your old air conditioner will save you money in the short term, all air conditioners need replacing eventually.
In time, you can be sure that your AC will break down and cost more to fix than it is worth.
Knowing when to replace your AC is important so you can do your research ahead of time and make a smart purchase for your home.
Here are the main signs your air conditioner is spent:
7. Your air conditioner is over ten years old
After ten faithful years, most air conditioners are due to be upgraded. While many air conditioners last longer than fifteen years, newer systems are far more efficient, cooling your home faster using less energy.
6. Your air conditioner isn't cooling like it used to
As air conditioners age, they start losing efficiency and the ability to cool air. You might notice that you need to run the thermostat lower or the air conditioner on a faster speed to cool your home as you did a few years ago.
5. Your air conditioner has weak airflow
Healthy air conditioners blow a strong, consistent stream of air. If the force from your vents is weak, your system probably needs a tune-up, but it might be worth upgrading to a newer system if yours is over a decade old.
4. Your air conditioner uses R-22 Freon
R-22 Freon was banned from production and importation in the US in 2020. If your AC system uses this refrigerant, beware that supplies are running low and will run out. R410A and R407C can sometimes be used as substitutes.
3. Your energy bills have rocketed
If your energy bills have rocketed and your AC is to blame, this could be a sign there is something wrong with it, or the system might just be old. Have an engineer inspect your system to figure out what’s happening.
2. Your air conditioner keeps breaking down
Your air conditioner shouldn't break down if it has been maintained properly. A lack of maintenance causes most AC problems, so breakdowns are a concern and could indicate a serious problem with major components.
1. Your air conditioner needs a major repair and is past its warranty
If your AC needs a major repair outside its warranty, repairing it could cost more than replacing the unit entirely.
It will be worth buying a new air conditioner, so you have a warranty and a better, more efficient system.
Lastly, if you are moving home and there is an existing air conditioning installation, find out when the owner installed it and establish the remaining warranty.
AC units can cost a lot of money, so it pays to know what you are getting yourself in for.
Good look in your search for the perfect air conditioner!