Central Air vs Window ACs – Cost, Efficiency, Comfort, Convenience

Central Air vs Window ACs

The central air vs window air conditioners question is important to consider before deciding where to invest your money.

Cost, Convenience, Comfort and Climate

Central air costs much more than multiple window ACs, but in terms of convenience and indoor climate comfort, central air conditioning is the better choice. That’s the bottom line, but here’s where we are going on this page.

We compare window air conditioning to central air conditioning in all major categories including cost to buy, cost to run, maintenance requirements, indoor climate control, convenience features, climate considerations and more.

We’ve listed the central AC vs window AC in the order of highest interest to lowest to most readers – but use the Navigation to find the topics of greatest importance to you!

The first half of the page is heavy on every aspect of cost – cost to buy, cost of ductwork, cost to run, cost to repair. Then, we move to indoor comfort, convenience, climate and related topics.

The Hassle Effect

There is built-in hassle with using multiple window air conditioners rather than one central AC manually controlled by a thermostat or an app on your phone. And if you don’t turn on a window AC in a hot room ahead of time, it won’t be comfortable for the first 15-45 minutes you use it depending on how hot and humid the room is at the start.

Decision-making Tip: Always keep the hassle level in mind as we go through the process of determining the right choice for your home.

Cost to Buy – Compare Window AC and Central AC Prices

$10,000 for central air vs $429 to $800 per window AC!

The US national average cost of central air conditioning installed is $7,900 to $11,900, or an average of about $10,000.

The average cost of a good 12,000 BTU window air conditioner (500 square feet of coverage) is $429, or 1/18 to 1/28 the price of central AC. Does that settle it?

That’s an eye-opener that makes you wonder whether investing in central air is worth the much higher cost. But for most consumers, there are additional considerations.

How many window ACs? For starters, how many window air conditioners would you need? Most homeowners want at least two in a smaller home – up to about 1,200 square feet. One goes in the main living area and another goes in the bedroom.

But most people, if they go the window air conditioner route to cool the entire home, choose 3-5 units minimum to adequately cool their home.

To determine cost, first figure out:

1). # of Rooms: What rooms you want an AC in (living room, kitchen, bedrooms, home office are favorite options)

2). Room Sizes: What each room’s square footage is – measure length x width to get square feet

3). AC Size for Each Room: What’s the right size for each room? Use our chart below or our AC Size Calculator to determine AC sizes – plug in your room sizes, one at a time, in the House Size box. Answer the Sun and Insulation questions, and you’ll get the right size window AC for each room.  

If it is easier for you, use this sizing chart.

Area To Be Cooled (square feet)Capacity Needed (BTUs per hour)
100 up to 1505,000
150 up to 2506,000
250 up to 3007,000
300 up to 3508,000
350 up to 4009,000
400 up to 45010,000
450 up to 55012,000
550 up to 70014,000
700 up to 1,00018,000

4). List Sizes: Make a list of the sizes using the calculator

5). Costs: Use the chart below to total up the cost of all the window air conditioners you’ve listed

AC Size in BTUsAverage Cost Range
6,000$199 to $259
8,000$279 to $369
10,000$349 to $429
12,000$379 to $439
14,000$449 to $529
15,000$459 to $579
18,000$589 to $739
21,000$669 to $849

Upfront Cost: Even if you buy 5 average-sized window ACs, your central air conditioning cost for equipment is still going to be much higher, in all likelihood.

Long-term Cost: If you like to plan long-range, consider one more factor: You will probably have to replace all the window units before you have to replace central air conditioning.

Upfront Cost Winner: Window air conditioners

Cost to Install – Central AC Installation Costs vs Window AC Installation Cost

$2,800 vs $0 – Unless you hire someone to install it at $75 to $200 per unit.

The cost advantage for window air conditioners continues as we discuss labor charges to install the units.

We included installation costs in the $7,900 to $11,900 range above, because more than 95% of homeowners have a pro install their central air conditioning system.

But if you want the labor cost part of that estimate, it’s $2,100 to $3,700 based on system size, where the equipment is installed, length of refrigerant lines, amount of refrigerant and general difficulty of the job. The average labor part of the invoice is about $2,800.

And almost all homeowners install their own window AC or have a family member or friend do it for free. Cost: $0! However, if you hire a handyman service to install your window ACs, expect a cost of $75 to $200 per unit. Cost factors include how large/heavy the AC is, whether it has to be taken upstairs and whether the installer gives it a thorough cleaning before installing it, which is a good idea if it hasn’t been cleaned recently.

Installation Cost Winner: Window ACs

Ductwork Cost

If you’re building a home or your current home has no ductwork, then you’ve got to consider the cost there too. Complete ductwork ranges from about $3,000 to $4,700 for most 2,800 square foot homes, the average size being built these days.

Total Equipment and Installation Cost

About $3,250 for 5 window air conditioners vs $10,000 to $15,000 for central air.

At most, you might be charged $1,000 to install 5 window air conditioners. And if you pay an average of $450 per unit, or a total of $2,250, then your total costs would be at $3,250, still only about 1/3 to 1/4 the cost of central air conditioning installed, which we’ve said averages around $10,000.

If you need to install ductwork too, your total central air cost rises to around $15,000, on average, and that makes window air conditioners, from a cost perspective, that much more attractive.

Total Equipment Cost Winner: Window ACs

Efficiency & Cost to Operate – Energy Costs from Running the AC

This section looks at raw efficiency numbers plus the obvious truth that an average 18,000 BTU window AC simply won’t use as much electricity as a 48,000 central AC.

Efficiency Ratings – Window AC vs Central AC

In pure efficiency terms:

Most Efficient: The highest efficiency ratings for the most efficient central air conditioners is higher than the highest efficiency ratings for the most efficient window air conditioners. So, if you are going to buy the most efficient air conditioner money can buy, you’ll get higher pure efficiency with the central AC. But…read on!

Average: The average efficiency ratings of Energy Star certified window air conditioners are slightly higher than those for central ACs. That surprises a lot of people.

The efficiency rating systems are a little complex. Central ACs are rated in EER and SEER. Window units are rated in CEER, but not the other two.

So, best head to head ratings are considered when using EER (Energy Efficiency Ratio) for central air conditioning and CEER (Combined Energy Efficiency Ratio) for window ACs are used.

*CEER takes into account the fact that the AC is using a little bit of energy when it is plugged in but not running – when it is on standby. So, CEER is slightly lower than EER for the same AC – though most don’t give you both the EER and CEER rating, which makes it a little harder to compare.

EER of Central ACs (aka CACs) – Energy Star: 12.5 to 15 EER

CEER of Window ACs (aka WACs) – Energy Star: 13.8 to 15.7 CEER

The winner in pure efficiency is an Energy Star certified window air conditioner! It isn’t a huge difference, but that’s what the numbers show!

Total Energy Use

There are two ways to approach this.

Strategy 1: Running All Window ACs at Once

This is often the best strategy for window AC use in hot and humid climates and when you have a large household and most rooms are occupied throughout the day.

If you’re going to have all the units on whenever you would normally run AC, then add up total BTUs of the window units on your list above. For example:

  • Living room: 18,000 BTU AC
  • Kitchen: 10,000 BTU AC
  • Bedroom 1: 8,000 BTU AC
  • Bedroom 2: 8,000 BTU AC
  • Home Office (or den/bonus room): 12,000 BTU AC

That’s a total of 56,000 BTU for about 2,500 square feet of space.

A 2,500 square foot home would need a 48,000 to 54,000 BTU central air conditioner, so it isn’t that much difference.

Research Tip: Use our detailed Central AC BTU Calculator – What Size Unit Do I Need, for the most exact sizing of your AC system.

Strategy 2: Running ACs Only in Occupied Rooms

In climates that aren’t as terribly hot or humid, this approach makes sense.

You will use less energy this way, but perhaps not as less as you might think. Why not? Because rooms that are allowed to heat back up when the AC is turned off, are harder to cool down. And they might be humid too, which means you need to cool the air to a lower temperature to make it comfortable.

Still, over the course of the warm season, you will use less energy by turning room / window air conditioners on and off as you use the room and exit the room.

Cooling Tips: If you want a room comfortable when you enter it, turn on the window unit 30 minutes before you plan to use the room – like in a kitchen before you plan to start food prep or in a bedroom before going to bed. Most window air conditioners are digital and have 24-hour timers, so you can set the timer to start the AC in time to cool the air before you use the room. If you work from home, you can set the timer to start the AC in your home office before you arise to start your day.

The Ductwork Factor

Ductwork is expensive. And it raises energy use and cost.

Why? Two reasons: The ducts are sometimes run through warm places like an attic, so the cooled air is slightly warmed by the air around the ducts. And most ducts have some air leakage – cooled air leaking into spaces where it does no good.   

How bad is it?

The US Department of Energy / Energy Star states that “about 20 to 30 percent of the air that moves through the duct system is lost due to leaks, holes, and poorly connected ducts.” Plus, as noted, when the ductwork is in a warm space, the cooled air coming out of the air handler is naturally warmed by the heat in the attic.

That’s pretty bad news for central systems – and another positive checkmark for window ACs.

You can reduce energy loss in ductwork – and we highly recommend it – by:

Total Energy Use and Cost Winner: Window ACs – If you use window ACs wisely – not running all of them all the time – you will cut energy use and cost compared with central air conditioning.

Cost to Repair & Maintain

See our HVAC/Central AC Repair Guide for what can go wrong and how much it costs to fix it.

In a nutshell, here’s what you can expect in central AC repair:

Minor RepairsAverage RepairsExpensive RepairsHourly Rate
$100 – $175$285 – $500$750 – $2,000+$85 – $150

How much does it cost to repair a window AC?

Most of them are never repaired. First, it is hard to find a repair shop that takes window air conditioners.

Secondly, if you can find service, the cost of repairs is usually half the cost of a new AC to MORE than the price of a new AC. So, people usually buy a new one.

Note – A quality window unit lasts 6-12 years depending on how heavily it is used – Consumer Reports says 8 to 10 years, which is pretty accurate too. A central AC lasts 15 to 20+ years when well maintained. So, factor that into your total cost equation. You will have to replace window units, most likely, 5-10 years or more before replacing a central AC system.

Cost to Maintain

If a window AC is ever cleaned, it is likely done by the owner and not by a service technician – for the same reasons they aren’t repaired. But your AC will last longer if you clean the coils every year to every three years. There are tutorials online that show how to clean a window AC to keep it running reliably and efficiently.

Some homeowners clean their own central ACs, and there are videos for that too. But in our opinion, it makes more sense to hire an AC technician who knows how to do it and can check for minor issues – and fix them – before they become major repairs. The cost of annual AC cleaning and tuning ranges from about $150 to $400 based on how much equipment is worked on. We recommend having your central HVAC system serviced every year to every 4 years based on how heavily it is used.

Repair & Maintenance Cost Winner: Window ACs

Indoor Comfort – Climate Control

The price comparison didn’t go well for central air conditioning.

But here is where the tide turns a little. Central air produces better indoor comfort – what we often call climate control.

Whole House Temperature Balance

Central ACs offer balanced temperatures from room to room and through the entire house. Sure, the rooms furthest from the air handler, especially in a sunny upstairs room, might be a few degrees warmer than other rooms.

Temperature Balance in Each Room

Again, the balance is good with central AC. Yes, if you’re sitting near an air grate, the air might be a little cooler. But with good airflow in your home, it won’t be much different. With a window AC, the air closest to the unit will be 5-8 degrees cooler than air in the room distant from the AC, especially when the unit is first turned on in a warm room.

Humidity Control

In general, central AC systems remove more moisture from the air than window ACs. This makes the air more comfortable.

So, while it is tempting to get an oversized window AC to make sure it does the job, resist the urge. It will produce chilled but humid air – the room will feel cold and clammy.

Use the Chart above to buy an AC for each location in your house that fits the number of square feet it will cool. You will be more comfortable!

Air Filtration

Window AC filters are pretty cheap. They might collect big stuff like pet hair. But they don’t trap allergens and pollutants.

You have a lot more options with AC/HVAC filters. Even the cheap ones do a better job of removing dust and other stuff from the air you don’t want to breathe. Our Guide to AC Filters will help you select the right filter for your system.

Noise Levels

Most central air conditioners run somewhere between 60 to 77 decibels – but the unit is outside, and your windows are closed if the AC is running. So, the sound indoors isn’t too bad. Mostly all you hear is a dull hum of the outdoor unit or a short “buzz” when it starts up, if you’re sitting by a window near where it is located. The sound of air flowing through the ducts and grates isn’t loud.

Window ACs run anywhere from the low 40s to mid-60s in decibels, but they are right there in the window, and most of the noise is not blocked by the side panels. So obviously, window air conditioners are noisier. You can eliminate some of the noise with a Midea U-Shaped AC or the Soleus Air Saddle AC, because the window can be closed further. Both are on our Quietest Window AC list.

Indoor Climate Control Winner: Central cooling offers significantly better indoor climate control than window units in terms of comfort, indoor air quality and noise level.

Climate Considerations – Which is Best for Where You Live?

We have said that one potential advantage of using multiple window air conditioners vs central air conditioning is that you can use them to cool only the rooms being used. One or two window units use less energy than whole-house central AC.

Northwest, West Coast, Rockies, Upper Plains & Midwest, Mid-Atlantic, New England

In moderate and cooler climates where summer temperatures and humidity are not as high, then sure, cooling only rooms in use – or those soon to be in use – is a cost-effective way to cool. Yes, you’ll have to do a little more work to turn ACs on and off, set their timers to turn on the ACs a little before you want to use a room, etc. – Remember the Hassle Effect!

Everywhere Else

The hotter and more humid your climate, the more it makes sense to choose central AC over window ACs. In the super-hot desert Southwest and in the hot, humid South and Southeast, your entire home will be uncomfortable during much of the day without AC, especially in the afternoon and into the evening.

The best approach to operating cost, comfort and certainly convenience in very warm parts of the country is to have central air running.

Climate Concerns Winner: Even – it depends on where you live.

Environmental Concerns – Efficiency, Global Warming and Ozone Depletion

All central air conditioning systems use R410A refrigerant, aka R410-A.

Most window ACs use R410A too, but a few use next-generation R32.

First, neither refrigerant is a problem if it doesn’t leak out. ACs don’t emit used refrigerant like cars emit gasoline exhaust. 

When might refrigerant leak? The danger occurs during initial charging of the system, if a refrigerant line or coil breaks during the life of the AC and when the refrigerant is being recovered from an AC that is no longer in use. And these events do occur, especially failure during use of the AC.

The potential danger of refrigerant is measured in two ways:

1). Ozone Depletion: Both are OK for ozone: If leaked, neither refrigerant destroys ozone in the upper atmosphere.

2). What about global warming? R32 has one advantage over R410A – R32 has a much lower global warming potential, GWP, should it happen to leak.

R32 has a GWP of 771. It had been rated at 675, but through testing done in 2020 and 2021, the GWP rating was increased to 771. But 675 is the number you’ll still find in most literature. R410A has a GWP of 2,088.

Winner: R32 has a GWP about 63% lower than R410A, so if you buy a window AC with R32, the potential GWP is lower. This Energy Star rated Frigidaire AC in several size options is an excellent choice for an R32 window AC. 

Smart Home ACs

All central air conditioning systems can be controlled by voice (Alexa, Google) or WiFi if you choose a thermostat supporting those technologies.

A small but growing percentage of window ACs can be controlled by voice or WiFi. A couple good options are the 6,100 BTU GE Profile AC and the Soleus Air Saddle AC in 6,000, 8,000 and 10,000 (with heat too) models.

Smart Home Winner: Central Air Conditioning

Space Issues

OK, it’s a minor consideration in most homes. But if you don’t have a basement, attic or utility closet where an indoor air handler for central AC can be placed, then you’ll have to give up living space for it. Yes, a package HVAC system is an option, but you’ll still need ductwork for it, and the efficiency and durability of a package system aren’t as good.

Window ACs take up much less room, obviously, though there is one thing to consider: What about when you’re not using the ACs? They’ll have to be removed from the window and stored somewhere.

Space Winner: There is no clear winner because of the storage space needed for window air conditioners not in use.

Conclusions: Cost – Comfort – Convenience – Climate

If cost to buy, operate and maintain is not a concern for you, then central air conditioning is your best choice. Your home’s indoor climate will be more consistent and comfortable.

Where finances are a big part of your decision and you’re OK with the inconvenience and occasional warm room you get by using window air conditioners, then choose window ACs for your home. This is especially true in climates that aren’t blistering hot or horribly humid. 

Written by

Rene has worked 10 years in the HVAC field and now is the Senior Comfort Specialist for PICKHVAC. He holds an HVAC associate degree from Lone Star College and EPA & R-410A Certifications.

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