Central Air Conditioner Buyer’s Guide: Expert Advice

Central Air Conditioner Buyer's Guide: Expert Advice

Are you thinking about forking out for a new central air conditioning system?

A typical U.S. HVAC system in the US will cost anywhere from $5,000 to $12,500. So it’s good that you’re doing your research!

Granted, that’s for heating and air conditioning, but it should give you an idea of why making a wise choice is so important.

This article will take you through everything you need to consider if you’re looking for a central air conditioner. The different types of central air conditioners, what to consider before you purchase, and some insight into making the right choice.

Before you pull your credit card out of your wallet to finalize a purchase, ensure you’ve reviewed all the information below.

Ready? Let’s dive in!

Why trust us? This article was written by Craig Anderson and Alan Stephens.

Craig has helped thousands of homeowners repair their appliances since 2016.

Alan is one of our resident appliance experts with 20+ years of experience. He holds triple HVAC certifications in North Carolina, and, since 2004, has operated his own business, Eco Green Air Inc.

Types of Central Air Conditioners

Central Air Conditioner external unit
Split-System Air Conditioner

There are two basic types of central air conditioners, which either come as a single packaged unit or a split system. If you live in the typical North American suburban home, you likely have — or will need — a split system, so we’re focusing on this.

Split-System Central Air Conditioners

A split-system central air conditioner is exactly that — split. Part of the unit is in the home, and part of it is outside, with the two units connected by copper tubing.

The outside unit houses the compressor, condenser coils, and fan. The inside portion has an evaporator coil and an air handler that pushes air through the ductwork in your home.

As mentioned above, Split-System Central Air Conditioners are one of North America’s most common types of residential cooling solutions — assuming you live in a house.

Split systems are further broken down as follows:

  • Single-Stage: Single-Stage central air conditioners have a single-stage condenser, meaning it’s either off or running at full capacity. On an energy efficiency scale, the Single Stage AC type wouA.C. rank lowest.
  • Dual-Stage: Moving up a step, a Dual-Stage air conditioner can run at low and high. On more temperate days, which some estimate to be around 80% of the season, your air conditioner runs at the lowest stage, conserving energy. On extremely hot days, the unit will kick into high gear, using more energy and working harder to combat the outdoor heat. A Dual-Stage Air Conditioner is more energy efficient than a Single-Stage one.
  • Variable Speed: Finally, a variable-speed air conditioner continues to run throughout the day, working to maintain your set temperature without shutting off.

While a variable speed model is the best option for efficiency, it needs to be part of a matched system. In other words, all components of your HVAC system — the furnace, the air conditioner, the air handler, the thermostat, and so on are designed to work together by the manufacturer.

Packaged Unit Central Air Conditioners

Packaged unit Central Air Conditioners have all their components together in a single unit. The condenser, the compressor, the fan, and the blower. Packaged units are typically installed on the roof or a concrete slab beside the foundation of a house and are also often used in small commercial buildings.

Just like a split system, Packaged Central Air Conditioners need to be attached to a home’s ductwork, but in this case, they are connected through an exterior wall or the roof.

Central Air Conditioner Purchase Considerations

Central air conditioners cost thousands of dollars. And the price increases the larger your home and the more features you want. Then you have the additional costs of permit fees and labor. Not to mention the cost of running the units.

Do your due diligence upfront and save yourself from a costly mistake.

Here’s a list of everything that needs to be considered.

Size of Your Home

Considering the size of your home to pick the right Central Air Conditioner is key. You can find many “rules of thumb” detailing approximately how many BTUs you’ll need for a given space. But keep in mind that the numbers below are merely approximations. Make sure you pay attention to the following sections as well.

Check out the following table to save you from looking elsewhere for some rules or guidelines.

If you want to do some of your own calculations, you can do so by multiplying the number of square feet in your home by 20 BTUs. So if you have a 1,500-square-foot home, my usual advice is to take 30,000 BTUs as your baseline.

AC Size (Tons/BTUs)Square Footage
1.5 tons / 18,000 BTUs600 to 1,000 sq ft
2 tons / 24,000 BTUs1,000 to 1,500 sq ft
3 tons / 36,000 BTUs1,500 to 2,000 sq ft
4 tons / 48,000 BTUs2,000 to 2,500 sq ft
5 tons / 60,000 BTUs2,500 to 3,300 sq ft


Climate Zones Map
Climate Zone Map / Source: U.S. EnergyU.S.ormation Administration

Now that you have a baseline, your climate is next to consider.

A local HVAC installer or salesperson should do a load calculation to determine the exact amount of BTUs needed based on the size of your home, your climate, and other environmental factors mentioned below.

The map linked above will let you know what climate region you live in if you’re in the US. If you’U.S in Canada, refer to the following table.

Canadian LocationClimate Region
On the West Coast and south of the northern tip of Lake Michigan  Marine
South of the northern tip of Lake MichiganCold
Between the northern tip of Lake Michigan and the southern tip of Hudson Bay  Very Cold
North of the southern tip of Hudson BaySubarctic / Arctic

The hotter your climate region, the more BTUs you’ll need above the baseline table. If you live in one of the hottest regions, a ballpark calculation is to multiply your square footage by 10 to 15 to come up with a more accurate cooling capacity number.

But there’s more than just your climate region!

Environmental Factors

You need to consider your personal environmental factors in addition to factoring in your climate region when sizing a central air conditioner.

Energy Star provides some excellent information regarding environmental factors.

Heat gain is factored into the load calculation, which is done to determine the size of your air conditioner. Several things contribute to heat gain or loss.

  • Homes that are heavily shaded or in direct sunlight.
  • The number of windows that face the sun or face away from it.
  • The number of people living in the house.
  • The number of appliances and electronics that produce heat.

Anything mentioned above can either increase or decrease the necessary cooling capacity. In my opinion, if your house is situated in a heavily treed area that blocks direct sunlight on your roof or windows, you could theoretically get a smaller-sized air conditioner.

Cooling Capacity (BTUs/Tons)

With all the above information, the size of your home, your climate region, and your environmental factors — you’re ready to calculate cooling capacity.

The formula looks something like this.

Square footage + or – climate region considerations + or – environmental factors = cooling capacity (BTUs/Tons).

Remember, while there are several websites with charts telling you how many BTUs you need based on how many square feet you have, if you don’t know the corresponding climate region, you don’t know enough for a proper calculation.

Only you, or better yet, an HVAC professional, can properly size your equipment. And most professionals will estimate BTU requirements using the Manual J calculation, an HVAC load calculation that determines buildings’ heating and cooling capacity.

There’s no law that says you can’t use the formula above yourself to determine cooling capacity. However, I always tell homeowners to tread carefully, as choosing the wrong size air conditioner can be costly. Here’s why:

  • Oversized air-conditioners: Typically, an oversized air conditioner short cycles, which means it powers up and down more times than it should during the day, using more energy and costing you more. And since you’re overworking the air conditioner, that also reduces its life expectancy.
  • Undersized air-conditioners: An undersized air conditioner is overworked as well. Since Air Conditioner has to work harder to bring your home down to your desired set temperature, it doesn’t go through a healthy series of cycling. Like oversizing, undersizing adds needless wear and tear to your system and reduces lifespan.

Additionally, an undersized air conditioner can eventually burn out your motor or cause the evaporator coils to freeze over. You’ll also spend more on energy costs as it struggles to cool your home.

Energy Efficiency & SEER

If you’re looking for HVAC equipment, you’ll see the word SEER, which stands for Seasonal Energy Efficiency Rating. And as of January 1, 2023, SEER was updated to SEER2.

SEER or SEER2 measures cooling efficiency using a formula that takes the cooling output of a typical cooling season and then divides it by the total energy output within the same timeframe. The change between SEER and SEER2 is in the amount of static pressure used in the testing procedure, which impacts the minimum energy efficiency required.

The higher the SEER2 rating on an air conditioner, the better its energy efficiency. Also, note that the minimum SEER2 standards in the US depend on oU.S.your region.

RegionMinimum Seer @ < 45,000 BTUMinimum Seer @ >/= 45,000 BTU

In terms of what’s the best SEER2 rating for your home, there is no finite answer. A good SEER rating is unique to each home.

And it may not be worth it to pay the price of a higher SEER2 air conditioner. For example, those who live in a temperate region and don’t suffer from much humidity could opt for a unit with a lower SEER2 rating.


As with most appliances, central air conditioners have various additional features, but few are necessary, and you’ll just pay extra to use them.

It’s up to individual homeowners to determine whether or not a feature is worth the price. From what I’ve seen, not having a specific feature can be a dealbreaker for some people, whereas others just want to stay cool inside their homes.

Here are some possible features you can find on central air conditioners:

  • Smart technology. Smart technologies enable you to communicate with your air conditioner via phone or home network. If you have or are interested in getting a smart thermostat, then you want an air conditioner that has smart technology enabled.
  • Noise. If you’re outside, the unit will be placed close to a deck or patio; you may want to consider a unit with a low decibel rating.

Choosing Your Central Air Conditioner

Now that you’ve done your due diligence and considered all the points above, you’re closer to deciding on a Central Air Conditioner.

For many people, it’s going to come down to budget. You can only buy what you can afford. Budget aside, making a bullet point list should help you choose.

Start by identifying what type of central air conditioner you want. A bare-bones, single-stage, dual-stage, or variable-speed air conditioner? Note that the choice often goes hand-in-hand with your SEER2 or energy efficiency preferences or requirements.

Your next step is to go through the list of considerations above and factor in the size of your home, your climate region, your environmental considerations, and finally, what features are important to you.

Another thing to think of is the brand or manufacturer. Some brands tend to be more budget-friendly — such as Goodman — while others, like Carrier, Trane, etc., are considered high-end.

Frequently Asked Questions

What is the lifespan of a central air conditioner?

An average of 15 to 20 years, depending on where you live. For example, if you live in the southern states and your air conditioner runs for most of the year, the continuous operation will impact its lifespan.

Should you leave your air conditioner on all day?

Yes. It’s more energy-efficient to leave your Air Conditioner running than to turn it on and off.

Do central air conditioners use a lot of electricity?

Central Air Conditioners use 1,000 watts for each ton of cooling capacity. So a 3-ton air conditioner uses 3,000 watts while in the cooling stage.

I've been helping homeowners with appliance repair since 2016. Starting out as an enthusiastic amateur, I've since worked with many Appliance, HVAC, and DIY experts over the last 7+ years. My mission is to help fix your appliances and prevent future issues - saving you stress, time, and money. Visit my author page to learn more! Read more