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Are you thinking about forking out for a new central air conditioning system?
In the US, a typical HVAC system will cost anywhere from $5,000 to $12,500. So it’s good that you’re doing your research!
Granted, that’s for both heating and air conditioning, but it should give you an idea of why it’s so important to make a wise choice. Because a bad choice will cost you even more in the long run. In money, in time, and even your comfort.
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, make sure you’ve gone through all the information below.
Rest assured, the team here at Appliance Analysts has years of HVAC experience. And while we can’t make purchase decisions for you, we can arm you with all the information you need to be able to make the best decision for yourself.
Types of Central Air Conditioners
There are two basic types of central air conditioners. They 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 this is what we’re refocusing on.
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 the unit 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, this is the most common type of residential central air conditioner in North America — assuming you live in a house.
Split systems are further broken down as follows.
Single-Stage. This type of central air conditioner has a single-stage condenser, meaning it’s either off or running at full capacity. On an energy efficiency scale, this type would rank lowest.
Dual-Stage. Moving up a step, a dual-stage air conditioner is capable of running 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.
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 in terms of efficiency, it does need to be part of a matched system. This means that 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
As you can probably guess, the packaged unit has all the components together in a single unit. The condenser, the compressor, the fan, and the blower. These units are typically installed on the roof or a concrete slab beside the foundation of a house.
They’re also often used in small commercial buildings.
Just like a split-system, these need to be attached to the 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. The larger your home and the more features you’re looking for, the more they cost. And then you have the additional costs of permit fees and labor.
Do your due diligence upfront and save yourself from a costly mistake.
With that in mind, here’s a list of everything that needs to be considered.
Size of Home
First up, you can find many “rules of thumb” detailing approximately how many BTUs you’ll need for a given space. But keep in mind that these are approximate numbers, and make sure you pay attention to the following sections as well.
To save you from looking elsewhere for some rules or guidelines, check out the following table.
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, you would use 30,000 BTUs as your baseline.
|AC Size (Tons/BTUs)||Square Footage|
|1.5 tons / 18,000 BTUs||600 to 1,000 sq ft|
|2 tons / 24,000 BTUs||1,000 to 1,500 sq ft|
|3 tons / 36,000 BTUs||1,500 to 2,000 sq ft|
|4 tons / 48,000 BTUs||2,000 to 2,500 sq ft|
|5 tons / 60,000 BTUs||2,500 to 3,300 sq ft|
Now that you have a baseline, the next thing to consider is your climate.
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’re in Canada, refer to the following table.
|Canadian Location||Climate Region|
|On the West Coast and south of the northern tip of Lake Michigan||Marine|
|South of the northern tip of Lake Michigan||Cold|
|Between the northern tip of Lake Michigan and the southern tip of Hudson Bay||Very Cold|
|North of the southern tip of Hudson Bay||Subarctic / Arctic|
The hotter your climate region, the more BTUs you’ll need above the baseline table seen above. 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. This calculation will differ by region.
But there’s more than just your climate region!
In addition to factoring in your climate region when sizing a central air conditioner, you need to consider your personal environmental factors.
Energy Star provides some excellent information in this area.
Heat gain is factored into the load calculation, which is done to determine the size of your air conditioner. There are a number of things that 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
Any of those things can either increase or decrease the necessary amount of cooling capacity. For example, 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 in hand — 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 they will do this using the Manual J calculation, an HVAC load calculation that determines the heating and cooling capacity of buildings.
There’s no law that says you can’t use this formula yourself to determine cooling capacity. However, choosing the wrong size air conditioner can be costly.
Oversized air-conditioners. Typically, an oversized air conditioner short cycle, which simply means that it powers up and down more times than it should during the day. This uses more energy and costs you more. And since you’re overworking the air conditioner, it also reduces its life expectancy.
Undersized air-conditioner. An undersized air conditioner is overworked as well. Since it has to work harder to bring your home down to your desired set temperature, it doesn’t go through a healthy series of cycling. Just like oversizing, this adds needless wear and tear to your system and reduces its 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 in 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. It stands for Seasonal Energy Efficiency Rating. And as of January 1, 2023, it 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 and this 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 your region.
|Region||Minimum Seer @ < 45,000 BTU||Minimum 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 mild 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 come with a variety of additional features. In the broad sense, none of these features are necessary and all of them will cost you more.
It’s up to individual homeowners to determine whether or not a feature is worth the price. For some, some features may be deal breakers and for others, they’re not necessary at all.
Here are some possible features you can find on central air conditioners.
Smart technology. This will enable you to communicate with your air conditioner via your 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 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 making a decision. But you want to make the right decision.
For many people, it’s going to come down to budget. You can only buy what you can afford. Putting that aside, making a bullet point list for yourself should help you choose.
Start off by identifying what type of central air conditioner you want. A bare-bones, single-stage, dual-stage, or variable-speed air conditioner? Note that this choice often goes hand-in-hand with your SEER2 or energy efficiency preferences or requirements.
With that choice in hand, 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, however, this can depend on where you live. For example, if you live in the southern states and your air conditioner is running for most of the year, that will impact the lifespan.
Should you leave your air conditioner on all day?
Yes. It’s more energy-efficient to leave it running than to turn it on and off. Leaving it on also offers better humidity control.
Do central air conditioners use a lot of electricity?
They 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.