While there are several things to consider when deciding which AC unit to buy, perhaps the most important question you may be asking yourself: What size AC unit do I need?
Not only do you want to avoid wasting money on the wrong air conditioner, but you also don’t want to throw your money out the window each month, as the unnecessarily large AC unit burns up your energy bill.
Likewise, you don’t want to buy a unit that’s too small for your house, which means it will be running all the time to try and cool you down, eventually leading you to buy a second unit.
Thankfully, you can avoid guessing games and calculate the right size AC unit your house needs.
There are several things you will need to consider, all of which will affect the size of the AC unit you will need for your house:
To come up with a ballpark, the three most important numbers you need to know:
Tonnage actually has nothing to do with weight. A ton refers to the AC unit’s capacity to cool the air, in other words, how much heat the unit can remove in one hour.
That capacity is measured in BTUs or British Thermal Units. Why BTU? A long time ago, they determined it takes 286,000 BTU to completely melt one ton of ice in a 24-hour period. HVAC experts eventually divided that number by 24 hours and came up with 12,000 BTU/1-ton AC capacity.
Using that measurement, a two-ton AC unit will remove 24,000 BTUs, while a three-ton AC unit will remove 36,000 BTUs. Therefore, the more tonnage the AC unit is rated for, the more air it can cool down.
To get a rough estimate of the tonnage you will need from your AC unit, use the following calculation:
Square footage of your home x 25 (estimated energy to cool one square foot is 25 BTU) / 12,000 –1 = AC Unit Tonnage
For example, the calculations for a 1,200-square-foot home:
(1,200 x 25) / 12,000 –1 = 1.5 Tons
You would need a 1.5 ton AC unit for your house.
If you live in a drier or hotter region, don’t subtract 1.
For example, the calculations for a 1,200-square-foot home located in New Mexico:
(1,200 x 25) / 12,000 = 2.5 Tons
You would need a 2.5 ton AC unit for your house.
This table should give you an idea of what size AC unit you need, depending on the square footage of your house (located in a temperate climate region):
|Square Footage||BTUs per hour||AC Unit Tonnage|
|450 to 550||12,000||1 Ton|
|550 to 700||14,000||1.5 Tons|
|700 to 1,000||18,000||1.5 Tons|
|1,000 to 1,200||21,000||2 Tons|
|1,200 to 1,400||23,000||2 Tons|
|1,400 to 1,500||24,000||2 Tons|
|1,500 to 2,000||30,000||2.5 Tons|
|2,000 to 2,500||34,000||3 Ton|
Of course, all the other factors we previously discussed will also affect the unit you ultimately end up purchasing:
There are commonly two different types of air conditioning systems you can install in your home: a packaged unit or a split system.
The packaged unit air conditioner is the one most commonly associated with a central air system. With this system, the evaporator, condenser, and compressor are placed in one single cabinet. This cabinet is most often located on a concrete slab outside or on the roof. This type of packaged air conditioner usually includes electric heating coils or a natural gas furnace. This removes the need for an entirely separate furnace.
This type of system is most often used in homes that already have a furnace but no air conditioner installed. It’s the most cost-effective way to install air conditioning in a house.
With a split-system central air conditioning unit, an outdoor cabinet holds the condenser and compressor. An indoor cabinet holds the evaporator. This indoor cabinet may also hold the furnace.
While it’s fairly simple to come up with a rough estimate on the right size AC unit you will need for your house, ultimately, it’s safer and will save you money in the long run, if you work with an HVAC expert to determine the proper size.
Installing central air can cost you between $3,779 and $7,429, according to HomeAdvisor.com. So you want to make sure you’re buying the right unit the first time.
Getting the right unit will ensure your cooling system can perform efficiently for years, especially with regular maintenance.
According to the Department of Energy, three-quarters of all homes in the United States have an air conditioner. Those who don’t often struggle to find relief during those hot summer months.
In this post, we’ll break down everything you need to know about central air, and how much it can cost to install in your house.
Most simply put, an air conditioning unit removes the heat and moisture from inside your home and replaces it with cooler air.
The AC unit moves the heat inside your home, outside, consists of a:
The pump, also called the compressor, moves the heat transfer fluid (refrigerant) between the evaporator and the condenser.
The refrigerant evaporates in the indoor coil, extracting the heat from inside your home, and cooling it down. The hot refrigerant is then pumped outside via the condenser.
With a central air system, the cooling compressor is located outside your home, and the fan unit is located inside the home. The system utilizes the existing heating and cooling ductwork in your home to distribute the cool (or warm) air evenly.
Many homeowners don’t realize there are two types of air conditioning systems you can install in your home: a packaged unit or a split system.
The packaged unit air conditioner is most commonly connected with a central air system. With this system, the evaporator, condenser, and compressor are placed in one single cabinet. This cabinet is usually located on a concrete slab outside or on the roof. A packaged air conditioner usually includes electric heating coils or a natural gas furnace, which removes the need for an entirely separate furnace.
If you have a furnace but no air conditioner installed, a split-system is for you, as it will likely be the most cost-effective way to install air conditioning in your house.
With a split-system central air conditioning unit, an outdoor cabinet holds the condenser and compressor. An indoor cabinet holds the evaporator, and may also hold the furnace.
It is entirely possible to install central air in an older house; it just may take additional work from the experts.
There are two main things to consider when purchasing and installing an air conditioning unit:
Determining how much cooling your home needs depends on a multitude of factors, including:
Given that older homes have a higher level of air infiltration due to gaps in molding, doorways, loose windows and doors, it will make it harder (but not impossible) to control moisture levels and humidity.
The experts at Old House Journal, an online site that helps owners of older homes to repair, restore, and update their homes, say older homes usually do best with premium air-conditioning systems with a two-stage compressor or dual compressor, and adjustable speed blowers.
Deciding to make that investment depends on the cost to install, and whether you live in a climate where you have a longer cooling season. You should also ask:
Central air conditioning units are typically more efficient than single-room units. In addition to being quiet, convenient, and unobtrusive, they can also save you energy and money in the long run.
Even if you already have a central air conditioning unit, maybe it’s time to think about an upgrade. Newer models use up to 50% less energy to produce the same amount of cool air as the older models. That means, if you installed your cooling system 10 years ago, you could save up to 40% in energy costs by switching it out for a newer model.
If you’ve decided to install central air, it is likely to cost you between $3,779 and $7,429, according to HomeAdvisor.com.
Your final bill will depend on several important factors:
While installation is relatively uncomplicated, it’s important you don’t attempt to install central air on your own. Always work with a licensed air conditioning contractor to ensure your unit is properly installed. Experts with a license are also the only ones who can handle refrigerant chemicals.
A properly installed unit can perform efficiently for years, with annual maintenance. Improperly installed units will perform just as poorly as older, more inefficient models.