What Size Air Conditioner Do I Need for My Home?

Air Conditioner in Puyallup, WA

If you are shopping for a new air conditioner, chances are that you are looking forward to having cool air with less cost. However, it can be stressful shopping for a new unit because you don’t know what factors to consider. One of the most important factors is the air conditioner’s size. Here’s a quick guide to help you determine the right size air conditioner you need before buying your new unit.

How Air Conditioners Work

Before we discuss the air conditioner size you need, it may be helpful to understand how your unit works. When you think about your air conditioner, you likely think about the cool air coming from your vents. That cool air is a by-product of the heat transfer that occurs as your system runs.

Air conditioners need refrigerant to make the air cool. With the help of fans and condenser coils, the refrigerant in your system absorbs heat from the air and transfers it to the outside. After the transfer of heat occurs, the refrigerant moves back through the condensing coil, resulting in cool air.

The size of your unit is typically discussed in BTUs, or British thermal units. This is the amount of heat it takes to raise 1 pound of water by 1 degree Fahrenheit. You may also see air conditioners rated in terms of tons. That is simply another way to express BTUs, with 1 ton equaling 12,000 BTUs.

The BTU rating is a representation of how much heat the system can transfer every hour. The more BTUs, the more capacity it has for transferring heat out of your home.

Bigger Should Be Better, Right?

It would make sense that more BTUs would cool your home better. However, that is only conceptually true. Not only does your HVAC system have to circulate refrigerant to cool your home, but it also must circulate the air from within your home.

Your air handler, which is often part of the furnace unit, has a limit on the volume of air it can circulate. A mismatch between airflow and heat transfer capacity will cause the system to freeze because it isn’t absorbing enough heat.

An air conditioner also works to dehumidify your air. If the cooling and airflow capacity of the unit exceeds your home size, the unit will not run optimally and efficiently.

This leaves you paying more for your larger air conditioner and more to operate it. Rather than getting a large unit that costs more in the long run, work to find the right size for your home. The following steps will help you determine the correct size of air conditioner your space needs.

Determine Your Service Space

The very first step is to determine the size of your serviceable space. If you have documentation from when you bought your home, you may start with that.

However, that square footage only accounts for livable space. Your AC may also service non-livable spaces, such as your basement, garage, or attic. Look in those spaces to see if there are HVAC vents, and include those areas too.

Determine How Many BTUs You Need

Next, multiply your serviceable area by 20, for 20 BTUs per square foot. This is a rule of thumb estimate used across the industry. If your home is 1,100 square feet, you should be looking at a 22,000 BTU unit as the starting point.

Variables Play a Role

This initial estimate assumes several variables that may need adjusting based on your home. The calculation accounts for two occupants. Add 600 BTUs for every additional person who is in your home while your AC is running.

Next, consider the amount of shade or sun your home receives. If you have no shade, you may want to increase your estimate by about 10%. However, heavily shaded homes can reduce it by about the same amount.

You should also consider how many windows you have, whether you have tall ceilings, and if your home is in the shade or sun. An air conditioning specialist will help you consider all the variables affecting your unit’s performance.

Make Sure It Will Fit

As already mentioned, you want to make sure your cooling capacity will match your airflow capabilities. Before you order your new unit, the specialist you’re working with should consider your air handler as well as your ductwork. This will ensure that the new unit will accommodate your home perfectly.

People around Puyallup have turned to Puyallup Heating & Air Conditioning for dependable air conditioning service for over 70 years. Our team proudly offers expert heating and cooling installation, maintenance, and repair. Call to schedule a consultation with one of our experienced technicians today.

Tags: