Few Important Things to Know When Determining the Size of an AC

The size of the AC is one of the most important criteria while buying an AC. That’s because if the AC is undersized, it will not offer the required cooling and will also wear out quickly because of overload.

Similarly, if the AC is oversized, it will not only be more costly but will also consume more energy, leading to hefty energy bills. It is, therefore, essential to determine the correct size of the AC before you call up an expert for AC replacement in Poway, CA, or nearby areas.

First Things First – AC Ratings

All HVACs are rated in terms of their cooling capacity and energy efficiency. While the cooling capacity is measured in BTUh and BTU, the energy efficiency of an HVAC is represented in terms of SEER.

SEER (Seasonal Energy Efficiency Ratio)

SEER, also known as Seasonal Energy Efficiency Ratio, tells us about the energy efficiency of an HVAC. It is the total amount of cooling divided by the total electrical energy used during an entire season. The higher the SEER rating, the more energy efficient the air conditioner is.

BTU and BTUh Ratings

The cooling capacity of an air conditioner is represented in terms of BTU and BTUh. All ACs will have either of the two. While BTU, or British Thermal Unit, is the amount of energy required to increase the temperature of a pound of water by one degree Fahrenheit, BTUh is the amount of cooling an air conditioner provides in an hour, also known as ‘tons.’ A one-ton AC removes 12000 BTUs of heat per hour.

Factors to Consider When Determining AC Size

Here are some important factors that one must consider when determining AC size.

The Size (Or Square Footage) of Your Home

This is the most critical factor when determining the AC size. When calculating the square footage of your home, omit the areas that do not require cooling. For instance, you might not require cooling in spaces such as your basement and garage.

The Height of the Ceiling

Usually, the ceiling height of a standard room is around 9 feet. But some homes may have rooms with higher ceilings. The Higher the ceiling, the more volume, and the bigger the size of AC you would require.


A home’s insulation plays an important role when determining the size of an AC. The higher the insulation, the less energy required to cool a space. This means you need a smaller AC to cool a well-ventilated room.

Other Factors

Besides the above-mentioned factors, you must also consider other factors such as the number of windows, whether the windows are single-pane or double-pane, the number of occupants living in the house, and the climate the house is exposed to.

If you are looking for a company for air conditioner repair in Riverside, CA, or surrounding areas, then we at Airight Cooling Heating & Plumbing Inc. would be happy to help. We are one of the most trusted names for AC service in Riverside, CA, and nearby areas.

To schedule an appointment, call us at (866) 247-2420 or send us an email at [email protected], and one of our team members will get back to you.