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How is a Manual-J Load Calculation Used to Size Air Conditioners for Homes?

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Did you know that there is only one air conditioner size that’s right for your home? Although it might seem like a bigger air conditioner would be better at cooling your home, oversized air conditioners can actually have just as many problems as undersized units. That’s why we use a Manual-J load calculation to determine the exact cooling capacity needed for your home.

What is a Manual-J load calculation?

A Manual-J load calculation is a protocol for determining the right sized air conditioner for your home. It was developed by the Air Conditioning Contractors of America (ACCA), and is the industry’s standard for properly sizing HVAC systems for homes.

What goes into a Manual-J load calculation?

Although some contractors out there will incorrectly size an air conditioner based on a home’s square footage alone, there are many more factors that go into how much cooling capacity is required for a home. When performing a Manual-J load calculation, we consider things like:

Why is a correct Manual-J load calculation so important?

An incorrectly sized air conditioner can cause all kinds of problems in your home. The most common problem St. Louis area homeowners encounter is a unit that’s oversized. If an air conditioner is too big, it will have very short cooling cycles. This leaves less time for your air conditioner to dehumidify your air, which worsens your indoor air quality. It also shortens the life of your unit because it will have to turn on and off so often (also known as short cycling).

By working with a trusted contractor who performs a Manual-J load calculation, you can be sure that the air conditioner you have installed is just the right size for your home. If you have any questions about Manual-J load calculation, or if you’d like a cooling system serviced or installed in your home, contact Jerry Kelly, your St. Louis area heating and cooling company.

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