HVAC 101: Load Calculation

A/C Load Calculation can be a hot topic for HVAC replacement shoppers, but unfortunately there is a lot of outdated and incorrect information floating around about how to go about it. To understand how A/C load calculation works, you must first understand how an A/C unit works.

1. How Does an A/C Unit Work?

Air conditioners do two things; cool and dehumidify. The best way for an Air conditioner to do it’s job is to cool slowly but consistently, so that it can also remove the moisture from the air properly before shutting off. Supersizing your A/C may seem like a good idea, but rapid cooling won’t give the unit time to remove moisture, leaving you with a cold but clammy home.

2. Should I Choose a Larger System to Be Safe?

A too-fast cooling cycle will also leave you with a yo-yo system that rapidly cools, shuts off, allows the temperature to creep back up and then rapidly cools again. This on-again, off-again cycle not only results in an uncomfortable environment, but will also run up your electric bill.

3. What About Online Load Calculation?

Because of the subtleties in A/C performance, true A/C load calculation involves more understanding than a simple online calculator is capable of. While square footage plays a big part in determining the size and style of A/C you need, if used alone for load calculation it will result in choosing a unit that is far too large. A professional is capable of using “Manual J” analysis and accounting for window types, window orientation, window shading, insulation of ceiling, walls and floor, air leakage, and other factors, such as the color of the roof and the number of occupants when recommending A/C solutions for your home.

If you still feel overwhelmed at the amount of options available for residential A/C, feel free to explore the rest of our HVAC 101 series. We’d also love to hear from you about any questions you may have, and can send a local comfort specialist to your home to help walk you through the replacement process. When you replace a full system with Middleton, estimates are always free! You can also find system replacement specials and coupons on our website. Call us at 1-800-404-0371 or visit our contact form today!