As the old saying goes, bigger isn’t always better. Of course, smaller isn’t always better, either. To get maximum energy efficiency and effectiveness out of your air conditioner, you’ll need to make sure it’s properly sized, and there are a number of factors to take into account to determine the proper size before your air conditioning installation.
An air conditioner’s cooling power is measured in British Thermal Units, or BTUs. The more BTUs, the more heat your air conditioner can remove from your home per hour. Proper AC sizing means finding your home’s exact cooling load in BTU and choosing an air conditioner that’s made to match.
Pitfalls of Improper AC Sizing
Over the course of a half-century in the HVAC industry, we’ve seen a lot of oversized air conditioners. Having too much cooling power is anything but a good thing, as it will cause the AC system to constantly cycle on and off. In addition to wasting electricity, this constant air conditioning cycling leads to uncomfortable temperature changes as the system constantly overshoots your target temperature. Over time, all that turning on and shutting off can even wear out electrical connections, leading to other maintenance issues. Moreover, constant cycling inhibits moisture removal, increasing humidity levels in the home.
AC Under-sizing can be an even bigger issue than over-sizing, as your air conditioning system will struggle to keep up with your home’s needs, leading to inadequate cooling. Over time, the increased wear and tear will shorten the lifespan of your air conditioner and lead to more maintenance problems and early system replacement.
In short, it’s critically important to make sure your air conditioner sizing fits your home’s cooling load.
How to Properly Size your Air conditioning
Many homeowners incorrectly assume that their home’s square footage is the only thing that determines the cooling load. To be sure, square footage matters quite a lot; all other things being equal, a bigger home needs a bigger cooling system. All other things are never equal, though, and factors like the number of windows, the amount of sunlight that reaches the home, insulation levels in the walls and ceiling, air leaks and load-generating appliances can all increase or decrease your home’s cooling needs.
Hurley & David can help you assess your air conditioning needs by performing a home inspection. Once you’ve assessed your home’s circumstances, one of our experienced home comfort advisers will work out the calculation procedures for sizing central air conditioners as provided by the Air Conditioning Contractors of America (ACCA) and the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE). Usually, this involves a simple computer calculation based on these procedures.
A new central air conditioner is a long-term investment in your home, and you’ll need to take steps to make sure it’s a good one. Proper sizing is the first step toward efficient cooling for years to come.
Updates to the Regional HVAC Equipment Efficiency and Testing Standards
Effective January 1, 2023, the U.S. Department of Energy (DOE) will update its efficiency and testing standards for residential and commercial HVAC equipment. All regulatory changes will differ by product type and region. Since the updated standards will result in price increases across all HVAC contractors, now is the time to buy the equipment you need for your home or business.
The minimum efficiency standards for residential and commercial air conditioners and heat pumps manufactured after January 1, 2023, will increase. This change will increase production efficiency and national energy savings while decreasing national energy consumption.
Northern U.S. & Canada
All split-system air conditioners, split-system heat pumps, and packaged units manufactured after January 1, 2023, must meet the updated standards. However, split-system air conditioners, split-system heat pumps, and packaged units manufactured before January 1, 2023, can be installed indefinitely. The efficiency rating for air conditioners will increase from 13 SEER to 15 SEER in these regions.
Split-system air conditioners manufactured before January 1, 2023, can’t be installed once the updated standards take effect. All installations of products that don’t meet the new standards must be completed by December 31, 2022. However, split-system heat pumps, single-packaged air conditioners, and single-packaged heat pumps manufactured after January 1, 2023, can be installed indefinitely. The efficiency rating for air conditioners will increase from 14 SEER to 15 SEER in both the Southwest and Southeast regions.
In addition to higher minimum efficiency standards, the M1 testing procedures used for residential and 3 to 5-ton light commercial, single-phase equipment manufactured on or after January 1, 2023, will increase. This change will produce more accurate SEER, EER, and HSPF efficiency ratings. Manufacturers will be required to re-test equipment using the new M1 Standard requirements as well as publish equipment efficiency ratings using the new efficiency metrics of SEER2, EER2, and HSPF2.