With springtime temperatures on the way, you’re probably thinking about how inadequately your central A/C system performed last summer. Spring is the perfect time to consider an A/C replacement.
One of the most important considerations when making your purchase is the new equipment’s size. Neither under- nor 
over-sized air conditioners are ideal, so make sure you hire a professional who knows how to properly size your new investment.
Why Sizing Is So Important
An undersized air conditioner isn’t efficient because it can’t keep up with demand on the hottest days. An undersized furnace needs to run constantly and will struggle to keep indoor temperature below 80 degrees.
Then again, an oversized air conditioner isn’t desirable either. Short cycles put additional wear and tear on your equipment, preventing your A/C from dehumidifying the air effectively and causing wide temperature swings. Larger air conditioners also have higher upfront and operating costs.
How to Size a Central A/C System
You may be familiar with online calculators that give rough sizing estimates based on limited data, such as square footage and climate. The results of these calculations are not precise, but they give you a ballpark estimate of what size your new central A/C system should be.
You can also ask a neighbor living in a similar home how well their air conditioner performed last summer. Ask how large their unit is to give you a better idea of what size equipment your home will need.
Rely on Professional Sizing Techniques
In the end, the most accurate way to size a central A/C system is with Manual J. Professional A/C contractors can perform load calculations based on your home’s size, layout, air infiltration rates, insulation levels, occupancy, sun exposure and more. Having a professional visit your home to take these measurements in person is the only proven way to ensure you invest in a properly sized air conditioner.
To learn more about choosing a new central A/C system, please contact Marsh Heating & Air Conditioning. We’ve been serving the Twin Cities metro area since 1974.
Our goal is to help educate our customers in Minneapolis-St. Paul, Minnesota about energy and home comfort issues (specific to HVAC systems). For more information about A/C systems and other HVAC topics, download our free Home Comfort Resource guide.
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