When it comes to air conditioners, bigger isn’t always better. And neither is smaller. The right size matters more than most homeowners realize. According to ENERGY STAR, an improperly sized or installed air conditioning unit can lose up to 30 percent of its efficiency before it ever runs a full season. That means higher bills, more wear on the equipment, and a home that never quite feels right.
What Happens When the AC Is Too Big
An oversized unit cools the air quickly and often so quickly that it shuts off before completing a full cycle. This is called short cycling, and it creates a handful of problems. The system never runs long enough to pull humidity out of the air, so the house feels hot and humid even when the temperature reads correctly. The constant starting and stopping also puts extra strain on the compressor, which is one of the most expensive components to replace. Over time, an oversized system wears out faster and costs more to run than a properly sized one.
What Happens When the AC Is Too Small
An undersized unit has the opposite problem. On a super-hot day, the AC runs constantly, working as hard as it can without ever catching up. Your energy bills go up, the system never gets a break, and certain rooms, especially those farther from the unit, stay warmer than the rest of the house. Like an oversized system, one that’s too small also wears out faster because it’s always operating at full capacity.
How the Right Size Gets Determined
Sizing an AC unit correctly isn’t something a technician does by walking through your house and making a rough guess. It involves a load calculation, which takes into account your home’s square footage, ceiling height, insulation levels, window size and placement, local climate, and the number of people who live there. Our post on HVAC system installation walks through some of the other factors that go into a proper setup.
Square footage alone won’t get you to the right answer. A well-insulated newer home with small windows needs less cooling capacity than an older home of the same size with poor insulation and lots of south-facing glass. Climate matters too. Ozark summers are hot and humid, which affects how hard your system has to work to keep up.
What to Watch Out For
If a contractor gives you a quote without measuring your home or asking questions about insulation and windows, that’s worth noting. Many systems get oversized simply because a contractor rounds up to be safe, or because a rule of thumb gets applied without accounting for your home’s specific details. The result is a system that costs more upfront and underperforms.
Before signing anything, it’s worth doing a little homework. Our post on 6 questions to ask before an AC install gives you a solid starting point for the conversation.
If you’re thinking about a new system and want to make sure you get the sizing right, give us a call. We’ll take a proper look at your home and give you an honest recommendation.