Brevard County HVAC Experts
Technician inspecting central AC unit

What Happens If Your Central AC is Too Small for Your House?

Why Proper Central AC Sizing is Essential

One thing many newbie HVAC installers do not realize is that the size of an air conditioner really matters. When it comes to central air conditioner installation, "one size fits all" definitely does not apply, nor does the common belief that "bigger is always better."

Here's why.

Problems with an Oversized AC

If an air conditioner is too large for a particular home, it will use more power than necessary to function, costing you more on your energy bills. You may also experience uneven cooling throughout your home, where some rooms feel comfortable but others have hot spots. Since your overpowered AC will run in shorter cycles that are not long enough to draw moisture from the air, you'll also experience uncomfortable levels of indoor humidity. That same humidity may then lead to mold growth in your unit. This is because the airflow is circulating more quickly than your unit can cool and dry the air — so too much moisture is being circulated.

Problems with an Undersized AC

A central air conditioning system that is too small for your house will cause a number of problems as well. You'll still be dealing with high energy bills because your system will constantly be running since it lacks the capacity to adequately cool your home. You'll also deal with temperature inconsistencies as the system struggles to pump cool air evenly throughout a space that's too large for it. All of that effort leads to you paying more money and still not being cool enough in your home. Plus, your AC will experience fast wear and tear due to running so frequently, which will translate to more repairs and a shorter overall lifespan.

Proper AC Sizing Infographic

How To Calculate Ideal AC Size

Measure the square footage of your home that you want to cool. You might have this recorded in paperwork if you’ve recently had your house appraised. You also can estimate by walking your floor and multiplying the length by the width.

  • Multiply your total square footage by 25.
  • Take that number and divide it by 12,000, which is a number standing for British Thermal Units. (Background on this: Air conditioners are measured in the “tons” unit. A one-ton air conditioner can cool 12,000 BTUs.)
  • Now take your number and subtract 0.5.
  • So let’s say you have a 1,000-square-foot home: 1,000 X 25=25,000, 25,000/12,000=2.08, 2.08-.05=1.58.
  • So for a 1,000-square-foot home you need a 1.58-ton air conditioner.

Request a Manual-J Analysis

In the HVAC industry, the Manual-J analysis is an intensive survey of your AC system that calculates your home’s optimal heating and cooling. A professional HVAC tech can do this for you. If you want more info on Manual J- Analysis and calculation, check out the Manual J Calculator.

Weather Engineers Can Answer All Your Central AC Questions!

At Weather Engineers, we’ve been assisting Florida homeowners in Brevard County with their heating and cooling issues for many years. We’re experts in our field — and we’ll show you when we give your HVAC unit a routine checkup. We can determine if your HVAC unit is the proper size for your home and suggest solutions if it’s not. Contact us today!

Categories