Hansberger Refrigeration Blog: Your AC Repair Resource

Sizing Considerations When Buying a New Air Conditioner

It’s tempting to rely solely on the energy-efficiency rating of a new air conditioner to get an idea of it’s energy consumption, but this rating is just part of the story. Air conditioner sizing also plays an essential role in keeping energy consumption low without sacrificing comfort.

It seems counterintuitive that bigger isn’t better when it comes to a new cooling system. In fact, a system that’s too large will drive up your energy costs and leave you less comfortable. One that’s too small won’t be able to handle the hottest weather we experience.

When you replace your air conditioner, make sure that the HVAC pro you work with conducts a Manual J calculation for your home. Manual J is computer software that determines how large your new central HVAC system needs to be to efficiently and comfortably condition your home. In other words, air conditioner sizing is crucial. The Manual J calculation measures the structure’s characteristics, which include its:

  • Insulation levels in attic and walls
  • Cubic footage
  • Number and size of windows, as well as their energy efficiency and placement
  • Home’s orientation to the sun
  • Style of home
  • Number of stories
  • Rate of air infiltration
  • Preferred indoor temperatures and age of residents
  • Landscaping factors

After the HVAC pro inputs all the information, the software returns a suggestion about the tonnage. Although this air conditioner sizing process is involved, it’s well worth it for the following reasons:

  • A system that’s too large will run in short cycles, which drive up your energy bills. Your home will cool before the equipment has a chance to enter its most efficient operating stage.
  • Air conditioners and heat pumps use the most energy when they first start. Shorter running cycles that are more frequent throughout the cooling season are hard on the unit’s parts. You may see increased breakdowns, as well.
  • These short cycles also leave behind dust and humidity, since their running time is short. Humidity makes you feel warmer and contributes to mold growth. A higher particulate load can trigger airborne allergies.
  • You’ll experience reduced comfort in rooms that are further from the air handler.

If you’d like more information about air conditioner sizing, contact the pros at Hansberger Refrigeration and Electric Company. We provide HVAC services for Yuma-area homeowners.