Homes That Perform!

Home Air Conditioning: The Problem With Oversizing Part #1.

Posted by Michael Kamps on Fri, May 17, 2013 @ 02:16 PM

Air Conditioning Oversizing Causes and Effects Part #1

Customers depend on the expertise of contractors in selecting air conditioners. Yet contractors generally size air conditioners at least a half-ton larger than necessary and oftenSizedTooBig oversize by a ton or more. Even the most conscientious contractor is driven to avoid call-backs (or even lawsuits). An oversized air conditioner can mask problems from duct leaks, improper flow across the coils, and improper charge.

Unfortunately, many customers think that "bigger is better,"

Too often many contractors will say, "I've done it this way for 30 years and I've never had a complaint." It is no surprise then that air conditioners are oversized; however, the advantages of a properly sized air conditioner are so large that these barriers need to be overcome. Customers pay a price for oversized air conditioners, and in many climates, lose comfort as well. A properly sized air conditioner costs the customer less.

Here are the problems of not sizing the system correctly:

#1 Short cycling. One of the easiest symptoms to recognize is short cycling of the central air conditioner. If the unit is turning on and off four to five times per hour in the heat of summer, it’s not operating efficiently. Instead, the unit should run continuously for 40 to 50 minutes out of every hour to maintain consistent room temperatures and achieve more comfortable humidity levels. Building Science Experts will tell you, “most homeowners don’t realize that when the AC unit first turns on, it goes through a startup process that will use more energy in the first 3 minutes than it will use in 30 minutes; and if a unit short cycles four times an hour, it’s using as much energy as it would running two hours continuously.”

Little Known Fact: It Takes More Energy To Start-Up Than Run Continuously For 30 Minutes! Most homeowners think it's a good thing if your HVAC system runs less. That's wrong.

If You're Not Sure About Your System, We Recommend An A/C Tune Up:

Air Conditioning Repair or Tune Up

Tags: Installation, Proper Sizing, Planned Right, Comfort