As we’ve touched on in the past, the HVAC system has become a problem source for home efficiency, and oversized HVAC equipment is a problem with consequences that, perhaps, are not being adequately communicated.
Here are five reasons why oversized HVAC equipment is no good:
1. Dollars & Cents
Oversized HVAC equipment has a higher initial cost and costs more to operate. That’s because the system runs in short bursts, which is about as inefficient as the rush hour stop-and-go routine is on your car’s fuel mileage. Longer run times reduce cycle losses and bolster efficiency.
It’s also just plain hard on your stuff. An oversized compressor is destined for a short life.
Oversized equipment causes temperature swings. Shorter cycles leave your system playing catch-up—particularly along the perimeter of your home—because, by the time your thermostat feels the change in temperature, the temperature has dropped or risen several degrees in the more remote areas of the home.
The greater the oversize ratio, the bigger and more maddening the temperature swings.
An oversized system is noisy. Whether you’re working from home, doing some reading, or just trying to hear your mumbling teenager, constant background noise from your HVAC system is annoying.
4. Indoor Air Quality
Again, oversized systems equal shorter run times—which, in case you hadn’t noticed, is a problem on a number of levels. Not the least of which is a lack of air filtration.
Oversized units may result in dust mites, mildew and/or mold.
Nobody likes the word “moist.” That’s science. Nobody likes excess moisture inside of their home—or out, for that matter. But, um, in case you hadn’t heard, oversized systems have shorter run times, and that means moisture.
That’s because it takes about 10 minutes for the coil to reach a low enough temperature to actually condense water vapor. And since the system is constantly stopping and starting, the thing is spending way too much time operating in the dry coil phase.
And, yet, in spite of all of this, oversized systems persist despite the overwhelming rationale to knock it off.
So, how do you figure out what size system works best for your home? Head on over to Load Calculations 101 to learn about load calculations and how they play a role in determining the right-sized system for a home.