Paul: Operating a window AC unit costs more than you think
Don’t let the low initial cost of a window AC units fool you! Before you know it, the high cost you will be paying for that cool air could be more than it would be with a properly performing central unit.
Most people go to a big-box store or appliance giant and purchase $250 window units and pay tremendously high energy bills for inefficient equipment.
Some of the things I hear people say why they use window units…
Because their bedroom is just too hot.
My wife likes it very cold and the central system doesn’t get the house cold enough.
My central AC system is broke and I can’t afford the repair cost
I like the sound of the window unit and use it as “white noise.”
Some of the above reasons may seem reasonable at first; perhaps the hot room is at the far end of the duct run and doesn’t have enough airflow; the repair costs of the broken central unit maybe more than your budget and you have a strange appreciation for expensive white noise.
Most window AC units are purchased on the presumption of “what is the largest window unit can I buy for 250 bucks?” The window unit is most likely oversized for the space and waste energy. The energy efficiency rating of most window units is EER 10 and the best unit only has a EER of 11.2. This is a far cry from the minimum efficiency standards of 13 SEER for central AC systems.
Additionally, the installation of window units is poor at best. The thermal gain due to air infiltration around the unit and extra heat that enters the house through those plastic wings on both sides is pretty high. When all of the window units are on, the cost to operate the inefficient units and extra heat and moisture from poor installation is equal to the total cost of central AC system over the useful life of the window unit.
To be fair, it’s not uncommon for a home that uses only window units to use less energy than a home that has a central unit. This has a lot to do with how and when the window units are operated. If the occupants only use the window unit while in that room and the other units are off when the rooms are unoccupied then that approach can be effective at saving operating costs. However its been my experience that most folks leave all of the window units on during the day and night.
I know that its hot and muggy in the Gulf South but before you rush out and purchase a bunch of window units, take a moment and consider the cost of installing a properly designed and installed central ac system. I think that you will find that economically it’s the better decision.
For more info on how to save energy and improve comfort levels in your home or office, visit LaGrange Consulting’s website at www.lagrangeconsulting.com or call us at 985-845-2148.