When it concerns your air conditioner. Believe it or not but most a.c contractors don’t know how or don’t bother to properly size your air conditioning unit. Most of them (contractors) oversize. A unit that is somewhat smaller actually does better bye reducing the cycling times. There are three reasons why sizing is important, 1; cycling times, 2; moist control, and 3; noisy operations. We’ll start with short cycling first.
Short cycling refers to the time it takes for your a.c to start, reach the desired temperature, and shutoff. An airconditioner normally reaches peek performance within ten to fifteen minutes and will continue to run without the extra draw of power it takes to startup, if it didn’t that extra voltage needed would fry your system. Now, with a system that is oversized reaching the desired temperature is quicker thereby shutting down the a.c shortly after reaching peak performance, you would save on your electric bill by letting it run longer rather than having it continually draw the extra power for starting up. Wich leads us to moisture control.
It takes time for the air conditioning unit to replace the warmer air with cooler air. As the air is flowing out of the vents it is drawing air into the return, and forcing it back outside. The return air blower motor is pretty powerful, it is drawing air from not only in the rooms but from the walls, attic, and crawlspace if the insulation is inadequate. So if your a.c is shortcycling it doesn’t have the time to remove the humid, stail air making the occupants uncomfortable.
Noisy operations; A unit that is oversized and forcing air out of vents and into the return (a large unit has more air flow and higher air speed) reducing the filters effectiveness if the return air grille is to small, the size of ducts should correspond with the units size.
The positives of having a properly sized a.c; smaller units are cheaper (relatively speaking), smaller utility bill…which can help pay for the unit over time, and air quality that will be be compfortable for everyone…which is important for infants and the elderly…but that is another post, maybe next week’s
Make sure your contractor does a “manual j” to properly size the unit and ask what method was used to figure it out. A qualified computer method from RHVAC from elite software has proven to be pretty reliable, and there based out of Bryan, TX , so there still somewhat local and deal with our humidity. You can contact them at 800-648-9523.
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