I'm in the high desert of Southern California. We're in a 2300 sq foot home, 2 stories with 3 bedrooms and 1 master bedroom on second story. The house is cooled by 2 central air systems, manufactured in 1990. The second story is cooled a Rheem Classic X Rahe-030jas, with the tag in the picture below. Supposedly its 208/230 Volts, 18 Amp single phase. Google says its SEER rating is 10. I'm thinking of putting Honeywell a portable mn10cesww, 10000 BTU (ASHRAE-128 Standard) / 5500 BTU (DOE+ 2017 Standard), in the master bedroom, and two bedrooms, and not running the central air at all this summer. I care only about cooling those 3 rooms. Plus I already have a small window unit in the a 4th bedroom/office, that's rarely used. The central a/c also cools the hallway and bathroom on the second story.
Will running the portables in each room at night be more efficient than running the older central air at night, especially considering that they won't be running when nobody is in the room?
Also as far as the first story goes, we never run the central air. We only cool it with a 14000 BTU portable unit.
Best Answer
My guess is that the three portables would use less electric power than the single old central unit. But the central unit is cooling and drying out the bathroom and you might have moisture problems without it blowing dry air into the bathroom.
So you want to put in three 10 kBTU/h portables, one in each bedroom, for a total of 30 kBTU/h, and you want to know if this would be more efficient that the existing old central unit which cools the second story. It is a 30 kBTU/h R-22 unit manufactured in 1990 and was rated at 10 SEER when new.
(1) What is the SEER of the portable unit? Presumably much high than 10, but you need to know what it is. The portable runs on 120 V, right? Do you know what the running current is?
(2) Is the portable a one hose or a two hose unit? If the unit is only one hose, then there would be a net pumping of air from inside to outside. This would result in air infiltration from outside to replace the air pumped out. Two hose units are better because they get the condenser cooling air from outside.
EDIT