The original 1978 section of our house is cooled by a 3.5 ton Daikin heat pump. The newer 2001 section has a 1.5 ton cooling-only Trane. Both units are hooked into gas furnaces.
We keep the 1978 section cooled to 21.5 C all day and night. On a really hot day, the heat pump will generally run at 60-80% compressor speed for around 16 hours a day (these usage stats can be tracked by the thermostat). In the newer section, the little Trane only runs ~6 hours per day to maintain the same temperature. However, it's a smaller area to cool, the single-speed compressor runs at full speed whenever it's on, and, since we don't sleep there, I usually turn the thermostat up to 27 at night.
With these usage patterns, a hot July typically costs an additional $200 CAD worth of electricity (compared to December-February, when the heat pump doesn't run at all & the gas furnaces do all of the heavy lifting).
65C02 wrote on 2022-09-04, 02:59:
I like the idea of being able to roll a portable air con from my office to the bedroom as needed. Are they really that bad, even the new ones? The split systems look very nice, but so expensive!
If your two rooms are in close proximity to each other, you might want to look into a dual-head mini split. A single outdoor condenser hooks up to two blower "heads" inside; one for each room. Pricey, probably, but as others have noted, it would be a far more efficient & comfortable solution than trying to get a portable to do double duty.
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