NW-Bound
Give me a museum and I'll fill it. (Picasso) Give me a forum ...
- Joined
- Jul 3, 2008
- Messages
- 35,712
I might get away with 7.5KW/9.5KW whole house generator in part because we have individual min-split HVACs for each room/area. They are so efficient. Hot water heaters are another story all together. I have two 30 gallon water heaters for two zones (for efficiency) of a small house. Each water heater uses 4.5KW. We may have to turn off both/one water heaters when using generator or ping-pong between heat and water!
I installed 2 mini-splits, a 1-1/2 ton unit for the living space downstairs, and a 3/4 ton unit for the master bedroom. Together, they keep the 1800-sqft downstairs comfortable year round. Being empty nesters, we practically abandoned the 5 rooms upstairs, and no longer use the original 5-ton HVAC.
The main reason for the mini splits was so that I could have heating/cooling with my DIY solar+storage system. They make whole-house inverters that could handle the startup requirement of the conventional AC, but such monstrosities weigh several hundred pounds, and require a battery that can supply the huge surge current. Their idle power consumption also makes you cringe.
As it turned out, the mini-splits keep the temperature much more even in the space that we actually use. We are now cooler in the summer, and warmer in the winter, while using mostly just solar juice. What's not to like?
PS. Regarding the electric water heater, I run it on 120V instead of 240V. That cuts the power usage from 4.5 kW to 1 kW to ease the demand of the inverters (I have two 120V inverters, and two 240V inverters, each capable of 2.4 kW). It takes 4.5 times as long to heat up the water using 120V, but for 2 people, the 50-gal tank can have enough storage that we never run out.
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