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magellanNH t1_j7h80ee wrote

Reply to comment by pistolbristol in Heat Pumps During Recent Cold Weather by thread100

Did you notice a big capacity drop off below 0?

We had a Bosch BOVA system installed this year and are very happy with it. But as expected, it had some trouble keeping up once the temp got down to 5 or 10 degrees. (it still was putting out lots of heat but apparently not quite enough).

I had the thermostat set up to switch over to oil at 5 degrees, so I don't know how low it could have run or how much heat it could put out below zero.

Again though. This is about what I expected. The Bosch Specs say our unit goes from around 38k btus of heating at 47 degrees, to 28k at 17, down to just 23k btus at 5 degrees.

https://ashp.neep.org/#!/product/66146/7/25000///0

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pistolbristol t1_j7hahs0 wrote

The numbers quoted "feel" right for capacity. I'd say below 17F is where I start to see a noticeable drop in capacity. Anything above that and it has no issues covering the load. Fortunately, the heat pump is the upstairs zone and the downstairs is still forced hot water (oil) and a pellet stove so the coldest days I overheat the downstairs zone to makeup for the dip in capacity.

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