Hi Ned
the el. power consumption is always cheaper when you use the heatpump.
In Germany al ot of people have their own solar power plants with overcapacity in summer.
They use partly the heating element, because it works without wear and spare lifetime of the compressor. and the homemade el. power is for free.
When making hot water with the heat pump you should start the boiler schedule at a time of the day when you usally expect the highest outside air temperature. eg. In Germany after 1 p.m.
If the capacity of your boiler big enough it would be o.k. to enable the hot water only from 1 p.m. to 4 p.m.
