Quote:
Originally Posted by AC_Hacker
How well do you know the heating requirements for your house?
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Last January we used 95 therms according to the gas company. This is split between the 15 year old gas furnace and our very nice tankless water heater. 95 therms in January works out to be a bit over 12,000BTU/hr. This January was a bit warmer, but I've also dumped some extra insulation in the attic and sealed up some obvious leaks around doors and windows so we used 70 therms.
For the summer, my plan is to get something on the order of 200' of pipe under 10' of depth (where ground temp doesn't vary as much). 5X40' holes will give me exactly that and 50' sounds marginally doable from looking at well reports in the area, though this could quickly change. Once I get this pipe in, I want to setup a heat pump in a cooling config and just shove the air->refrig evap in our existing duct work so I can use the existing furnace blower to pump some cool air through the house. We currently have nothing in the way of AC so any cool air in the house for those 10 days Portland gets hot will be an improvement.
For the winter, we already have a tankless water heater that puts out far upwards of 12,000BTU/hr (don't have the exact #'s on me but its on the order of 2-4 tons I believe) and my goal is to setup a water-water heatpump as a pre-heater for the tankless. If I can get a continuous flow of 90F from the heatpump, the tankless can easily crank that up to 140F and run that through a radiant floor. And the furnace will still be functional in the event we need something to fall back on.