Rockytopper,
I went with the closed loop for several reasons.
1) I don't want to pump silt or fish into the system.
2) I don't want to take care of a filter
3) It uses a much smaller pump than an open loop would require
4) My HVAC man told me to.
The unit is no bigger than a standard furnace, and there is no outside unit at all. The supply and return tubes are about 1 1/4" and run from the indoor unit to the pond. Again, there is a 3000' loop on a 8'x14' frame in the pond. The 3000' loop is actually six 500' loops in parallel. My tubes go from the unit, up and across the basement ceiling to the other end of the house, out the wall and down the side of the house, and underground to the pond.
The red tubes carry domestic water through the "superdeheater". Yep, that's right. A superdeheater. It catches the heat that would otherwise be wasted, and circulates it through my water heater. It makes enough hot water for my whole family of four. I have my two 80 gallon water heater circuit breakers turned off, and we have plenty of hot water. 160 gallons of it to be exact. The heat is taken from the hot side of the compressor. I have radiant heat in my kitchen and master bath floors. This winter, I am counting on this superdeheater to warm these floors.
Sorry for the quality of the pictures. The two white things are the loop pumps. One pushes and one pulls. They are about the size of your fist.
Since I don't know what my power bill will be yet, I have to say the thing that impresses me the most about it so far is that it can cool this 4100 sq.ft., half of which has 20' ceilings, so well. It acts like it is bigger than 6 tons. The blower in it uses a DC motor with 12 speeds. It ramps the speed up and down depending on how many and which zones are calling for cool. Pretty neat.
I would tell anyone that asks, if you are going to stay in your house for a while, and you can spring for the initial cost, then get a WaterFurnace. I figured to break even on it in 5 years, but I didn't even count the free hot water. It is a very well built machine.
