I have a ART sytem. It was installed in the fall of 2005 by my wife and I. Design parameters are 90 and 10 degrees. I used HVAC- Calc for my heatloss-gain calculations. I have 6-600' ground loops 5' deep spaced 8' apart single pipe. I have a 2500 sq ft 2 story house plus a basement, which I don't currently heat or cool. I have two Tetco heat pumps, a 3 ton and a 2 ton feeding one duct system. Installing the ground loops was a chore. Broke the boom on a 5' ditch witch (lots of rock). Spent six weeks on a rental backhoe digging trenches (broke at least 2 dozen backhoe rock teeth). We finally got it finished the first part of November 2005.
Why did I do it myself? We built the house, did the plumbing, wiring, laid cermaic tile and hardwood floors by ourself. Paid a company to put in the original heating system, which were not happy with. Hey, we can do geo ourself. That really wasn't our plan but....There was only 1 geo installer locally and we weren't impressed. I spent a lot of time talking to Mark Ross at ART prior to deciding to do this myself. Mark was always helpful and has a wealth of knowledge.
I replaced a high efficency propane furnace (I think 100,000btu's). We only used the furnace by itself for a year. From what I remember we used 150 gallons a month of propane with the thermostat at 65. We put in a wood/coal stove after that and supplemented with the furnace when it got real cold.
Now the geo numbers. I figure we use about 1000 to 1200 kwh a month for heat. I recently put my GSHP's on a seperate electric meter so I can be sure of actual usage going forward. We leave the thermostat at 68. I live in eastern WV. Right now my EWT 43 LWT 38. entering air temp 68 exiting 88. In the fall with EWT 61 my temperature rise was 25 degrees. When it's below 30 my 3 ton runs almost constantly and below 20 the 2 ton will cycle on as needed.
Final thoughts, I would definitly do geo again, without a doubt. Would I do it all again myself! Tough call!
Cheers, Steve |