Holliston LEED House

This is the story of a family who built the first LEED "green" house in Holliston, Massachusetts. We were trying to spend no more than it would take to build an ordinary house,and maybe even succeeded. The dust is still settling.

Friday, October 17, 2008

Closed loop, open loop…

The cost of geothermal varies greatly depending upon whether you plan to plumb your house for radiant heat or use a simple air system with ducts. The way we’re leaning now is to build an open loop, one hole geothermal system (which you can only do if your water quality is Fabulous) which works by digging our water well deeper (to 500 feet). Then, the system drains at the bottom of the hole, while our drinking water is supplied from a depth of 140 feet and ne’er the twain shall meet, I hope.

Using one of the two name brands (ClimateMaster or Water Furnace), we then limit our cost for the geothermal to the well (ours is costing around 8500k including water well for 5000 which we had to get anyway), plus a backup dry well (leaching field), and the interior machinery and ductwork, which goes for about $5000-5500 per ton. In our two story, cathedral ceilinged 2800 sq ft house, we need to move 5 tons of air.

Generally speaking, a standard forced hot air heating system here costs about 15,000. This means the geothermal is roughly double that. However, you won’t be buying fuel every year, so up here in New England that means it pays back at around 2000 a year, net of the increased electric.

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