Jack Stephenson

To the editor,

This is an information update to the Gilford selectmen and Facilities Planning Committee relative to geothermal heating/cooling: John O’Brien was helpful and gave me copies of the Water Energy Distributors report to you, which he said was the basis for your system selection and costs.

After I waded through the 75-percent snow job, some real numbers come out, such as, the investment is at least $135,000 for the well(s) system, heat pumps, and heat exchangers, and likely $2,100 per year maintenance. Even the heat distribution is far more expensive than usual efficient hot water base board heating .

The "official" plans, as available to the public, show a 150-ft. well, (Chan Eddy insists it is 1,500-ft., much more probable, since they have to go at least that deep to get water warm enough for any net gain over the electric power needed to drive it all). As an experienced graduate engineer, specializing in thermodynamics, heat transfer, aerodynamics and fluid flows, I still can’t follow how their single well can work as shown, since the down flowing COLD water will suck out all available heat from up coming water. Not a problem, since costs alone will eliminate their system.

Their report shows two 1,200-ft. wells are needed (which their data also shows is wrong, not warm enough there). They based all on lack of information and bad guesses at heating (13 times what actual history shows) and cooling needs (40 times what actual uses indicate). They assume that the whole town hall now uses 600-mbtu per year (actual from records is 333-mbtu), and that the addition will consume 453-mbtu, while calculations based on current design and indicated insulation fixes (minimum) indicates heat load of 33-mbtu. For oil heat that would cost $825 per year. Reduce construction cost by making inner-half of floor area an insulated wood floor over crawl space, and you reduce oil heat cost to $620 and get all cooling cost free, with super dehumidification. (See plans for that, previously provided. Copies available).

Currently the whole Town Hall, including police facility, is using old electric air conditioners, which costs us an average of $1,500 per year for cooling. All, or most of that cooling could come from air circulation from the basement to upper floors, solving two problems at once! No sense heating the basement when upstairs they have excess heat. That works here, why not there?

The effect of grossly overestimating heat and cooling loads is an increase in area of the ducts, size of heat pumps and heat exchangers, and space needed for the equipment. But, no matter what the heat load, the depth of the well(s) must be at least 1,500 ft, and that is the cost killer. ($70,000 plus unneeded equipment, about $135,000, enough to heat and cool for 207 years!)

For their payback calculations they assume that their system will save you $29,982 per year! They estimated that conventional oil heat and electric cooling will cost $10,000 per year, so how can they save you three times that much by charging 14 times as much, and $135,000 extra investment? So, WHO is listening?

In reality, the FPC is closing in on design improvements which will reduce heating and cooling costs to about $620 per year, and reduce construction cost.

I have a firm quote from Granite Group (our best local supplier) for required oil boiler, base board heaters and copper tubing, and pricing from McMaster Carr for all fittings, for a complete hot water base board heat system for whole police facility, which comes to $3,978 for all materials. For typical contractor cost, multiply times three = $12,000

If you do the cheaper to construct crawl space under the inner 26-ft. addition, you can get all the cooling ever needed from below it. BUT (life is full of problems & alternatives), to really efficiently distribute that cool air when needed, at least the inner 26-ft. of walls on each side should be double 2x4 stud walls spaced 9" to 16" apart, providing super insulation (R52 to R78) and space for simple, cheap cooling air ducts up to every space above. That also reduces wall construction cost for those areas by $7,750.

These are good sound engineering calculations, with costs based on what local suppliers will do. Don't come back with a rip-off contractor estimate, with no justification except a GUESS that for four times the real cost he can find a way to get rich! Go to Gilford Home Center, or even Lowe’s, to get the HIGHEST material costs and builder would have to pay.

Jack Stephenson

Gilford