I am in the process of getting quotes for adding a horizontal ground loop, water to water geothermal heating system (no A/C) to my existing propane heated hydronic system (I would retain the propane as auxillary heat). I am in Idaho where the nearest cities are 75 - 90 miles away. The local town expert (everyone has referred me back to him and references are good) has not offered to do a heat calc. The guys from the the cities aren't offering to come out any time soon to do one. So I have used 3 online heat loss calculators to do my own (I acted as "general contractor" in building the house so I have the specs). The 3 programs are at: http://www.builditsolar.com/References/ ... atLoss.htm http://mackintosh.aud.ucla.edu/heed/download.html http://www.moorepage.net/heatloss.html All three show from 54k - 58k btu/hr design heat loss. My house is a 3500 sq ft stick frame house with straw bale infill. The rest is blown-in cellulose (roof, floor, & walls that don't have straw). I'm using a design temperature of 0 degrees F. For the 18" straw walls which also have 3 1/2" fiberglass in the framing, I'm choosing r40. I'm assuming r3.5 per inch of cellulose. The local guy has quoted $15,800 for the ClimateMaster Tranquility TMW 060 (5 ton) - excavation not included. The unit is rated at 51,000 btuh (at 104 / 32 degrees). My Questions: Is the ClimateMaster unit big enough to handle it? Are the heat loss calculators reasonably accurate? And is $15,800 a fair price? I'm getting a second quote for the identical system from another dealer. One of the city dealers said he would recommend a Hydron Module 6 ton unit. Someone else on this site mentioned the Hydron Module Combination unit as a way of getting Energy Star rating now and still doing Water to Water. Is this a good idea? Is Hydron Module on par with ClimateMaster? Thanks for your feedback. There isn't a lot of unbiased local advice I can get.