First of all, I want to say thanks in advance for your replies. I as a homeowner really appreciate the free advice given here. OK, I've got a 1950's brick cottage, ~2300 sq ft downstairs and ~800 sq ft upstairs (unfinished, but will be finishing soon) with a 15 year old gas pack(sic?) unit that is starting to fail regularly. I live in eastern NC just off of I-95 for location purposes. Got a few quotes from geothermal installers over the last month. All of them ran a manual J on the house, all with somewhat different numbers. They all reported that I needed a 5 ton unit for the house. One of the installers said that we only needed 4.2 tons, but that he didn't know of a 4.5 ton unit that we could purchase. I have a bunch of numbers from their calculations, so if more information is needed to help you to help me, let me know. We like one of the installers somewhat better than the others. He has been doing Geo for >10 years now and we have some good reviews on him. Now for the questions. 1. Climatemaster Tranq 27 recommended w/ 10 year parts and labor warranty for $13355. Is that reasonable? 2. He recommended 5 200' deep boreholes for vertical loops. I have heard that you need at least 150' per ton. If we did 4 200' boreholes it would be 160' per ton. Does that seem like enough or am I just trying too hard to be a cheap bastard? He didn't have an exact quote from the well drilling company, but he put down a $15000 allowance for the 5 boreholes. Does that sound right? 3. Is a 5 ton system too much of a system if you only need 4.2 tons per his calculation? 4. Seriously, how much will this screw up my yard? 5. I do have large mature oak trees lining the road in front of my house, should I be concerned about root growth around the piping in the yard? Can't do horizontal loops cause it would kill the trees. Love em too much. Again, thanks in advance for your efforts here.