We have decided to go with geo on our whole-house renovation in the DC metro area, and are rookies to geo. Even though I've been trying to read up on this area (via this forum and other places), there are a lot of nuances and technical information that I don't understand. I'm hoping that you experts will raise my comfort level so we can make an educated decision. And unfortunately, we need to make a decision ASAP. Like another recent poster (newtogeo), I can shop for quotes, but what I'm most interested in is the following: 1. What looks to be the correct load calculation? (one quote is for 6 tons vs. another for 7 tons) 2. Should we do the zoning? 3. Does these quotes look thorough? What's missing, needs to be clarified? 4. Does the price seem reasonable (again, not asking to shop quotes, but is it reasonable for the proposed work and loop configuration)? Background information: This is for a 5,700 square foot brick home in the DC metro area. Basement is about 1,400 sq. ft. First floor is about 1,950 sq. ft. Second floor is about 1,400 sq. ft. Third floor is about 700 sq. ft. (with an additional 200 sq. ft. of attic space). New Marvin windows have been installed with the exception of a few rooms. We also are spraying foam insulation in several rooms, including under all roofs (Icynene LD-C-50). We plan to install two systems (one covering basement and first floor; second for the upper two bedroom floors). Re: the load calculations -- Installer #1 is recommending a 4 ton and a 3 ton system, ClimateMaster Tranquility 27 (originally this installer recommended two 4 ton systems). No zoning (i.e., one zone per system). Installer #2 is recommending two 3 ton systems, Water Furnance Envision. Zoning on each floor using IntelliZone and we also may sub-zone on the second and third floors. What looks like the right load calc??? 15KW auxiliary heat on both heat pumps is included. Duct work is all new. Hot water generator on both heat pumps and storage tank is included (is this the same as a desuperheater?), which will be connected to our current AO Smith NG hot water heater. Kitchen (including make-up air) and bathroom exhaust (4 full and 1 half bath) is included. Two humidifiers are included (Aprilaire by-pass, model 600 or 700). Re: the zoning -- I heard that ClimateMaster does not recommend zoning on their systems. Has anyone had problems with this? Estimate 1 which uses ClimateMaster equipment has no zoning. Estimate 2 has two zones per system (so 4 zones total). What makes sense here? We've been told that 3 wells are needed for the 7 ton total systems, and 2 wells for the 6 ton total systems. These are vertical loops and will be joined in parallel. Both heat pumps will be running off this combined loop field. (Sorry, I hope I'm using the correct technical terms here.) Based on the quotes, we're estimating that the cost difference between a 3 and 4 ton system is about $5K ($3K in well drilling, $1K in casements, $1K in equipment price). We estimate that zoning within the two systems is an additional $6-7K. Do these quotes make sense? Anything we should specifically ask about, or is concerning? Do the prices seem reasonable for the amount of work? Thanks for your advice and insight. This is a lot of money, and our dream house that we'll be living in for 20-30 years, so we want to make the right decision.