Hi, Thanks very much for your responses. - Everyone I've spoken with, and you've confirmed, that one zone per floor makes sense. If I'm missing anything else about "zones", please let me know! - How much should it cost to go from 2 zones to 4? - We are definitely going to put in all new ductwork. Is there anything here that I should be aware about or ask for? Any sites (besides GW) to get more knowledge on this area so I can ensure we get the ducts sized properly? - Good comments on getting more info on the geo wells, piping, etc. Will do. - Can I get a Manual J done even if the house is under construction? Framing is almost done, but the exterior work is not complete, and so it's open to the elements right now. - Yes, we have a natural gas furnace and electric AC in the house. It appears that a NG furnace was installed in 2007. The unit is a Lennox Signature Collection, model CX34-62D-6F. We also have an electric hot water heater, AO Smith ProMax Plus, model FCG 75 300. Does it make sense to re-use these or upgrade? Obviously, the furnace will be out if we go with geo. - Here's a summary of our NG and electricity rates. I hope I'm doing this correctly -- taking the bill amount and dividing by the energy used. Some months may need to be taken out because the numbers are too high/low. Please note that we have not lived in the house, so this is what we were paying for several months before construction commenced. So I would expect actual usage, and thus our bills, to be higher, but I guess that the cost per unit would be somewhat proportional. Natural Gas Monthly Charge / Therms Used / All-In Cost Per Therm $18.06 / 5.1 / $3.54 $16.76 / 5.1 / $3.29 $51.90 / 32.5 / $1.60 $78.53 / 57.7 / $1.36 $339.62 / 314.7 / $1.08 $362.71 / 321.1 / $1.13 $184.41 / 154.8 / $1.19 $81.98 / 60.4 / $1.36 $66.62 / 47.4 / $1.41 $18.45 / 7.1 / $2.60 $16.18 / 5.1 / $3.17 $1.97 average Electricity Monthly Charge / KWH Used / All-In Cost Per KWH $285.18 / 1757 / $0.16 $137.36 / 786 / $0.17 $77.44 / 416 / $0.19 $57.91 / 316 / $0.18 $66.29 / 382 / $0.17 $86.87 / 524 / $0.17 $61.02 / 341 / $0.18 $24.50 / 76 / $0.32 $25.22 / 80 / $0.32 $38.34 / 73 / $0.53 $21.23 / 53 / $0.40 $32.62 / 140 / $0.23 $0.25 average - It must not be code on my state (MD) to have each floor zoned. Our bids have been for two zones (on per system, one system covering basement and first floor, second system covering second and third floors), or for four zones (running off two systems). - Thanks for the heads up on the tax credits. My husband is tracking these, so I'll make sure he knows this. - The addition is on a loggia, not crawl space. So the basement is a walk-out basement, and the loggia will in effect extend the basement, and then the kitchen/family room addition will be above this, and our master bedroom addition above that. It's at the back of the house. Here's an early photo so you get the idea. The house is brick, and the addition will be part brick, part clapboard. - I am trying to learn what an HRV is, so am looking into this. - If it's not a good idea to go with spray foam insulation, let me know! Thanks for the info on what type would be good. - More thoughts on what system to go with, pricing, etc.?? THANKS AGAIN!!

That's exactly how the microwave thermal switches work, I've had them fail before - Most are supposed to be self-resetting, there may be some that fail permanently. I suppose you could add a fuse or a breaker in the junction box if you're so inclined and know how to do it. I'm not sure what the advantage of flipping the motor over would be. I would assume the motor provides adequate power to the saw, and I guess a washing machine motor ought to do a reasonable job- they are fairly heavy duty, and made for a pretty long duty cycle. I can't see anybody running a saw for the equivalent amount of time.

You can't just twist the wires together and wrap the connections in electrical tape. At minimum, you need to use wirenuts or some other applicable device to hold the connection together. The new cable I have already purchased is twisted cloth covered cable - it's vintage inspired, therefore there is no ground wire You bought the wrong cable. Return it and get something with a ground wire too.

You usually can't get the stove "as close as possible to the cinderblock" anyway. Check the installation manual, but most stoves require a little bit of clearance in the back. And that's just sufficient to allow running the gas connection. This also makes sure that the stove isn't pushed back so far that the heat from the oven could damage adjacent cabinets. In most cases, after opening the oven door, the sides of the oven must still be proud of the front of the cabinets. Your installation manual will have the exact details. While you shouldn't run flex pipe through the cabinets, the connection between the valve and the stove is usually flex pipe. It allows you to pull out the stove if it ever needs to be serviced. Hard pipe would be very counter productive. For a similar reason, the shutoff valve should be easily accessible without having to remove the stove from the cabinet. That's why you'll frequently find the connection coming from the floor. In an emergency, it allows you to reach under the stove to turn off the gas. But unless prohibited by local building code, you could always place the shutoff valve somewhere else. I have seen gas pipes coming out from the floor, the back, or the sides. And they all connect to the stove using flex pipe.