Mighty Anvil asked....What kind of HVAC system? Is there perimeter eave space around the second floor perimeter? I don't know as of yet what system will be used. Probably something rather standard. And there won't be much eave space as I see it. (please see link... Our plan is a stretched version of this plan, with the bathroom moved to where the bedroom is now and the plan stretched another 12 feet to make room for the bedroom that the bathroom pushed aside.) As we have drawn the plan now, the living room goes from gable end to gable end, and we'd like to vault that one room's space. In other words, there will be two zones of attic space....one above the kitchen... and one above the new bathroom and bedroom. The vaulted living room will cut these two attic spaces from each other. Only one 8x8 bathroom AC'd on the bottom (garage) floor. However, we are considering a temporary (5years) guest bedroom downstairs. Considering a window unit for the temp room. No basement and sited on the MS gulf coast. Hot and humid. Thanks for ALL the responses... Gary and Frog... I will look at the links tomorrow. ....Spidey hearing ....!!! Here is a link that might be useful: garage apartment

I went ductless in my home and pulled all the ductwork out. I gained two closets and have a lot of storage beneath the stairs. I would look at Fujitsu's and Mitsubishi's web site and use the "find a dealer" feature. I think that because it is a bit out of your contractors comfort zone they are pushing you to what they like with the price. I spoke with a contractor who did two identical homes. One high efficiency ducted propane. The other was a Fujitsu Hybrid Flex Inverter with 1 condensing unit and 8 indoor evaporators. He said the installed cost was almost identical for both systems. The mini-splits were operating at a 50% savings over the ducted system. In new construction running small line sets is a snap. There are not as many good installers of ductless, but more and more are coming to it annually. Since '08 the only category of products that grew year over year is the mini-split category. Find the best guy and hire him. Check his references. Installing the best efficiency highest technology products in the industry won't reduce the value of your home. You will have very nearly the same efficiency as a geothermal heat pump for a fraction of the cost. One of the best features of mini-splits is their very quiet operation. mine are much quieter that the ducted system they replaced. As well, you gain efficiency by zoning the space. There are a lot of ways to save energy. One of the best is to zone the space and heat only the area you are in. My Fujitsu 15 RLS which I just installed a few months ago has a feature that will automatically set back the temperature if the unit does not sense motion in that space for 20 min. when you walk back into the space it starts up and recovers quickly. Pretty neat! I am partial to Fujitsu as I represented them in a 6 state area in my business, so bias noted.

tomylake what is your location? what size is current upstairs system? how did it perform? let me be certain I have the correct picture. current air handler is in crawl space next to basement. supply runs and one return is located in attic? room registers are in ceiling? I would not zone the upstairs. Why? probably not cost or comfort effective? I would make the return modifications. Up to you as to whether leave air handler in crawlspace or relocate to attic. You did say existing system worked fine. You would get better airflow if air handler was relocated. How large is living area in basement? I might consider zoning this area off the main floor system. If you intend to live in this home for the forseeable future, then I would drop the Payne. Either Trane XR15 or Carrier's Performance 15 would be fine as long as they are properly matched with correct air handler. Here are the matches. 3514667 Active Systems XR15 WEATHERTRON TRANE 4TWR5018E1 4TEE3F39A1 20400 13.50 16.25 18400 9.00 905172 Discontinued Systems PERFORMANCE 15 PURON HP CARRIER AIR CONDITIONING 25HPA518A30 FV4BNF002 18000 12.50 15.50 17800 8.30 according to AHRI HP Directory, the Carrier system is discontinued and does not qualify for tax credit. The Trane system above does qualify and has excellent numbers. IMO

I am trying to answer as best I can. I am not trying to be difficult, I was just not expecting having to face this major expense right after closing. The real estate market in Dallas is crazy & we were on a time limit to buy a home. Most homes have multiple offers as did ours & we had a short option period. I realize no one forced us to buy this home but I am just frustrated that 3 top rated companies are coming up with different recommendations. The system currently in place is working but if we are not going to be comfortable & it is undersized I'd rather bite the bullet now & replace before we do other work & paint before moving in. I would think that an inspector who told us he has inspected 17,000 homes in DFW would have given us a heads up that a 2 or 2 &1/2 ton mismatched system would be undersized for a close to 2,300 SF home, The ducts are located in the soffits below the attic (as was apparently done in the 60's in these homes) running in a t-shape down 2-hallways perpendicular to each other, The quotes I have received are to install all new ductwork in the attic so we can at some point knock out the existing ductwork & soffits & raise the ceiling height in the 2 hallways to that of the rest of the home. The all new duct work is approx $2,500-$3,500 of the quotes I have mentioned (although we would still have some cost even if we retrofit) . This would be done if we installed a 3, 4 or 5 ton replacement system including furnace, coil etc. I just have a hard time understanding how a 3 ton system would cool a 2,300SF home. I have attached a copy of the floor plan that the Carrier dealer created. He would not give me the load calc. We also requested an additional supply in the MBR and they will be installing a 2nd (additional) return. Thank you.