Finally got the quote from the 2nd Trane dealer: Furnace: XV95 + Honeywell VisionPro IAQ, new air supply ducting to upstairs bedroom, new cold air return on main - $5865. Furnace Model No. TDH2B080A9V3VA This has an output of 49,400/76,000 BTUH for stage 1 and 2. My current 80% AFUE Heil is rated 75,000 BTUH input, so this XV95 has at least 25% more heating capacity. Heat Pump Option: XL15i - $5905 complete. Model No. 4TWX5036B1000A (3 ton capacity, house is 2300 sq ft, 2-story) Installed with Trane Coil, Model No. 4TXXCB036BC3HCA (other dealer quoted a 4TXCB036BC3HCA, so maybe the above is a typo?) ARI Ref# 1384223 Cooling Capacity, 34800 EER (cooling), 11.40 SEER (cooling), 13.5 Heating Capacity @ 47F, 37200 Region IV HSPF (heating), 8.3 Heating Capacity @17F, 24200 This doesn't exactly look like a very stellar system combination for the price as none of the specs on the HP/coil combo would qualify it for the $1500 tax credit. I do believe the XV95 would qualify however. The other problem is I don't think the furnace or the HP would qualify for our local utility rebate of $350 since you can't get the rebate on a 90%+ furnace if installed as a backup system with a HP, and I don't think the HP listed here would qualify on it's own. Guess I would have to install the furnace and coil 1st, claim the rebate, then install the HP or AC if I felt like it. It's all too damn confusing. Pricing from all the dealers is pretty close, but the quotes are not exactly apples to apples so it is a bit hard to judge. I thought the XL15i had much better efficiency ratings that listed above. Think I need a quote on an AC unit instead of the HP as I still don't like the idea of the 95% AFUE furnace just sitting there most of the time. Would love any input or suggestions.

You think you are storing heat in your attic... try sealing it up and see what happens... it will be twice as bad. You probably need more ventilation. 50% soffit vents and 50% roof vents square inches wise is needed. Your large attic space will ventilate well if there is enough. Don't depend on what your builder put in to be adequate, they usually only do the minimum required to meet code. The height of the roof will cause a good draft due to the heat rising. I've read that ridge vents aren't the best method for the roof becuase they require the hot air to turn back on itself to release. Do you have insulation covering your soffit vents. Sounds like that may be a problem. Easy to clean off with a blower from the outside.

Where is existing ductwork system located? I think your dealer is trying to sell you a new system. I think his tactics/salesmanship is more scare than factual. If you were going to have trouble, it is likely you would already have it with existing system. With that said, R-4 insulation is mighty weak. I would want minimum R8 or better especially if ductwork system is in attic. I still believe your biggest problem is being sized correctly on new system and I suggest you go back and reread your earlier thread. Negotiate with dealer on ductwork system. Material is relatively cheap and ductwork jockeys are usually on the low end of HVAC pay scale food chain. Is accessibility good? If new ductwork system, what are you willing to pay? I think that there is plenty of room in that $1800 price. IMO

The one under the roof keeps outside heat from coming in whereas the one over the insulation keeps outside cold from getting in. Does anyone have any thoughts on this theory? Anyone tried to verify it? It's radiant barrier, it doesn't keep the cold out it keeps the heat in the home OR the heat out in the summer. Heat moves from hot to cold, not cold to hot. Heat is energy, cold is the lack of energy. Energy moves around. Shades of hot or in terms of radiation moves from hot to surfaces that are less hot. (or you could say from warm to cool). The problem is: this is more complex than what the video goes in to talking about. That's inherently the problem with DIY products... most of the time they play on the ignorance of people. (This sort of thing is often times presented to me as something to sell.... but because I know better they then turn this kind of stuff into a DIY product.) Because this guy is selling a product, he's only going to tell you how great and simple it is. He wants to sell this product to as many people as possible. You have to do the prep work as I suggested earlier up in the thread... but once you do the prep work reinsulating properly, proper ventilation etc. the need for radiant barrier is greatly reduced. The reason I know this: I own a home that doesn't have any radiant barrier on it and it resides in a hot and sticky climate. Ventilation + Proper Insulation and that's really all you need. Radiant barrier can help... but without proper insulation + ventilation it probably won't make that much difference. A ridge vent by itself will not provide adequate roof ventilation; there must be eave vents to allow air to enter and rise to the ridge and escape. yep, too many people focus on getting the heat to escape and don't realize they have to replace that air that is leaving with cooler air. If the cooler air has no way in, well that hot air isn't going anywhere either... just sit in there and get hotter still. I know we'll put a roof mounted fan in there and force that heat out. LOL.