Thanks for your help, zL700; I like your link for SlimDuct enclosure, much better than my idea for 3"-4" pvc pipe! I plead guilty to a LOT of sharing! Once one reads all the way to the end, my question in the first line was 'history' : "Can anyone support my argument that it is ample to use a dual split unit for just the front two bedroom's? " This would save both cost and a difficult condenser install location. In short: We have a MrSlim MSZ-A17NA single-split 17 Kbtu unit for the 3rd floor finished attic, and a conventional 28 Kbtu ducted unit on the first floor. Our calculated 50 degree day heat loss for the entire house is 48 Kbtu, of which the two rear small bedrooms are only 5 Kbtu each. I have agreed to put in a dual-split 9+9 or 12+12 for the two 2nd floor front bedrooms. Shouldn't this effectively cool the entire 2nd floor? I need technical, experienced opinion to support my desire to avoid having to put in a 3rd condenser in the larger of the two rear bedrooms. Thanks to All - - Old Salt Details were dated SEP 3, 2307 hours.

"Cast iron steam radiators under windows are rare in all but the smallest of rooms..." What? I grew up in a town where many of the houses were heated with steam, including my house. IIRC 17 steam radiators, added well AFTER the house was built, and every one of them was located under the windows. The same was the case in the homes of my friends. The house my Mother lives in right now was originally built with gravity hot air, but around 1912 was converted to gravity hot water. All of the radiators are located under the windows. Steam radiators don't solely rely on height to delivery heat. Just as with hot water radiators, steam radiators can be made shorter and longer to increase the radiation surface. The radiator under the bank of windows in the dining room was 24 sections, height was about 30 inches. I'll stick by my original assessment -- unless the owner is willing to put a rather massive amount of money into an old home -- totally new systems, insulation, windows -- a simple switch from steam to forced air doesn't make much sense. That may, or may well not, be appropriate, feasible, and possible. I'm certain, though, that if you do have 40 years of experience in this that you'd know there's often a point of no return where spending money to make upgrades is not only a waste of money, it's foolish.

Air conditioning sometimes will work randomly like you describe, doesn't fail all at once. What you describe could be a number of things that it's best if you hire a pro. Thermostats are nothing more than elaborate switches that turn the system on / off. While thermostats do fail, typically it's because the unit will not come on at all. Your air conditioner (when operating normally) takes heat from inside and dumps it outside. When something inhibits that operation of heat removal, you don't get any cool? (cool is a by product of removing heat) Most of the time this involves the compressor, refrigerant charge and in some cases much more than these two things. (everything has a purpose for proper operation) I service the Katy, Texas area.

We closed on our house before it was finished. It was finished enough to get CO. It was a custom build, we owned the land and we trusted our builder to complete everything after we closed. The things not finished were the kitchen which was missing some cabinet and drawer fronts, molding along top of cabinets and cabinet hardware. The porches also needed to be screened in. With a tract builder I am thinking they will not allow it.