>>> Our AC died two days ago. I am replacing the AC unit this weekend. I have 3.5 TON unit. The best quote I got is $2200 for new 3.5 TON unit (converting to 410a), new coil, new pipes (from teh coil to the unit), some duct work, 5 years warranty on the unit and 2 on labor.... Mick: Where do you live? $2200 for a 3.5t unit is a decent price for a low-end system. What brand and model # did they quote? It's hard to compare prices unless you are positive it is apples-apples and then even regional pricing are different (don't ask me how that's fair). Tarek: The quote above for ~$2400 is around what I was getting quoted this year to replace the coil in my 2.5t gas/electric packaged unit located on the roof. Replacement units ran anywhere from mid $3k to $10k for approximately the same level systems (Ranging from 3-3.5ton, 13-15seer, and 45-70k btuh on heating input). The Home Warranty can sometimes screw over the homeowner, other times not as bad. Sometimes the contractors are held (read: encouraged) to keep costs very low to keep business coming their way. So they are paid pennies for the covered part of the installation and they must recoup the cost somewhere. So it comes out in higher non-covered charges for installation.

Q1. any length of any pipe, touching or embedded in the mass which is a heat sink for a time before it becomes a heat source. Q2. thermal mass is a flywheel. Takes more energy to get started, then provides even energy for cooking. Also extends available cooking time a bit longer, once the sun rays get weaker at the end of the day. No way to raise heat except with more sun. Holds heat and evens out heat peaks and valleys if sun rays get blocked by trees or dense clouds for an hour or two. Good for certain kinds of cooking. Q3. to concentrate the heat, design your thermal mass to be like two bowls facing each other. Insulate the outside of all the mass. Flex tubing allows you a range of motion (upper bowl, deep and high). For high-tech effect, bottom bowl (shallow pan) can be held up with three rigid fiberglas tubes filled with foam; fiberglas being the solid that conducts the least heat. Q4. The advantage over solar powered Reflectors Made of Thin Metal is ... ? cooking different types of food? Foods that require hours of simmering? (soaked beans, etc) . Know recipes, nutrition, foodstuffs available, needs of local population, etc. Q5. One advantage might be to offer a fluid-and-tubing kit that one can add onto a stripped down solar reflector (bowl-shape), to turn it into a stored heat cooker after adding sod as thermal mass. Insulation layer can be local material too. So it can work in stripped down, or in fully dressed mode. HTH ! david

Twee I would get a second opinion. Leaks at a valve are usually easy and relatively inexpensive to repair. Evap coil leaks In an air handler can be another matter entirely. Standard procedure when adding refrigerant is to include dye especially when tech did not attempt to find the leak. Let the system then run for several days and return to check coil to locate leak with proper tools. Was dye inserted? Do you even know? Yes, evap coils can be replaced in an air handler. However, usually this s not cost effective due to the expense. I assume air handler is out of warranty. IMO

I am not optomistic about utilizing new coils at latter date that are installed now. At best it limits your options for replacement heat pumps. I lean toward "wait and see" because you hadn't noticed any change in performance.