Our HVAC system has been limping along for about 6 years now and we've replaced nearly every major component except the compressor during that time (including the control board, squirrel cage, condenser, at least two capacitors, and motor). We had our biannual checkup the other day and they said the system was down 3 lbs (although we have no complaints with the way its cooling). At $130+ per pound, we declined to have the system recharged and are looking at replacing the whole unit. It's 15 years old and is a combination A.C/gas pack unit). And apparently it's using R12 which is going away (or has gone away). As we start to get quotes, are there key questions we should be asking the A.C. people concerning replacement of the unit? From talking with one company, a "Manual J-load calculation" is required in North Carolina and permits are required to be pulled as well. This is the first time we've had to replace an A.C. unit, so all suggestions are welcome (including which brand is most reliable). Thanks, Andy

Not sure if this belongs here, but it's a propane related question. Back in December of last year, I bought a house with a buried 1,000 gallon propane tank. It didn't take long to realize that it's a REALLY expensive way to heat a house. I took on the cost of bringing natural gas to the house, which has about a 2-year payback according to my calculations. I left only the hot water heater hooked up to the propane tank - everything else is now NG. The rationale is this: 1) the HW heater was the only appliance that could not be converted to NG, 2) the HW heater is a 75-gallon, power vent unit that will cost $1,500 to replace, 3) I have 800 gallons of propane to burn. Knowing that the HW heater has a 72,000 BTU burner, I figure I'll run out of propane early next year. At which point I'll bite the bullet and put a NG HW heater in. The plumber that did the NG conversion left me a plugged "T" near the HW heater so I can easily swing over to NG. So the question is, when that HW heater does run out of propane can I hook up a BBQ grill tank to it where it connects at the 1,000 gallon tank to get me through the transition to NG? I figure a 20 lb. cylinder would last about a week. There are 2 regulators - one at the tank and another before the plumbing goes into the house. The fitting from the tank to the first regulator looks like it will go right into a 20 lb. tank.