Everything HVAC122 said:thumbsup:
Also, did you add 1,200-1,500 squares to your home? I know you did not ask anything related to this, but why did you add two additional tons of air? Did the original 3 ton ever work correctly and cool the current space?
I suppose I knew there would be more questions. So here goes.
This is a four level house, including a fully finished basement. 6500 square feet. Built in 1923. Masonry walls 12 inches thick. There is an open staircase from the first floor (level 2) to the third floor. When we set out to rescue the place in 1981, there were 59 leaky windows, 50 radiators, and a 450,000 BTUH 50% efficient gas boiler. Our estimates for cooling were 15 to 17.5 tons. So we set out to tame the beast.
By 1984 we had all thermal windows and doors. Room renovations always included a new partition wall stuffed with insulation directly in front of outside walls. But we only had a couple of window ACs. In the midst of a kitichen-dining room redo, I decided we had enough of the house torn up that we were ready for central air. I believed that 3 tons would do for floors one and two, that the basement's needs were marginal, and that we could close off all the rooms on the third floor and add ductless split systems to the third floor later.
In my search for available stuff, I looked at Sears. They had some HVAC stuff at local stores. Then I checked the Sears catalog and found a treasure trove of stuff. All of the equipment, ducts, and hardware to do a complete job. Plus very helpful instructions for DIYers. So we bought a Sears furnace (105000 BTUH 96%), Sears AC (36000 BTUH, 10.5 SEER), a plenum to fit the furnace and hold the coil,a lineset, all the ductwork and parts I could think of, a Honeywell air cleaner and a thermostat. After a week of planning, it took a day to pour concrete for an outside pad, another day to mortar up cinder blocks as a base for the inside stuff, another day to put the equipment in place, wire everything up, and screw together the lineset with the components, and then we turned it on. Cooling. But no ducts. This went on until we had cooling for the first floor kitchen project, and then the master bedroom on the second floor. It was nearly a year later that we finished the kitchen renovation project and had ducts that covered all of the first and second floor, and some token air in one room of the third floor. And then on the following year, we rested.
So, this all worked well until two of my children moved to the third floor and started complaining incessantly about their degree of comfort. The ductless idea no longer appealed to me, but I had another idea--extend the return air plenum to the third floor, add return ducts to the third floor near the ceiling where most of the hot air in the house accumulated, and add some more cooling by an 8 inch duct run through the return air plenum. By this time my kids were old enough to handle tools and do heavy lifting, so they worked and I designed. We also swapped out the blower and motor in the furnace to get a lot more air flow. It all worked, but the cooling capacity was not great enough to hold a setpoint during Washington's hot spells (morning temps in the 80s, evening temps 85 to 95), and the AC runs continuously with the temp at the thermostat going from 75 to 80-85. Dry, but warm. So I think the ductwork is adequate, a one horsepower blower is adequate, but we need more cooling.
When the 20008-9 Energy Tax Credit came to my attention, I decided now is the time to buy, and I got the biggest and best stuff I could buy directly at a really good price. The difference in price between a 4 ton and 5 ton was small, and the difference between a heatpump and a regular ac was fairly small, and I am still about $300 short of spending enough to get the full tax credit (30% of expenditures up to $1500 credit).
Now I am at the point where I need professional help with the refrigeration part, and I am getting pushback from guys I have talked to in terms of price. It seems like they want to make the same amount of profit as if they has sold me the equipment, they do not trust me, and one told me I can go to jail just for purchasing the parts.
Does that provide enough background? I have a large backlog of stories about this house, some far more interesting than the one I just told.