janarvae, thanks for the very thoughtful response. Getting a response like yours was what I had hoped for. Unfortunately, I got some responses from "professionals" who could not or would not put their bias in check and looked upon my initial post as an attack on their careers. As an airline pilot out on disability, I know well about attacks on one's profession, "How many drinks have you had today?")
You express to me that you may have been a bit dismayed by some of the bids, but that you really enjoyed the challenge of doing the job yourself. I can relate to that. If I lived in the house in Florida and had all of my tools there, I might have tackled the job but I was just trying to verify that the bid I got was fair. Because of the well thought out responses I got here, I have come to the conclusion that it is a fair bid and I already had a very substantial reference for the contractor. Guess I was just trying to verify that. Thanks again.
PS, would love to have a doctor like you where we could do "garage talk". Lou
Sorry for the drawn out post earlier, I just wanted you to hear the opinion of a fellow South Florida homeowner who was in your position and chose a different route.
Back to the pricing, I removed my old 4 ton condenser + air handler myself and placed the new 4 ton condenser in place of the old and brought the air handler inside. Mind you that the condensing units at my home sit on a 6 foot (yes, feet) tall concrete pad due to flooding (live on an island). I paid $1500 CASH for them to braze the lines (didn't even flush or flow nitrogen while brazing), take out the air handler fan and coil to lift it into the attic space (they weigh about 150-250 lbs when full and I can lift them myself with some effort), reinstall coil + blower, braze lines and then open base valves to allow refrigerant into the lines (they didn't even add charge as they were supposed to due to the length of the lineset being more than 15 ft and didn't even install the included TXV valve!!!!). Two "techs" came and took less than 7 hrs (I was home the whole time and even gave them lunch) and one tech said it was his first day working on anything HVAC. My quotes with buying the system from the HVAC company were coming in at 7-8K for a STRAIGHT COOL (not heat pump) with re-using the old lineset and add 1K for heat pump.
There is a great debate as to whether or not you can re-use the old lineset (copper tubing) by simply flushing with ONLY nitrogen OR nitrogen + R-11. When you have them install, be sure they do the following or they aren't worth their salt.
-Recover the freon left in the old R-22 system with a recovery machine (it is illegal to vent refrigerant into the atmosphere, only a small quantity/De minimis is allowed when installing/removing gauges (they should be using low-loss fittings if they're smart), releasing mixtures of refrigerant with nitrogen for leak testing, etc.). If the old system leaked out all the refrigerant, this doesn't apply.
-Burst nitrogen to clear lineset before first braze, then flow at a low rate while brazing, while leaving one end open to the atmosphere so you don't end up with pressure in your lines which would cause pinholes in your brazed joints
-Remove schrader valve cores (identical to tire air valves) while brazing the liquid and suction lines to the condensing unit or else they risk melting the o-ring on the schrader valves and causing future leaks
-Not installing a TXV (improves efficiency) and using subcool + lineset calculation from manufacturer to determine how much refrigerant should be added/subtracted to the freon that already comes in the condensing (outside) unit or adjust TXV
-Making sure they use wet rags to cover the TXV (if a sweat-in/brazed connections vs screw-on connect because you install the TXV after brazing so it doesn't get damaged by the heat from your oxy-acetylene or turbo-torch) and the base valves outside to prevent damage
-They should braze then leak test/soapy bubble test with nitrogen to 50-150 psi (higher may damage system components, see manufacturer recommendation)
-Then triple evacuate the system using a MICRON GAUGE!!! I cannot stress the micron gauge enough, it should vacuum (negative pressure) down to 500 microns or less and be able to stay below 1000 microns once you turn off the vacuum pump. If they don't use a micron gauge they are most likely hacks (if they don't pressure test with nitrogen either)!!
-Triple evacuation is vacuuming down the system, then pushing in 2 psi of dry nitrogen to dry and water left in the lines for 1 hr, then vacuum again, add nitrogen, wait, then final evacuation down to 500 microns or below
-Adjust TXV or add/remove refrigerant as needed to obtain proper subcool and superheat calculations.
-Have no kinks in the flex ducting as this will cause air flow restriction (BAD)
-Use mastic with or without fiberglass mesh to reinforce joints. There is also debate over mastic vs good metal tape vs clear silicone.
-Insulate the suction line (bigger copper line) along its entire length.
-If installed in an attic or above any place that can be damaged by a backed up drain/condensation line, they should use a overflow sensor + a drain pain and maybe even a secondary drain line.
-They should pull a permit for the job and then it should be inspected.
The list goes on and on, but if they do most of the stuff listed above, they will probably do a good job overall.
Oh, and most places around here only offer a 1 year labor warranty with installation. I hope he makes the plenums out of sheet metal vs duct board (fiberglass covered by silvery sheets on both sides) or plywood. Sheet metal is really the Cadillac of HVAC materials. Duct-board is cheap and quick and there is also debate about the fiberglass inside of it causing illnesses later in life and some duct-board you cannot clean inside vs flex duct which you can. Duct-board is VERY common in Florida and Texas.
I had some quotes from large, reputable companies who I later found out did not use any of the above standard, expected techniques but were just very good, flashy salesmen (some companies only pay their technicians based on commission!!!).
GOOD LUCK again.
