Hello, You did very good in keeping the condenser for 20 years. It sounds like your system was installed correctly and did not work too hard during the hot months. This is important in helping equipment last longer. Todays Hype by highly advertized brands comes with a hidden cost. Lower quality equipment. Peace of mind may dictate you replacing the system now, but keep an open mind towards repair. IMO, the older equipment from the early 1980's is probably a better machine because this was before all of the cheapening of parts. Capacitors are not oil filled, which means they have a shorter life. Condenser motors are not built as well. Stuff that was originally designed for 20 years is now lasting 5-10 years. And needs repair every 2 years or so. Electronics in the system is expensive to repair. Once again IMO the older HVAC is less efficient but cheaper to operate. Newer equipment, to maintain the quoted ratings, requires larger line sets. Although fluid mechanics design has not changed in a hundred years, the newer systems need larger lines. What this means is the lines can deliver more fluid to the evaporator, and produce more cooling. Not a larger evaporator but more flow. This is a cost vs performance decision made by marketing. Shifting part of the cost of efficiency to the consumer installation rather than larger coil area and basic equipment costs. Kinda cheating on the price quoted to consumers. TRANE and other tier 1 companies are following in MAYTAG's footsteps in designing for shorter equipment life. Maytag eventally was forced to sell. They could not keep up with warrantee repairs. Typical marketing is still claiming 20 year life to explain the payback, but in reality the calculations are skewed. Rheem, York, ICP and all of the other second tier level manufacturers probably produce equipment closer to what TRANE claims they offer, but with a lower cost. Rheem has really cornered the gas modulating furnace market. The AC side is easily serviced. The units look good. Traditionally Goodman was a product that had zero quality control. Many units I installed in the 1980-1990's had a small problem. Never the same problem, but always a problem. This added time to installations. Very frusterating on a hot summer day. Goodman is the #2 manufacturer of HVAC in America. Goodman has much better Quality control today. One recent discussion was about how Goodman could meet 13 SEER without a TXV valve. No other company regularly does this. This means fewer mechanical parts that will go bad on a hot day. This $20 OEM cost part equates to about $100 less to the consumer. Adding a TXV valve increases AC efficiency and Goodman sells the upgrade part. The size of the condenser coil is larger than normal which allows this exceptionally good design. Kinda neat. I had a repair last summer on a air handler made by a small company in Dallas. 'First company" The unit did not have a schematic so I called them, hoping to get some help. They not only had a schematic, but it was tthe same design and even wire colors for more than 20 years. I was impressed. Then they told me they made product for York. I yawned on that claim. They then told ne they were a 100 million dollar company. This is not a billion dollar business, but something to be proud of. I would highly recommend thier airhandlers. They also make several models that also have hydronic and Freon coils built into the air handler, along with strip heat. The prices are very reasonable. This can allow preheating of hot water or hydronic floor heat. This is a sleeper product. The heating of floors in your climate area is very popular. Very neat IMO.

Around here (Maryland/DC area) that's about the minimum you'd pay for a decent heat pump replacement, but in general Florida sales run cheaper from what I see. You could try negotiating, but the seller may not have room to go lower all costs (company overhead, materials, equipment, labor, etc.) considered. You also won't know what corners will be cut. I did not think Payne made a variable speed air handler, so may want to check on that. I would suggest you consider the Carrier Performance line if you stuck with Carrier rather than other brands (don't know how many bids you got). The equipment upgrade costs varies depending on what the dealer has to pay his distributor. I would hope the dealer is willing to give you the equipment upgrade cost only, but often times the prices are marked up to a sort of MSRP for each unit. For a rental property, a Payne system with a 10-year warranty wouldn't be a bad choice in my opinion, but it wouldn't be the best. I like to see better built outdoor units with louvered coil protection, and Payne's units outside are more basic and low-end. If taken care of, should do the job fine.

Update: Before the install, I did wind up modifying the track in the air handler for the 1-inch air filter. I used 2 pieces of steel banding, 2 inches wide, cut to length, and placed them over the manufacturer's track using a few dabs of automobile body putty (Bondo) to keep it secure. It is now a smooth track for the filter to slide on. Goodman used the track as part of the frame of the air handler so it had some crimpings in it and the filter would not easily slide in. I also trimmed away some foil faced insulation that prevented the filter from seating properly. A 20"x24" filter now fits perfectly. I am glad that I did these minor mods as I would have been fighting this monthly when I change filters. The unit was installed Friday, 6/22, after I had it for about 5 weeks waiting on the installers. It took two guys 8 hours. I fed them both breakfast and lunch (I treat my installers well). The old supply air plenum and the plenum after the air handler had to be replaced to match the new unit. The old 5/16" liquid line had to be replaced with a new 3/8" line. 3 holes were cut into the finished ceiling and 1 in the wall so that the new line could be run. I'll repair the holes when I get a chance - no big deal. The TXV sticks out about 8 inches from the air handler. Looks funky and I have to be careful not to hit it while moving things around in that area. The old outside unit had sunk about 4 inches into the ground. I filled the hole with soil that I was saving, packed it down, put a plastic condensor mounting pad on the dirt, and used 3" thick brick to elevate the outside unit (which is huge in size compared to the old 7 SEER unit; 14 SEER = more coils = larger unit). The outside unit is much more quiet as expected but the new mult-speed air handler is also a little more quiet than the old one. The fan is set on low speed and I'm not sure of the setting of the old unit as the lables on the motor had worn away after 21 years. The sheet metal in the new air handler is flimsy and the track for the air filter can be improved by Mr Goodman. The outside unit looks decent. These comments were also noted by the installers. I plan on taking the outside and inside coils to a local scrap facility and sell the copper. Maybe I can get a few $$ for a couple cases cases of my favorite beer. I can now start saving 40% on the cooling and heating part of my energy bill and use this to combat the 65% increase in electric rates in the State of Maryland. All in all, I thought that I got a good value for the money spent (only time will tell if I made the right choice with Goodman). I got a 14 SEER system with Copeland scroll compressor, thermo-expansion valve on the air handler, hard start capacitor, 15 kw heat strip kit, bypass humidifier, and 10 year parts warranty for $2477 from a local HVAC supply shop. I paid $1200 for a pro install (needed the pro install for the warranty). Total cost was $2k less than...

Though it is 11 SEER (pretty high for 15 years old), 15 years out a heat pump, especially a Janitrol heat pump (which were not high quality units), is a good lifespan. How are your electric rates? It may be worthwhile to replace it now and save yourself a potential headache later (they tend to break when its hot or cold out and you really need them). The prices don't sound terrible, but if you keep shopping, I'm sure you can find a better deal out there--but then you may be sacrificing the quality of the installation. It's best to find a competent contractor. Many contractors will not/do not perform load calculations. They are tedious, but they are the only true way to size a system. Although you don't need one, if you didn't tell them and they still failed to attempt to size the unit properly, red flag. Rheem/Ruud is a good brand. I believe your quotes are for either a standard 13 SEER R-22 system with a standard blower or a 13 SEER R-410a system with a high-efficiency (though still not variable-speed) blower. I don't have the data in front of me right now. Other people's prices often reflect their location and the overhead/price markup of their contractors. I would get a couple more estimates if you decide to go through with the replacement. I would recommend a setup similar to the ones you've been quoted--R-410a, 13/14 SEER, and variable-speed blower. It is good that the contractors took note of the need for altered ductwork. I hope this is of some assistance to you.