I am having my 4 ton Rudd condenser unit replaced on my 1400 square ft condo on the beach. It actually made it 9 years but fins are rotting off. Air handler is Goodman ARUF486016 4-5 ton installed two years ago. Contractor that installed that unit is suggesting a American Standard 13 SEER and offered a reasonable price. He has it on his shelf. Current set up is R-22 and he would leave that. Contractor 2 will match price with a York 13 Seer single speed with coils coated for coastal conditions and flush system and put in 410 freon and change expansion valve in air handler for the same price. Which unit might last the longest in a beach environment? Question 2 would it be worth going to a 2 speed 15 SEER unit for another $xxx? This is a vacation rental unit and most guests crank thermostat to 70 degrees and leave it and A/C runs most of the day.