I have a cautious buyer set of questions that I'm hoping to get opinions and options on.
1) I have a townhouse with a backyard that is only 28' x 29'. To constrain it further, I have a 3' high floating slab deck off the rear that covers all but 3' on each side of the house and protrudes 6' out. With a 4 ton and a 5 ton unit in the backyard, it makes it very difficult to land and hardscape around the units. I've been looking at the Carrier Performance Series Compact Central Air Conditioner. My thinking is that I could put the two units between my deck and fence (3' wide area). Does anyone have any experience with these units that you can share? How compact can the installation area be? Are they dependable? Could the actually be installed underneath the deck if there is enough height? Elevating the units to the roof is not an option.
2) I know that decible levels are not linear and that 60 decibles is the sound of the inside of a home, 65 is the same as a busy office. Because of my limited area, I want to reduce noise as much as possible. I'm looking for references that put decible levels in relative terms that are understandable and what the impact is if you have two things putting out say 75 decibles. Is the noise doubled? Any references would be greatly appreciated.
3) SEER rating seems to be a huge marketing gimmic based on the payback period for incrased unit cost. From what I've seen, buying a 13 SEER unit for $ vs. a 16 SEER unit for $, saves me only $.29 a day at $.10 per kilowatt - making the payback period about 14 years to cover the $ difference in price. Of course, all installers push high SEER ratings. Am I correct or am I missing something?