So your original thread for my response.

Changing my fan speed last year (it was set on the highest) combined with a much friendlier weather pattern this year. My humidity is in the 48-52 range. Last year I had it in the high 60's! Last year the winter/spring were incredibly wet. Even my basement has lower humidity this year, so I think the weather had a lot to do with it. I have conventional ac, but it was ME who figured out that the wire that was hooked up was for the highest fan speed when ac was in high (I have multi speed, not variable speed). I told the tech that I thought the wires should be switched because my fan was set too high, my blower is sized for my heater-which is bigger than my ac. FIgured it out by reading this board and learning that too fast cfm means less time for moisture to be removed, then I READ THE MANUAL. Much like the OP has done. I showed the tech (the experts they sent out when the first guy had no clue). This year my doors aren't sticking. I think this is the least they've ever stuck (in the summer). Sometimes I think it's TOO dry (according to my throat/nose in the morning) but it might be allergies. Yes, Homeowners shouldn't mess with things, but if we do we need to be sure to document what the original settings were so we can fix our fix if it doesn't work. (take a photo, or draw a diagram) Some of the charts and diagrams are pretty easy to understand. I wouldn't touch anything if I weren't certain. My humididty might be even lower if we kept our garage doors closed all day and if we shut the front door. We let the dog look out the storm door, but it's a pretty good seal.

schmidt first to answer your last post. unless this is an emergency, I would want an R-410a refrigerant HP with matching coil. Your situation is not as simple as it might appear. several questions. 1.your existing AC condenser is three tons? and sometimes at extreme outside temps it does not cool adequately? Pls confirm 2.What is model, size, apprx age of existing furnace? 3.And the blower motor's rated size? Very important. You will have problems if you go up in size with a 3 1/2 ton HP with a furnace that has only a three ton rated blower motor. I hope you realize that with the XL14i or XL15i you will not achieve its rated eff/performance potential with a mismatched non var speed furnace. Anyone who says otherwise is simply blowing smoke. If you go from a three ton to a 3 1/2 ton, your ductwork has to be sized correctly for good airflow. This should be verified. Trane HPs while very reliable but are light in heating BTUs for its rated size-all but the XL15i. Just so you know. For me, the XR13 or XR14 HPs in R-410a would be better choices than the XL models unless you intend to replace furnace in very near future with a matching var speed model. There are good options other than Trane such as Carrier Comfort series HPs. IMO

@mike_home: I acknowledge I don't know much about SEER and EER and such. I thought it was 14 SEER because the unit's nameplate says XL-1400. The invoice covering the GP CheckMe! efficiency test is hard to read, but it looks like it shows 'New 11.29 / 8.95 Actual' whatever that means. It's my understanding that GP normally pays for up to 2 lb. of Freon to bring a unit up to par for the efficiency test. I didn't know about that and had already had my unit recharged before scheduling the test. The servicing tech gave it an extra boost to make it last a little longer in view of the continuing leak, and so the service tech who performed the efficiency test actually removed Freon to bring it down to proper charge level. The tech and his boss insisted that the charge had to be at the proper level before the test could be performed, so no, I did not have the option to have the test performed without having the proper Freon charge.