I have finally narrowed my decision down to this one contractor. I am going to do a Goodman Heat pump with a back up gas furnace(my house is under wired to do electric back up). I would like some advice on which to choose option 1 14 SEER heat pump with 80% AFUE furnace and 4" media filter price after ameren rebate and tax credit $3946 option 2 same as option 1 but with a 95% AFUE furnace price after ameren, laclede, and tax credit $4268 I think I might as well spend a few hundred more to get the better furnace. It will look better when selling. So my main question I can uprgrade to a 16 SEER heat pump after all rebates for an additional $556. The guy said it would only save me about 10% more in my utilities so it probably wouldn't be worth it to spend the extra to upgrade but I was just curious if that would he better. I will probably only be in the house for another 5-10 years but that isn't for sure. It could be a little longer.

Mike, yes. They have to give me the wired ODT sensor so I can lock out the heat pump. This was discussed between them and I several times before I signed on the dotted line and they had assured me this was possible. So as far as I am concerned they have to deliver on it even if it required ODT sensor. I just found another issue as I dig into this mess. I was trying to understand the fan behavior. In particular, from the sound it seemed the fan always ran at one speed. I was puzzled and digging into the thermostat menus, I confirmed this. The fan was either 100% or 0% speed. And it runs for additional 1 minute or so after the compressor shuts off (cooling fan delay). I found this odd - why did I buy a variable speed blower and why was I sold one. I mentioned this to the dealer and could get a satisfactory explanation. And then I checked the install guide - and it was there (see attached, in particular the graph and the table). There are four settings one can choose from. To really benefit from the variable speed the jumpers on the inside unit need to be configured in so called enhanced mode (option 4 in the table) where the fan starts at 50% speed and then to 80% for about 1 minute (fast cooling); the fan then stays on at 80% for 7.5 minutes (dehumidification); if necessary, ramps to 100% to get to the set point temperature and stays there as long as required, and ; ramps down to 50% and then 0% over three minutes to extract extra cooling efficiency. Well, this is not how my system has been configured. Mine is configured as option 2 in the table - 100% fan speed, followed by 1.5 minute delay - there is no variability of fan speed that can kick in. I have call in to my dealer...

I suggest separate systems for the first and second floor. That is the best way to have even temperatures on each floor. It costs more up front, but you potentially have lower operating costs. You could zone the loft off the second floor system. However if you are going to be working 10 hours days with multiple pieces of equipment generating heat then spend the money on a mini split.

Variable speed does not necessarily mean single stage. Variable speed alone will not mean much for humidity. A typical upcharge for a single unit going form Seer 14 to 15 in the 4 ton range is $400 wholesale. 4 tons? That is most likely a bigger problem than anything else. I am building 3700 sqft and trying to make 2 tons work but I'll probably settle for 3. 4 tons full force will cool your house in 5 min and then shut off not giving anytime to dehumidify. Now - if you have large western windows, you might need it. Western windows drive the a/c load so much. A large window can be a ton in load by itself. 100k btu is less of an issue but my current 5,000 sqft house built 2010 had about 45k total load. I'm sure Baltimore gets a little colder but still. You pay a bit for 2 stages and will use that higher stage only when you get back from a winter vacation. I looked back - you are 2 stage on the furnace but no comment on stages on the a/c. It is possible that the SEER upgrade includes upgrade to 2 stage. I don't know a lot about Nest - I've heard they are garbage. Programmable, wifi stats are very common but the Nest is cute. Setbacks aren't as clearly helpful as you might think. They are helpful but for a tight house, a/c setbacks can hurt. Usually not but they aren't that helpful either.