I'm getting some conflicting info from HVAC contractors and am wondering if anyone can offer any advice? I want to replace my existing gas furnace and add central A/C in my 55 yr. old, 1600 sq. ft. Cape Cod in southern Wisconsin. 3 contractors have suggested 92%+ AFUE 2-stage 60,000 BTU furnace, probably one with a variable speed fan (ramp up/down type) and a high efficiency air filter. The sales pitch of increased comfort and add'l air filtering because of continuous fan operation makes sense to a novice like me. A 4th contractor did a more thorough job looking at my ductwork (the others really didn't even look) and said that he wouldn't even sell me a 2-stage furnace. He said that because I indicated less flow from the supply in the master bedroom upstairs, the situation might become even worse with a variable speed fan - since the low speed of the initial stage might result in less or no air coming from that supply. He is recommending a 92% AFUE single-stage with high efficiency air filter. He is also recommending 80,000 BTUs because he doesn't want to drop-down more much more than 40k from the existing one. (35+ yr old furnace that says "Input 125,000 BTU, Bonnet Capacity 100,000 BTU") He said that central A/C might not do a good job upstairs. He said worst case scenario is that because there are only 2 air returns on the 2nd floor the cooling coil could sometimes ice-up due to a lack of return air. The upstairs is 650 sq. ft. of which about 240 is the master bedroom and the rest is a guest bdrm, full bath and hallway. Each bdrm has 1 supply and 1 return. The full bath has 1 supply. The guest bdrm and bath supplies are adequate airflow, but the master bdrm seems to be a bit low for a room that size even after trying to balance the system myself - the master bdrm is the farthest room from the furnace. He is recommending a 2 ton, 11 or 12 SEER A/C. The others recommended that or a 2.5 ton and slightly higher SEER. Some other things that only the 4th contractor mentioned is the supply under the thermostat should be closed or changed to a return to prevent the furnace from short cycling, and my house has an "opposite" system (returns on the outer walls and supplies on the inner walls). He said that I could also play with the door that closes off the upstairs to see if that would have any effect on upstairs temp. The 4th contractors seems more knowledgeable and upfront, but I'm more confused than ever. So my questions are: 1) Am I better off going with a single-stage furnace given the lower air flow to the master bedroom? (typically the coldest room) Or should I go with a 2-stage one? I really like the idea of the additional comfort from the continuous air flow with the variable speed fans, but is it worth the risk of a colder bdrm? 2) Is there a chance that my situation could cause the cooling coil to ice-up? And what are the ramifications (short & long term) of that? How can it be prevented? 3) In my climate will I use the A/C enough to justify the cost of a higer SEER? (I'd only envision using A/C when humid, temp over 80 during the daytime or to cool off the house at night) For example, 1 contractor bid me a Lennox 14 SEER w/R410a for only $200 more than a Bryant 11 SEER w/R22 refrigerant. 4) Are there any other options to these issues? (other than adding supplies or returns to the upstairs) BTW- The past Jan., I used about 230 Therms to heat the house with 1465 degree days over a period of 29 days. I believe that it was a bit colder than normal. I set the temp to 68 during the day and 58 at night. Thanks a bunch!

I'm having a with my heatpump unit. Thermostat set point is 69degrees and unit will keep running down to 62 degrees without shutting off. I have to shut the unit off myself to get it stop. 2 1/2 ton carrier. I have replaced thermostat with same model and still same problem