Though call for a customer. Trane makes a 60btu variable speed furance in 2 stage variable speed XV80. This furnace can be paired with single stage (2.5) ton unit or (3) ton 2 stage. It's the smallest that I know Trane makes with 2 stage and variable speed with a (3) ton drive.
Originally Posted by rk05
I have a customer home right now in which they are faced with this same thing. Home call for (3.5) ton load and they want 2 stage XR16. So would I will have to go with a (4) ton in this case. I am in the process of laying out new duct system for proper supply and return for the (4) ton system to cover what they want. Other upgrades they can't afford right now do to having replace the system. So either way you need to ensure duct work, line set etc... Is also properly sized for the system to work right and not be noisey.
I had even talked with them about upgrading insualtion and windows to lower the load on the home to get it to
(3) tons? Again due to $$$ issues with the customer they can't do and propely want to once we are complete.
So what I would do is ask the dealer you choose to run the numbers with adding add. Insulation to attic (most cost effective) and see how much load would be reduced. By going this way you might break even with installing more insulation and being able to down size the equipment to cost around the same amount? I would just ask them to ensure you get the most bang for the buck?
I had one contractor back out yesterday to go over the duct work (due to comfort issues more so than sizing). I went over his info on their manual J and they have already taken into account the future insulation and air sealing that I am doing for our basement remodel. I'm already at a R44 for the attic so not sure how much more I can physically put up there. I don't see myself ripping out the exterior wall anytime soon to insulate them so other than adding more insulation to our below grade garage I think I have most of that done.
Windows would be an item that would help down the road but the current ones are decent double pane. Going to a Low-E fiberglass would help out but that would be one of the very last improvement we do.