I think my HVAC system could be oversized. Is this something I should be concerned about?
I think my HVAC system could be oversized. Is this something I should be concerned about? (post #206612)
I bought my new HVAC system just over 2 years ago. The furnace is a high efficiency natural gas that vents through pvc pipe through the wall. The furnace is rated at 45,000 b.t.u.'s. In the winter, it feels like my house is either hot or cold regardless of where I set the temperature. I try to aim for about 68 in the winter.
My AC is a 2 ton unit with 3 ton evaporator coils. It usually feels either hot or cold in the summer. If I set the temp on the thermostat above 74, it tends to feel a bit clammy. Sometimes I set the thermostat down to 73 or 72 just to get it to run. I'd say most days it probably runs for less than 10 minutes, then shuts off.
I live in Iowa, so I have a mixed humid climate. I also live in a well-shaded area, under 800 square feet of conditioned space. Air tightness is pretty good. I think I've sealed up most of the major sources of air leaks and my insulation is fairly good (in the attic at least, not so much in the walls). I don't notice much of a difference in the running time of the HVAC system before and after some of the insulation/air sealing. It seems to run roughly the same, only the difference is I can keep the temp a little higher in the summer and lower in the winter (but still uncomfortable, either hot or cold).
Am I being too picky here or is this not working out as it should? I'm not sure what else to try. My ductwork is pretty old and poorly done (have a thread about that right now) and most rooms one supply register is in the wall split between two rooms. Would re-doing this just make my system more efficient and possibly more oversized or could it possibly help? Is it possible to put a variable speed fan in that makes the system run slower for longer without having to change out the whole system?