Re: In Need of a new Heat Pump and outdoor A/C
I'd look at smaller HVAC units. I don;t think the indoor units are significantly larger. The coils are a little bigger but not a lot. To minimize size, make sure you get a load calculation done and install the smallest unit possible. You could also invest in better insulation and sealing up air leaks in the house by getting a home energy audit and finding them.
The temperature imbalance is typical in a 2 story home that doesn't have zoning. Adding zoning is pretty expensive even if the main trunks are accessible. You'd need a 2 stage AC and on top of the zone controls.
However, you might be able to minimize the difference. Typically a house that is warm in the summer upstairs is also warm in the winter as well. IF it's also old in the winter, then you are short on airflow upstairs.
ALSO... upsizing the AC to fix the imbalance will actually make it worse. Smaller equipment heats more evenly because it runs for a longer time. I'ts estimated by some that 1/2 the homes in the US have oversized HVAC equipment.
A 2 stage furnace will also heat more evenly and s worth the money in a cooler climate.
DO oyu have a dual fuel system (heat pump & gas furnace) or a heat pump and air handler?
Finally, to improve airflow upstairs, you can install higher quality supply grills on the upstairs registers. They cost 2-3x more, but have better throw (air distribution) and less resistance. So you'll get more airflow upstairs. Atlanta Supply is 1 place you can buy them ******.
1925 Two-Story Stucco Beaux Arts Neoclassical