Leaking indirect water heater and inefficient AC
I’m buying a house near Worcester, MA, (zone 5). The house has two floors and a walkout basement. It has leased solar. It’s heated by an oil boiler with an indirect water heater. The boiler and water heater are from 2015, but the water heater was installed with some slight leaks and has corroded to the point of needing replacement. Additionally, the house has an AC system in a conditioned attic. The AC is a 10 SEER Goodman unit from 2018.
I’m trying to come up with a 5-year strategy for HVAC improvements. I would like to stop burning oil. I’m also planning on insulating the basement, which will mean moving the existing radiators. I have a bunch of different potential plans.
1. Do nothing but repair what’s already there. Replace the indirect tank with a like unit. Replace the basement radiators with like.
2. Prepare for an air-to-water heat pump. In the short term, replace the indirect tank with one that is compatible with a heat pump. Longer term, replace the boiler with an air source heat pump, and replace/retrofit the attic unit with a ducted hydronic coil. Use the radiators for primary heat. Use the attic unit for cooling and backup heat. Install a fan coil in the basement for heating and conditioning.
2a. As above but convert the attic unit to an air source heat pump for backup heat.
3. Prepare to move away from hydronic heat. Replace the indirect tank with a heat pump water heater.
3a. Eventually: Install a new ducted air-source heat pump to heat and condition the first floor and basement. Replace the attic unit with an air-source heat pump to heat and condition the upstairs.
3b. Eventually: Use minisplits everywhere to heat and condition the house.
3c. Eventually: Use minisplits on the 1st floor and basement, but replace the attic unit with an air-source heat pump.
What should I take into consideration when planning this out? Am I missing better ideas?
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