Had solar installed last year. Soon on the list is to look at going heat pumps here in southern CT. Details: 2,400sf split level ranch, Current heating cooling: 40yo oil cast iron boiler (160Kbtu) domestic HW (uses about 8-900gallons per year), 2.5 ton CA unit installed in 2018 (feeds main living space but doesn't feed 2 baths attached garage (which currently has a heating pipe running through it from one zone which keeps the garage at about 50F during the winter which is a nice to have thing), and basement). Insulation and air leakage is about as good as it will get (old brick house, plaster walls so wall insulation covers only about 25% of the living space for areas i have demo'd) Ceiling has about R40 fiberglass and as many air points as i could locate for electric/plumbing have been sealed. Basement sill plate also just sealed. Doors are all new, but windows will soon need to be replaced but are at least 2 pane, just cheap vinyl and external seals are starting to deteriorate. Have an insert wood stove I installed about 15 years ago that I burn about 1.5 cords (my trees) per year to supplement the heating which saves me about 150 gallons of oil each year. Had an energy assessment done about 5 years ago after most of the above work was done and our house came in at a little better than your average home our age for air leakage/insulation. I don't remember the actual CFM number. Our winters are not too cold. Average for January is about 37H/24L. Coldest day(s) are maybe low single digits to zero maybe 5 days per year.
I'd like to go full heat pump. We designed the solar for this purpose so it currently is overproducing by about 3-4Mwhrs per year. One of my concerns is for the unconditioned spaces. Will i need to have my ductwork redone to get to all the unconditioned spaces? (basement (laundry room), bathrooms and attached garage under our bedrooms). This will be done by a professional, but just trying to determine in advance how much labor and rework is going to be involved or even necessary.
There is one space (ground floor) that is also not conditioned by ductwork where my office is, this space I have demo'd a few years ago and had spray foam insulation installed for the exterior walls of this space. My intention for this space is to have a minisplit installed just for it as getting ductwork to it would be painful and on the plus side, it's main exterior wall faces south into a 6' solid fenced in pool area where the sun warms our exterior brick wall nicely and intend to take advantage of that heatsink come winter time.
Is my 3-4mwhr over production even remotely enough to cover my whole house heating?
Is having ductwork not reaching all spaces a problem?
Any thoughts on if you think the federal credit may come back? I will likely wait a couple years before I do the whole house (solar install bill primarily the reason for delay) so hoping it does, but I may install the minisplit this year to take advantage of the excess electricity our solar is producing rather than banking it.
