Over two years ago we had a factory authorized dealer replace our dead furnace with a heat pump system with electric backup. This work involved reducting all rooms in the lower level. The new heating system isn't able to heat the lower level above the mid 60s. After two years of reminders, the dealer walked away from the job with the excuse that the house can't (!) be heated.
After consulting with 3rd party experts and doing a load calc, it appears that the new ducting doesn't move enough CFM for heat pump use and the heat pump is undersized for the entire house. If the ducts were adequate, the HP balance point would be around 40 and the remaining 47,000 btu needed to heat the house at the design temperature for this area would need to come from the electric backup. The electric backup is only capable of 34Kbtu (10kw). To lower the balance point to 32 would mean replacing the existing heat pump with a 5 ton unit.
What should I be asking for when getting fix-up bids from other contractors? I've come up with four options but am looking for advice on which way to go next.
1. Fix ducting + replace the existing 3 ton heat pump / coil with a 5 ton heat pump / coil. This is probably beyond my budget.
2. Fix ducting + upgrade heat strips to cope with design temperature? If I do this, I'll be paying for 3,500btu of electric heat for most of the heating season and 47,000btu (!) on design days. Expensive.
3. Fix ducting + install propane furnace & ditch the heat strips.
4. Dedicate the existing HP and heat strips to the main level and install something else to serve the lower level. The existing HP is about the right size to heat the upstairs level down to design temperature w/o any electric backup. The lower level requires about 24,000btu at design temperature and about 9,500btu for most of the heating season. I'm considering three options for a system for the lower level:
4a. Electric baseboard heaters for the lower level. Will mean paying for between 9,300btu and 25,000btu of electric heat through the heating season.
4b. 2 ton heat pump for lower level w/ new duct work. House electrical service is barely enough to cope if both HPs defrost at once while every other high load electrical device (stove, water heater, oven) is on at the same time.
4c. Hydronic propane boiler system w/ radiators. The boiler would also replace the electric water heater.
Budget is definitely an issue but I'm prepared to pay more up front in exchange for lower operating costs provided the payback time no more than 5yr or so.