Going all electric with ccASHP in Connecticut or stay with cheap(er) natural gas?
Our AC broke down two years ago, and we are considering switching from a gas furnace+AC combo to a greener version, a ccASHP. Good for the environment, which we love, however, with electricity prices 2nd highest in the nation and gas cheap(er) in Connecticut we are wondering how much more this would cost us. Electricity in CT is not exactly renewable, but we’re hoping this will improve.
I found two comparisons of gas furnace vs. heat pump costs in CT+MA:
House with average insulation: gas $700+/heat pump: $1,000+ (Robb Aldrich @ StevenWinter)
New 2000sf in MA: gas: $878/heat pump: $1,256 (see attachment).
We pay $900 for gas (which includes hot water), and use heat all day since my husband works from home.
So, will the heat pump cost us $300-$500 more, or will the heat pump be that efficient that we won’t be paying too much more?
Secondly, if we go with the ccASHP, mini-split or Carrier Infinity?
heating: 60,000 Btu 90 % Trane HE (still working fine/no issues),
cooling: 30,000 Btu, Trane HE; 2.5 ton condenser.
Some info on the house:
Located in Hamden, CT (zone 6), 2 ½ stories, 1580 sqft, 2 adults.
The HES, done in January 2017 when we moved in, brought the blower door test results from 2483 to 1676 cfm/50 after air sealing, weatherization and installing all LED bulbs.
We installed solar in February 2018, which covers almost all our electric needs except the electric car and cooling (AC has been broken).
In 2018, we worked on improving the building envelope and added insulation:
Attic floor: pre-existing R30 Fiberglass + 30 Cellulose added, total: R60.
Garage ceiling: pre-existing 21 Fiberglass + 25 dense-packed Cellulose added, total R46.
Garage walls: 0 + 13 rigid foam added
Walls: R19 (= max, no space to add more insulation).
We tried to get an estimate for outside wall insulation but haven’t found anybody yet who would do this. It would also mean adjusting windows, which we’re not prepared to do right now.
Despite the added insulation, the second HES blower door test in Dec 2019 did not show much improvement (1548 cfm), probably because our bathroom renovation contractor did not close the walls he was working on or the insulation guys didn’t do any air sealing in the attic.
The gas heating bill did go down about $170/year (from 685 to 577 CCF).
We were hoping to use our current duct system for the heat pump, although mini-splits may be more efficient, and Asian manufacturers don’t usually use those ducts (Yes, I’ve been reading quite a few of your articles here).
So, here are some of the quotes we got:
Fujitsu Elite dealer (only does ductless mini-splits, not ducted ones):
Fujitsu AOU36RLXFZH, SEER: 20, HSPF: 10.3, COP: 4.
one outside unit+4 zones; upstairs: 7+7 BTU, downstairs (open floor): 15+ 9 BTU.
Total BTU: 38000. Price: $11,500 + electric work.
He had somebody do Manual J (8th ed., Wrightsoft Right-Suite software):
1st floor: 25291 Btu heating, 16971 cooling, proposed Btu: 24000 capacity to 27K (2 heads)
2nd floor: 16212 Btu heating, 14208 Btu cooling, proposed Btu: 18000 capacity to 22K (2 heads)
Total: 42000 BTU
Other estimates (include permits+rebates):
Carrier Infinity 16 SEER heat pump: $12,365 [probably not enough without furnace back-up?]
Carrier Infinity 20 SEER inverter heat pump: $18,125
Mitsubishi MultiZone Hyper Heat Pump w. 4 air handlers, 1×12, 3×9, total: 39000 BTU, $16,500
If we go with the mini-split, could we keep the current Trane for heating when it’s really cold until it fails?
In the long run, we would like to get rid of the gas hot water heater, too, but the heat pump hot water heater seems to have its own issues, e.g. make the room cooler, which would not be that great since we have our washer in the same room.
Oh, and we are keeping the old-fashioned wood furnace in case of a power outage, since we have free wood on the property and use it about 5-8 times a year when the temperature is in the teens at night.
Any help is greatly appreciated!
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