gas furnace is 80% efficient

[msimerson]

Which means it's wasting 20% of the gas paid for.

options

1. replace with high efficiency (95%) gas furnace
   • pros
     • ductwork already in place
     • highly efficient (wastes 15% less)
     • natural gas is (currently) a cheap fuel
     • 95% efficient Trane at Second Use is only $600
     • PSE rebates
   • cons
     • fossil fuel
     • natural gas price is more volatile than electricity
     • requires connection fees, even in summer months when no gas is used
     • leaks are far too common, resulting in poisonings and explosions
       • much higher risk in seismically active areas
2. replace with mini-split heat pumps (#53)
   • pros
     • new models are super-efficient (HSPF 10+) and heat well, even in winter
     • we don't use A/C much in Seattle, but 20+ SEER is a nice perk.
     • Seattle has cheap green electricity
     • uses no fossil fuels (Seattle's grid power is mostly hydro plus some wind, solar, and other)
     • pairs well with solar panels (#13)
     • zoned heating
   • cons
     • requires 220v wiring
     • higher install cost than a replacement furnace

       todo

   • [x] remove ducts from crawl space
   • [x] remove furnace from crawl space
   • [x] install heat pumps (#53)