Hi again!
We just finished refinancing our condo ($300/month savings with PMI gone and better interest rate, woo!) and finished renovating it as well to the tune of $25,000 (mostly parts, 90% of labor was my own except a tiling contractor)
So now I want to tackle any inefficiencies in my energy scenario:
-We live in SoCal. Mild winters, hot summers. Lows of 0c (32f) and highs of 43c (110f).
-Condo was built in 1982. The in-closet furnace and outdoor central AC condenser are all original. Thermostat is new and electronic, programmable $25 unit from home depot. The NEST sure looked nice, but not for 10X the price!!
-Condo is 2-story, 1250 sq feet
-All original insulation, so not that great
-All new dual-pane glass all around the house
-Gas tank water heater (original)
-Original AC condenser
-Gas stove
-Furnace stays on keeping a decent sweatshirt temperature for 2 months out of the year
-Air conditioning stays on keeping our pets alive and us cool 2 months out of the year
-8 months out of the year neither the furnace nor the AC are used at all. We just open the windows
-When either the furnace or the AC is used, our utility bill is around $90
-When we use no environmental controls, our utility bill is around $60
So the questions I have are:
1. Should we replace the aging/inefficient furnace with a new unit? $unknown thousands to be spent vs unknown savings
2. Should we replace the aging/inefficient AC coils and condenser? $5,000 to be spent vs unknown savings
3. Should we replace the aging/inefficient water heater with a tankless gas-fired system? $500 parts +200 labor for install, plus recycling fee for tank so let's call it an even $1K to be on the safe side.
4. Should we do absolutely nothing? We do not intend to stay in this condo for more than 5 years.