Wanted to get some opinions on the ROI of adding insulation or new windows to my home. Home is single family ranch style, built in '63 has maybe 4'-5' blown insulation in the attic, none in the crawl space and old school single pain windows with storm windows. I bought in Sep 2015. Is natural gas heat (& hot water) and electric AC.
Looking my power bill when the AC is off (ie winter) they run 45$-50$
My gas bill when the heater is off (ie summer) run ~20$
So if I take these and look at how much higher the bill is when using the heater or AC I can see how much each costs and by extension how much could be saved with better insulation.
Electric bills: 48, 49, 49, 46, 63, 133, 164, 145, 109, 46, 45, 50 ($)
Gas bills: 82, 103, 71, 37, 22, 21, 21, 19, 21, 23, 38, 56 ($)
The cost of running the AC is: (63-50) + (133-50) + (164-50) + (145-50) + (109-50) = ~364$
The cost of running the heater is: (82-20) + (103-20) + (71-20) + (37-20) + (38-20) + (56-20) = ~267$
So heating and cooling cost 631$ / year.
Attic and crawl space insulation would run ~2k$
Windows run say 400$/each * 16 -> ~6400$
So say I did both and cut my utilities in half the pay back period is: (2000+6400)/315-> 26.5 years.
Mark me underwhelmed. Is my math wrong in some way? I would very much like to use less resources and lower my utility bills but this is a stretch.
I will grant better insulation/windows would be more comfortable and quieter. The ac does have trouble keeping up in the summer (I had it inspected it is fine-just small). Better resale value-blah-blah-blah. But 8400$ would buy A LOT of fuzzy slippers and cold beer.
Note 1: I installed a Nest last Oct so any betterment from it is only in the gas and not the electric.
Note 2: I have ceiling fans in the main rooms they are great.
Note 3: I have not had an energy audit but there are no obvious air drafts of leeks.
Note 4: For the most part no one is home during the day.
Note 5: The temperature gun shows the coldest surface of the house is the windows when the blinds are open - but they are most keep the closed.
Note 6: House is 1400 sqft.
Note 7: Roof is 1 year old and has a new attic fan.
Any thoughts are welcome. Does this line up with others math? Am I missing something? What payback period would you need to invest in efficiency?