1.5 story house indiana (long)

[wendortb]

My wife and I live in a 1.5 story house in Indiana that was built in 1994. The insulation isn't the greatest in several locations and I see some room for improvements. Whatever I do I have to have a good ROI or the wife won't approve it. I am trying to come up with a plan off attack.

The house:

1500 sq ft 28x36 rectangle house, 2nd story has cathedral ceilings and knee walls. I hit my head all the time on the cathedral ceilings.
Slab foundation with 1 concrete block as the bottom part of the wall. Sills sit on top of this block.
2x6 walls with R11 faced fiberglass and 1" foam sheathing and vinyl siding.
2x8 cathedral ceiling on 2nd floor with R19 faced fiberglass that allows air to pass through them for a vented roof.
2x4 knee walls on 2nd floor with faced r11 fiberglass
Eave and ridge vents along entire length of house.

80% propane furnace with ductwork that runs from downstairs, into unconditioned attic(behind knee wall) then splits behind knee wall with metal duct and has insulated flexible ducts coming off of the trunk.
Central a/c is a 10 seer unit.


Things I have done:
Sealed alot of the ductwork that I could reach with mastic and metal duct tape. I can tell I still have a negative pressure on the house but can't find those leaks.
Added metal roof and fanfold insulation on top of existing shingled roof. (I wish I would have added 1-2" foam at that time)
Sprayed cellulose insulation behind knee walls to add insulation to ducts and approx 6' of 1st floor ceiling. (I hoped this would also slow the air flow from under the knee wall, but then I read it won't stop much air being loose fill.)
Caulked/touch foamed - outlet boxes and windows and doors.




I have been using the builditsolar insulation upgrade calculator to figure out what upgrades will pay for themselves in a relatively short time.

Areas for improvement:
1. Concrete block on top of concrete slab: According the what I have read, this block is only an r1 and there is no insulation, just drywall covering it. According to my calculations, I should make my money back in 1-2 years by insulating this. I was thinking about Insulated panels over the block, butted up against the existing insulation, and digging down into the ground to get a little below ground level with them. The block is exposed 6" all the way around with the foundation exposed another 6" in most spots.

2. Walls: The 2x6 walls seem like they are being wasted with so little fiberglass in them (r11 + r5 foam). I thought about having someone blow cellulose in them by removing the vinyl siding, drilling holes in the foam, and dense packing. If my calculations are correct, I should be able to make the money back on this in 3-5 years and save $100 a year on my heating bill. Later, when we redo the siding, I can add another inch or 2 of foam board on the outside to further insulate the walls.

3. Cathedral Ceiling: R19 ceiling when they call for R49 is quite a difference. Also, from what I have read the fiberglass is losing most of it's heat because the attic ventilation is going right through this fiberglass. I have looked at several options and am thinking about either
1" air space/1" foam/cellulose filled/1" foam over rafters/drywall
OR
1" air space/3 layers of 2" foam/ 1" foam over rafters/drywall.
Closed cell spray foam would get me closer to r49, but from what I have seen it would be 5K or more to have this done and I would never make the money back.
The problem with convincing the wife on this one is i technically have r19 and would be upgrading to r28.9 with cellulose/ r36 with rigid foam. Using the calculator I would only save around 70/100 per year and it would cost 1300/2500 respectively. The payback becomes 27 years/42 years. That is a long payback time to convince the wife for such a big project.
Before the recent upgrades, I would get ice damming and a lot of snow melt on the upper portion of the roof. Now with the metal roof, the snow slides off before I can tell what it is doing.
Are the air leaks enough to justify doing this first?


4. Under Knee Wall:

I believe this is one of my biggest air leaks and is the hardest for me to seal. I have thought about just enclosing this area the same way I do when i do the cathedral ceiling and just insulating the roof, instead of the ceilings. This would put these holes and the ductwork in a conditioned/sealed space.

My other option to stop the air leaks is to cut foam board and stick in these holes. Accessing them would be a pain because that means either cutting holes in my 1st floor ceiling or trying to work around the duct work that is right behind the 1 knee wall.

5. Heating and a/c unit: I have thought about replacing my furnace & a/c in a few years with a geothermal unit. I figure my energy costs will be cut in half and it would pay for itself in approx 15 years. According to what I have read, the geothermal unit will last longer and be more energy efficient. The only downfall is cost. I'm estimating 15K for install (guessing). Air source heat pump wouldn't work as well because of the cold weather that we get.

Current electric rates are $0.11/kwh and propane is $2.65/gallon (last year propane was 2.29/gallon). With the improvements I have made already, my last month's electric bill(a/c) is $50 less than last years.

Thanks,
Travis