[JLM]

when it's -40 degrees here for 2 weeks straight in the dead of winterland,  I say 100 is better than 60 by aboutttttttt oh say r40. Too much insulation ,  really. Do people complain their car gets too good a gas Milage. A heat exchanger and well sealed vapor barrier ,, your off to the races.  .

Folks brag about the great milage they get, but if the payback is measured in decades you need to give it a second thought.

I looked at geothermal when we built 10 years ago, but it was an extra $20,000 up front, with a 25 year payback (plus interest on the mortgage).  Caulk is much cheaper.  Even the solar I'm going with (including the special $0.24/kWh program and the 30% federal tax credit) isn't expected to break even for 8 years, not great but should help with resale and eliminate most of our electric bill even after the special program expires.

[2bigears]

 .  You just made a point ,, pink or blow or spray insulation is CHEAP.  Energy is not.
             And R-50 walls and 100 ceiling,,  your mechanical system can be smaller. Saving $$ there too.
                 Windows are holes in the walks.  What is the best window now, R-8 or 10 at the most.
          A window for Canada really should have 18 panes ,,,, ha.   The heating part is easy.
               Power is another story.  Can you believe the $$$$$$$$ to be made if a person could figure out a
           home by home power system.  A bloody fortune to be sure. Power companies cringe at the thought.

[JLM]

I understand that the best windows are about R7 (from Germany, so really expensive on this side of the pond).  Best to face them south and take advantage of passive solar practices with insulative panels to cover them when the sun isn't out.  (30 years ago we used something called "window quilts" that included magnetic seals at the perimeter.)

Currently the most viable "off the grid" residential solutions are (always plug the holes in the bucket first - super insulate/seal the house and reduce electrical loads as much as possible):

1.) Move to a mild climate, use a small solar/battery system with propane for hot water/cooking, and go cave man (give up most modern conveniences); or

2.) Use a big solar system with 2-way fuel cells and several pressure vessels (propane tanks) to store hydrogen (roughly $80k); or

3.) Try a whole house propane/natural gas generator with lots of batteries (so the generator can rest as much as possible to extend it's life).

[Kenneth Patchen]

I posed the question to the GreenBuilding Advisor and received two responses which I thought I'd share here. (In short, my contractor appears to be wrong.)

Kenneth,
The method your contractor is promoting has been used in the Northeast for several years. The method is promoted by some cellulose manufacturers.
The method is also a code violation. Building codes don't allow the use of cellulose between rafters, unless either (a) there is a ventilation gap between the top of the cellulose and the underside of the roof sheathing, or (b) there is an adequate layer of rigid foam insulation above the roof sheathing.
Some building scientists warn that the method suggested by your contractor is risky, and may lead to moisture accumulation and rot.
You can make your own decision. However, if your house will be inspected by your local code authority, you should run the plan by your local building authority first.
For more information, see How to Build an Insulated Cathedral Ceiling.
ANSWERED BY MARTIN , GBA ADVISOR
Posted Aug 14, 2015 4:54 AM ET
Edited Aug 14, 2015 4:58 AM ET.
2.
With it's foil facers the Tuff-R is a true vapor barrier, which means the roof decking has to dry toward the exterior or not at all. If it's #30 felt (or worse, an impermeable membrane such as Grace Ice & Water Shield) with asphalt shingles up there it's moisture trap, but if it's slate, wood shingles or tiles, or metal roofing on purlins it'll usually be fine.
If it IS low-permeance roof layup on top of the roof deck it's much safer to use a "smart" vapor retarder on the inteior side, and NOT foil faced foam board. If you want to keep the thermal break over the rafter edges you can cut strips of rigid foam and cap-nail it to the rafter edges, and fill between the strips of foam with split-batts (or if the contractor can figure out how to do it, fill it all with cellulose. It's easier to blow the cellulose in netting stapled to the rafters first, THEN apply the smart vapor retarder (eg Certainteed MemBrain or Intello Plus), THEN the rafter edge strips. As long as at least 2/3 of the center cavity R value is on the exterior side of the vapor retarder, the relative humidity of the entrained air at the vapor retarder will be low enough in winter that it will be fairly vapor-tight. In spring when the roof deck releases it's accumulated winter moisture burden into the cavity air with rising roof deck temps, the RH in side the rafter by goes up, vapor retarder becomes far more vapor open and the moisture is released to the interior.
With 0.1 perm shingles or worse and 0.05 perm foil facers on the foam, there is no drying in any direction at a rate sufficient to be useful- any moisture that gets into the cellulose & roof deck pretty much stays there. As long as it's bone-dry when it all goes together and you NEVER get even a minor roof leak it'll be fine. But requiring perfection over the long term is too much to ask for.

...............
Thanks all,
KP

[Atlplasma]

I understand that the best windows are about R7 (from Germany, so really expensive on this side of the pond).  Best to face them south and take advantage of passive solar practices with insulative panels to cover them when the sun isn't out.  (30 years ago we used something called "window quilts" that included magnetic seals at the perimeter.)

Currently the most viable "off the grid" residential solutions are (always plug the holes in the bucket first - super insulate/seal the house and reduce electrical loads as much as possible):

1.) Move to a mild climate, use a small solar/battery system with propane for hot water/cooking, and go cave man (give up most modern conveniences); or

2.) Use a big solar system with 2-way fuel cells and several pressure vessels (propane tanks) to store hydrogen (roughly $80k); or

3.) Try a whole house propane/natural gas generator with lots of batteries (so the generator can rest as much as possible to extend it's life).

If you are ever in the market for a great door or window, consider Intus (made in Lithuania). Its standard UPVC window offers R-6. I have one of their mostly glass entry doors, and it is R-7.7. Excellent product for about half the cost of a German-made window or door. In fact, my door was only a couple of hundred dollars more than a Thermatru, which is considered a high-end US door. Quality-wise, the Intus was much, much better.

[Atlplasma]

I posed the question to the GreenBuilding Advisor and received two responses which I thought I'd share here. (In short, my contractor appears to be wrong.)

Kenneth,
The method your contractor is promoting has been used in the Northeast for several years. The method is promoted by some cellulose manufacturers.
The method is also a code violation. Building codes don't allow the use of cellulose between rafters, unless either (a) there is a ventilation gap between the top of the cellulose and the underside of the roof sheathing, or (b) there is an adequate layer of rigid foam insulation above the roof sheathing.
Some building scientists warn that the method suggested by your contractor is risky, and may lead to moisture accumulation and rot.
You can make your own decision. However, if your house will be inspected by your local code authority, you should run the plan by your local building authority first.
For more information, see How to Build an Insulated Cathedral Ceiling.
ANSWERED BY MARTIN , GBA ADVISOR
Posted Aug 14, 2015 4:54 AM ET
Edited Aug 14, 2015 4:58 AM ET.
2.
With it's foil facers the Tuff-R is a true vapor barrier, which means the roof decking has to dry toward the exterior or not at all. If it's #30 felt (or worse, an impermeable membrane such as Grace Ice & Water Shield) with asphalt shingles up there it's moisture trap, but if it's slate, wood shingles or tiles, or metal roofing on purlins it'll usually be fine.
If it IS low-permeance roof layup on top of the roof deck it's much safer to use a "smart" vapor retarder on the inteior side, and NOT foil faced foam board. If you want to keep the thermal break over the rafter edges you can cut strips of rigid foam and cap-nail it to the rafter edges, and fill between the strips of foam with split-batts (or if the contractor can figure out how to do it, fill it all with cellulose. It's easier to blow the cellulose in netting stapled to the rafters first, THEN apply the smart vapor retarder (eg Certainteed MemBrain or Intello Plus), THEN the rafter edge strips. As long as at least 2/3 of the center cavity R value is on the exterior side of the vapor retarder, the relative humidity of the entrained air at the vapor retarder will be low enough in winter that it will be fairly vapor-tight. In spring when the roof deck releases it's accumulated winter moisture burden into the cavity air with rising roof deck temps, the RH in side the rafter by goes up, vapor retarder becomes far more vapor open and the moisture is released to the interior.
With 0.1 perm shingles or worse and 0.05 perm foil facers on the foam, there is no drying in any direction at a rate sufficient to be useful- any moisture that gets into the cellulose & roof deck pretty much stays there. As long as it's bone-dry when it all goes together and you NEVER get even a minor roof leak it'll be fine. But requiring perfection over the long term is too much to ask for.

...............
Thanks all,
KP

I'm glad you were able to get a response over at Green Building Adviser. Martin Holladay is widely respected in the build-science industry. As he and KP suggested, moisture inside an enclosed space where there is a food supply for mold has to be avoided. Both responses offer suggestions that would allow drying to the inside, which would put you in a better position to manage moisture. When I was building my house, I discovered that contractors often had regular practices that were based on bad and/or outdated information. In my state, licensed does not mean competent. It sounds like that is the case were you reside as well.