A wall that is seldom mentioned is a 2" x 8" double stud wall. I have used this for new home construction and it is easy to build. Staggered 2" x 4" studs, 16" on center with common plates. 2 layers of R-15 insulation and 3/4" fiberboard sheathing will put the overall wall assembly close to R-30. House wrap and a rain screen underneath the siding will allow the wall to dry to both sides with MemBrain or the like as the interior air barrier.
Posted: 11:02 am on April 17th 2018
Michael, I agree that there is not much of calculated thermal advantage to the double stud 2 x 8 wall. Framing with all 2 x 8 lumber is expensive and typically 2 layers of 3.5" insulation will be less expensive than an 7" batt. The cost savings on material should offset the additional labor for the double stud wall. What I have described is a very cost effective and high performance wall that dries to both sides using common and cost effective materials. There is no splitting of insulation batts for electrical wires as they can run between the studs.
Posted: 12:07 pm on April 17th 2018
Wave Of The Future It is good to know a very energy efficient house can be heated comfortably by minispilts in northern MN. The Midwest is about to enter a wind farm boom in the next several years so there will be a lot of wind generated electricity available for heating homes. Large transmission lines have either been completed or are nearing completion to link the wind farms in ND, SD and MN to the grid. Many existing homes will need an energy retrofit to take advantage of the minisplit efficiency.
Posted: 10:45 am on April 18th 2018
Minisplit Efficiency Elden, Following John's comment, have you any estimate as to the efficiency of your minisplit system? What was your kwh use for heating with the minisplit vs heating with electric baseboard only?
Posted: 11:49 am on April 18th 2018
Industrial Agriculture vs Regenerative Farms Biodiversity on the farm is the answer to sustainability and even better, regeneration. Regenerative agriculture is the new game in farm country and is gaining favor due to the economics of modern farming, high and endless input costs. Putting carbon back in the soil is a sure bet for landowners and for the environment. Diverse native plantings benefit consumers, landowners and all creatures. The opportunity is vast in the Midwest to return marginal cropland back to it's original cover. Massive amounts of carbon can be sequestered in the soil with a diverse planting of very deep rooted prairie species. Crop rotations including cover crops for soil fertility are gaining favor over synthetics. Growing your own fertility takes us back to the homestead days, returning as much to the soil as you take out each year. https://rodaleinstitute.org/regenerativeorganic/?gclid=EAIaIQobChMIldiG587G2gIVSdbACh0p0gowEAAYASABEgJUzfD_BwE
Posted: 11:13 am on April 19th 2018
Uniformity In Energy Audits I am working my way through this study and it appears to be very well done. Utility sponsored energy audits generally do not allow enough time or money for the energy rater to do a comprehensive energy use analysis. Energy bills must be studied, square footages established along with building specifications. From this an energy upgrade priority checklist can be made along with a replacement schedule for HVAC and other degrading elements.
Posted: 10:10 am on April 21st 2018
Canada has a different grounding requirement (grounding strap) than does the US. We do not offer a Canadian compliant product at this time.
Posted: 11:11 am on April 26th 2018
I second the recommendation by Martin. Air space, fiber insulation, (2) 1 1/2" layers of polyiso with seams staggered and taped to the underside of the rafters. I would then add some pine strapping to the underside of the rafters for the drywall attachment. Much easier than trying to install drywall directly to the foam with long screws.
Posted: 11:32 am on May 17th 2018
I attach pine strips to the top side of each rafter (tight to roof decking) for the desired air space depth. To this you can use fiberboard or OSB as your vent material fastened to the underside of the pine strips. We just finished an ice dam solution project and used the same detail, dedicated air space (1 1/4"), reused R-28 fiberglass insulation to fill the rafter space and 3" of polyiso foam (R-20.3, all seams and edges foil taped) attached to the room side of the 2 x 10 rafters.
Posted: 12:48 pm on May 17th 2018
Thank you for this very in depth post on building in CA, the chart on airtightness, PH vs code is quite dramatic.
Posted: 12:30 pm on September 25th 2018