A different approach to the way Energy Star has directed us to go!

This past year Energy Star has published a new version of the way they score homes and determine their HERS score.  I wrote a few topics about how homes were scored in a recent blog.  Energy Star recommended builders to now start using R-10 exterior foam in the areas below ground level.  I have always been a believer in using minimal insulation below ground level to allow the heat transfer to occur vs this newer version of the R-10.  My philosophy is our ground temp throughout the course of the year in MN runs around 55 degrees.  Frost in the winter and hotter temps in the summer play a factor in this going up or down as you get closer to the surface of the earth, but the average temp is pretty consistent.  My argument to them is that with this 55 degree temp we have below grade, we can use this to gain heat in the winter and lose heat in the summer months.  It is a free way to allow the heat to transfer and by adding more insulation to the exterior block or concrete wall we are eliminating this from the equation.  The same holds true with the under slab insulation and they agree with this.  It is recommended not to install 2 inches of foam below your concrete unless you are installing in floor heat with water piping under the concrete.  My solution to the dilemma fell on deaf ears, but I feel it is the best possible option.  I believe we should have the 2 inches of foam installed on the block or concrete wall just 12 inches or so below ground level.  After this point, we would be much more efficient running the same 2” of foam at an angle 4’ away from the home.  I would then carry only 1” of foam down to the footing of the home.  My only logic for keeping the 1 inch of foam running down the wall is to make a condensation point for water on the exterior of the block or poured wall.  Basically what I’m trying to create is a constant wall temperature along the block or poured wall in the lower level.  The 2” in foam angled away from the home prevents frost or heat from entering the ground vertically and allows us to maintain a constant 55 degrees along the vast majority of the outside of the wall.  I’m happy to present this diagram to anyone interested in seeing it.  I truly feel it is a better way to incorporate the ideas Energy Star has pushed into the new version.