Posted to cosdreamhome by Arnold in Colorado Springs, CO
on 5/5/2008 7:10:37 AM
One of the desires for our building project was to build a VERY efficient home. (I'm not a typical O-B, I'm in this one for the long haul.) With our concentration on the energy-efficiency aspect we kept trying to find some software or supplier that could quantify how their product would help our efficiency. We didn't find anybody who could model the types of homes that we were building.
In order to attempt to alleviate some of the confusion, my buddy PJ (smelltheforest) and I have been tracking the performance of our new houses and we're sharing it with the attached PDF.
The metric we're using is 100% made up by us. In order to try to compensate for climate, we're using the metric of heating days (more here) per BTU and then dividing by square footage to try to handle the different square footage of the homes involved. This is NOT a perfect metric. But it does show remarkable consistency, which gives us hope.
A little bit about the houses:
AG -- My house is ICF walls up to the top of the second floor joists. From there SIPs are used, and SIPs make up 80% of the roof, with 20% trusses. The trussed sections are insulated with Icynene sprayed up against the roof deck. Heat: garage and basement slabs have radiant embedded in them. All other floors utilize thinset gypcrete over a normal subfloor with radiant in the gypcrete.
PJ -- Identical to above, with the exception of extremely limited SIPs (mostly scissor trusses with Icynene sprayed against the bottom of the roof deck). Also has insulation under the basement slab.
ME -- A conventional house, insulated with spray polyethylene foam. Roof insulation is done using polyurethane foam against the roof deck with fiberglass batts covering the polyurethane to prevent noxious gasses. Radiant is staple up. Garage is not heated, basement slab has radiant embedded in it.
Avg 1998-2006 -- A cookie cutter house constructed with 1997 technology. Fiberglass batts, blown in fiberglass on the upper floor ceiling, and forced air heat.