Terry, What you quoted is a paragraph of wishful thinking written by a cheerleader for their product, who doesn't really know what they are talking about. Here are a few things that jump out at me: "This is a reduction in heat transfer paths of 600 to 800 per cent." Imagine that you were interviewing a "bookkeeper" who told you that 2+2=5. That would be a clue that he doesn't have a grasp of even the most basic fundamentals, right? The quoted statement is the same thing: It is impossible to reduce anything by more than 100%. Anyone who is competent to analyze thermal performance understands that at a level that is as fundamental as a bookkeeper understanding that 2+2 is not 5. For this reason, I feel confident in deducing that the person who wrote that statement has absolutely no clue about what they are talking about. "The 8" exterior wall studs on red iron homes are 24" o.c verses 16" o.c. for stick built homes which reduces the load paths through the walls by 33 per cent." This is the crux of the problem. The thermal conductivity of steel is much higher than wood. I don't have numbers easily at hand, but I believe that the thermal conductivity of a typical steel stud is around ten times that of an equivalent wood stud. So, if you reduce the number of studs by 33%, you've reduced that 10x down to 6.66x, which is still a big loss, not a gain. Further, it is now common to build wood-framed houses with exterior studs on 24" centers, so the basic premise is faulty. "One thing they are all having is greatly reduced heating and cooling costs resulting from a high effective SYSTEM R value due to efficient design." That is just flat out a false statement. The only way it could possibly be true is if they tore down an existing house, and replaced with a new house that is completely identical except for having a steel frame, and then compared the two. I highly doubt that this is what they are talking about. They might be talking about people who are saying, in essence, "Our heating bills are much lower than the (uninuslated) 1950's tract house that we moved out of." Or, given what I typically see in marketing, it is not unlikely that the above statement is, "This is what we think our customers would tell us, if we asked them, which we actually didn't take the time to do prior to writing this up." It is possible to make steel structures perform well. The person who wrote the statement you quoted, in my opinion based solely on that statement, is not qualified to be able to do that. The existence of that statement as a representation of the company's capabilities makes me suspect that there in no one else at the company who is capable of it, either. Now, on to your questions: "But since I am going to be living IN the roof space, I suspect I'll want all the insulation I can get up there...rather than the system they just described??. Good thermal performance is a lot more complicated than just throwing a lot of insulation at the problem. Insulation is typically greatly compromised by leakage paths of various sorts. The challenge is controlling the leakage paths. "And will asphalt architectual shingles on 3/4 inch plywood make a difference? ( as opposed to a steel roof)." It will make a small difference. Not enough to materially change the performance of the structure.

I always enjoy threads dealing with energy-efficient homes, as our plan is to, within the next few years, build a home that is as energy-efficient as possible. Like teresa b (above) originally considered, we have thought about an ICF home and geothermal. The ICF concept is still almost unknown in our area. A few years ago, we attended a home show, and not only was ICF not represented, no one with whom we spoke knew what we were talking about. Fortunately, I have located a builder in the area who has some experience with the Logix ICF system, so I hope to speak with him in the future. Another interesting thing -- at a party last night, I spoke with a guy who has one of those Hardy (brand) woodburning furnaces, the type that is located outside the home, with underground lines connecting it to a heat exchanger located in the standard heating system. It also preheats water going into the water heater, to save on water heating costs. Something else I will consider!

How efficient do you want to be? I think the advice will differ if you're looking to achieve Net Zero or PassiveHaus standards vs the current stretch code. I'd suggest that in the northeast it's probably a poor decision to shoot for less than the stretch code requirements for insulation and ACH numbers. Going for the level of perfection that PassiveHaus demands stretches all but the most generous budgets. We opted for an intermediate level in suburban Boston; rigorous sealing of all air exchange we could find; insulation to ~R30 in the walls R60 in the ceilings with a wrap of rigid foam on the entire exterior to prevent conduction through the framing plus blown in cellulose and some spray foam depending no the area; reasonably high efficiency heating and cooling; solar panels that supply about 30% of our needs; decent, but not outrageous windows (a mix of Marvin Ultimate and Integrity), energy recovery air exchanger, etc. Our utility bills are about half of what they were in a similar size house built 14 years ago, but more importantly the house is extremely comfortable in both summer and winter. The house is built to last--plenty of 2-300 year old houses up and down our street, and I'm quite sure the upgrades for energy efficiency were quite worthwhile.

I think you are exactly right jannicone, although I whenever I consider that point, I sort of shake my head. I get that most people don't value energy efficiency like I do, and that's fine, but sometimes experience's like schreibdave's seem a bit irrational to me. Our new, roughly 2600 sq ft home will cost the same or less per month in total utility costs to live in than our current 900 sq ft home. It will also be a lot more comfortable (temperature, air quality, etc. etc.). Yes, it costs a little more up front, but the much maligned-in-this-thread payback period for the difference in cost will be well within the period of time we plan to live in the house. Most of the energy efficiency aspects we chose were not THAT expensive. I guess I just don't understand why most prefer the trade-offs required for lower initial cost, which usually means houses built as cheaply as possible (except for the granite countertops). It seems like finding the lowest possible initial cost is all people consider, regardless of the balance of cost of ownership. With the right choices, it costs much less money overall to have a somewhat higher initial cost and pay for that in the monthly mortgage payment, than have a somewhat lower mortgage payment and pay much higher energy costs every month forever (in a less comfortable house). We knew before we started building that almost no one would be willing the pay the same premium we are willing to for the energy efficiency aspects of our home if we needed to sell it. In my rural area, people regularly accept $300+/month energy bills, even on houses where the cost of sealing some ducts and adding a little insulation would pay itself back in less than a year, and the house would be more comfortable. People around here have $ for everything else in the world besides replacement windows for their leaking, single pane windows, which would start saving them money every month very quickly. I don't get it. (Apologies if I sound smug, I just don't understand "saving" money on less insulation and poor windows so you can buy a much larger HVAC system and nicer countertops.....does not compute).