|super insulation||Northern Light|
The concept of "superinsulation" is controversial, with differing opinions and conclusions offered by thoughtful, well meaning people. As the physics, metaphysics and culture of housing is complex, requiring many subtle compromises, this information is presented to generate interest and discussion.
(One Story) Super insulation was a hot topic first in the late seventies and early eighties if I recall correctly. Before that, oil was so cheap, and tradition so strong, that insulation was not an issue, many houses were not insulated at all. It was determined by research here and there that massive amounts of insulation (contained in double wall systems for example) combined with an air barrier of some sort, resulted in a house that almost heated itself from appliances and body heat. Solar energy (most folks were into complicated active systems at that time) became less of an issue, because very little supplemental heat was required. Windows could be placed just about anywhere (if well sealed, double paned and small), without significantly effecting the efficiency.
Not many "superinsulated" houses have been build because most houses are built by resellers who don't care because someone else (the buyer) pays the utilities, and the general house buying public is uninformed and easily manipulated. The superinsulated house costs significantly more in initial costs (double wall construction), does nothing for the curb appeal, thus has a negative effect on sales. Besides, energy costs remain relatively low because of subsidies. And the myth, that a house can be too well insulated and sealed (in 4 season climates) has persisted. Without a well sealed house, the insulation is bypassed through leaks, and rendered less effective.
Fortunately, the green builder movement is taking hold, moving into the main stream, resulting in reasonable levels of insulation, better control of infiltration, tighter houses, easier and more comfortable to heat, cool and maintain (and energy savings). Super insulation can be achieved without expensive double wall systems by adding insulated sheathing to one or both sides of conventional frame construction (2 by 4 or 2 by 6). It turns out that the sealing of the house is just as important as the insulation, and much easier and cheaper to achieve...but builder resistance remains strong.
Straw bale construction by its nature is "superinsulation", and is easier to air seal, particularly when slab on grade and plastered. Costs remain a bit higher because thick walls require more foundation and roofing materials, and plaster can get expensive unless you do it yourself. Don't forget the other benefits of straw bale (superinsulated) construction such as superior livability in terms of sound dynamics, charm, and spirit.
Even with superinsulation, and good sealing, Straw Bale houses will probably require supplemental heat and maybe cooling, depending on your climate and acquired personal comfort zone. Certainly, the building code will require a substantial heating system regardless of your insulation levels. The energy savings with well sealed superinsulation can be very substantial, but is greatly effected by levels of energy awareness, life style, design and detailing.
Please, if you have a perspective, comment or information that will add to this feeble introduction please send them along and I will include them here under your byline. Thanks, Robert.