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After weighing a lot of different options for the construction type we wanted to use, we settled on structural insulated panels (SIPs). They've been around since the 1930s and have shown themselves to be an excellent alternative to stick building (i.e., conventional framing). SIPs are composed of some kind of foam (we used EPS, expanded polystyrene) sandwiched between two sheets of oriented strand board (OSB).
An experienced crew can put up a house very rapidly, and once it's up, you have walls, sheathing and insulation already in place. I hired a carpenter and two framers, and we were dried in in about a month. We also hired a tech. rep. for the first day to guide us through the process, and we had some volunteer helpers at times.
From an energy perspective, SIP houses are far superior to the standard stick built house. There are two features that result in vastly reduced air leakage through SIP walls. The first is the solid insulation. Air cannot move through solid foam.
The second feature is the sealing that keeps the air from entering at the seams and joints. As we assembled the walls and roof, we used Liquid Nails or spray foam at every joint and seam. We started by gluing the bottom plates to the floor with a continuous bead of Liquid Nails. The EPS at the edges of the SIPs was routed out so that it could slide over a piece of lumber that acted as a spline to join panels. The EPS was also routed out where they connected to the bottom and top plates. Before sliding the lumber into the panel, we sprayed generous amounts of foam into the SIP so that the joint would be airtight. 
I've done Blower Door tests on the house twice now, and the results show that the infiltration rate is practically nonexistent. The worst result I got was 846 cfm50. (cfm50 is the measure of how much air flows through the Blower Door fan when the house is depressurized to 50 Pascals.) From that number, the home energy rating software calculated the air changes per hour under natural conditions. (One air change per hour means that a volume of air equal to the volume of the house will be exchanged for outside air.) For winter, it's 0.08 ACHnat, and for summer it's 0.05 ACHnat. One other measure that's sometimes used is the ratio of the cfm50 to the square footage of the building envelope (sfbe). For this house, with 5904 sfbe, that value is 0.14. All of these numbers are very, very low. For example, a typical new house probably has about half an air change per hour, about 6 to 10 times greater than our house.
One consequence of a really tight house is that the indoor air quality can suffer. A lot of people think this means that you shouldn't make your house too tight. Really, though, you can never build a house too tight--but you can have a house that doesn't have enough ventilation. Because we knew the house would be tight, we installed a heat recovery ventilator. This piece of equipment brings fresh air in from outside and exhausts stale air from the house. The two airstreams don't mix, but they do cross paths and exchange heat. In winter, the cold air coming in gets heated up, and in summer the hot air coming in gets cooled off. In hindsight, I can see that I should have installed an Energy Recovery Ventilator (ERV), which does what the HRV does plus it exchanges moisture between the two airstreams.
Finally, the house is insulated better than a stick-built house because of the size of the SIPs. They're generally 4' wide, which means that you have 4' of continuous insulation. In a stick-built house, there's usually only 16" between studs. That means that a stick-built wall has three times as much area where wood, with its much lower R-value, provides the thermal barrier. In other words, the whole wall R-value is higher for a SIP house because there's more insulation and less wood.
SIP houses provide a lot of benefits, and if you're considering building with them, check out the Structural Insulated Panel Association or the book Building with Structural Insulated Panels by Michael Morley.