Although they have been around since the 1950s, structured insulated panels (SIPs) have only recently become a mainstream choice for new construction. They are a remarkably simple and straightforward idea: rigid foam insulation pre-sheathed and cut to standard or custom sizes.

While all SIP manufacturers produce standard-sized panels ranging from 4 feet by 8 feet to 8 feet by 24 feet, most companies will also take a building's blueprint and custom cut panels to fit the design. These custom panels have window and door spaces cut out and are delivered to a building site clearly numbered so that they can be assembled easily, much like super-sized IKEA furniture!

Structured insulated panels are more expensive than normal panels, but they have many advantages:

• SIPs are available in a variety of thicknesses, generally ranging from 2 to 12 inches thick, with increasing R-values as they get thicker.
• The panels are much more airtight than standard stud walls. A 4-inch-thick SIP has an R-value from 14 to 24 compared to a similar stud wall's rating of between 11 and 15 when filled with rock wool or fiberglass.
• SIPs have better R-values than even high-density fiberglass or wet-blown insulation.
• There is no insulation bridging loss with SIPs.
• Many SIP manufacturers provide the panels with drywall on the inside and/or siding on the outside, so wall construction becomes a simple matter of placing the panels and joining them together.
• Because SIPs are pre-fabricated, they reduce waste from cutting and trimming, as well as reducing construction time and labor costs on-site.
• Most SIPs are made of expanded or extruded polystyrene (EPS and XPS respectively) or polyurethane. The EPS option is usually cheaper and uses no HCFCs in its production, so is kinder to the environment compared to the other two.
• If you don't want to use an oil-based product in your SIPs, there are some companies (notably Agriboard) who make them out of compressed straw and hay.

With all those benefits, the real question is the extra cost: is it worth it?

Surprisingly, SIPs can actually work out cheaper than using standard panels. They do generally cost more as construction materials – from 10% less to 10% or 15% more than standard panels – but the fact that they are so easy to use often counters the extra raw material cost.

SIPs do not need to be cut on-site (especially if you get the custom-cut ones). There is minimal fixing required to get them into place. They are straight, true, and plumb (unlike standard 2x4s and 2x6s), so there's no loss from warped timber or time wasted hunting for a piece the right size. They also give better R-values, which means your home will need less heating and cooling every single day. It's almost a no-brainer when you consider the advantages – the investment will pay for itself quickly and constantly.

There are two caveats to this analysis, though:

1. You must make sure that the construction team is familiar and experienced with SIP installation. If they have never used the panels, you are less likely to profit