Structural Insulated Panels and SAPs
Structural Insulated Panels come into their own when it comes to complying with the increasingly stringent Part L of the Building Regulations and in particular the SAP 2010. The SAP rating is a measure of the overall energy efficiency of a dwelling and takes into account a number of factors including the efficiency of the heating system, the u-values of all of the building elements and any renewable technologies that might be being used. Several of these areas are met and enhanced by using Sips Eco Panels. A few of the benefits of using structural insulated panels for SAPs are listed below:
Excellent U-values. By specifying Sips Eco Panels you will achieve low u-values (as low as 0.14) on both your walls and roof helping you to heat your property more efficiently.
High levels of air-tightness. Due to the inherently air-tight way that SIP frames are constructed, structural insulated panel builds typically have lower air pressure results, meaning easier SAPs. A typical Sips Eco Panel house will achieve between 2 and 4 acph @ 50pa and can achieve even lower.
Less cold-bridging. Whereas with timber frame there is a repeating cold bridge in the timber studs at 600mm centres, due to the unique stressed-skin action of a structural insulated panel, SIPs do not have this issue. There is therefore minimal cold bridging in the walls, making for better SAP results and easier compliance with Part L.
Lower thermal mass. Contrary to popular belief, SAP 2010 generally looks on lower thermal mass more favourably than higher thermal mass. Thermal mass is the ability of a substance to absorb and store heat. The higher the thermal mass, the slower it responds to changes in atmospheric temperature. SAP 2010 takes the view that if something responds quicker to heat changes, the user can turn off the heating / cooling quicker and therefore use less energy. Structural insulated panel structures have lower thermal mass than some other forms of construction.
These points are re-iterated by Jon Ponting of Energist UK who are SAP rating and Code for Sustainable Homes specialists. Jon said:
"Structural insulated panels can perform favourably in the latest SAP Calculations to show compliance with Part L, provided they are installed and used correctly.
They can help to provide very low air test results, they have low thermal mass and can also benefit from low levels of thermal bridging. The higher specification SIPs panels are fitted with additional levels of insulation, so lower U-Values can also be taken as a benefit when building to the new Part L.
Air flow and ventilation rates are a key element to showing compliance with the latest SAP methodology, so any material or device which can help a developer do well with the above four points should be strongly considered for future developments."