Putting Passivhaus design to the test

Using EcoClear sealed units in high performance triple glazed windows, H Jarvis has helped energy efficiency researchers at Nottingham University demonstrate how Passivhaus design can cut energy usage in homes by 72%.

The unique real-life test, aimed at demonstrating the difference in energy use between a property built to 2006 Building Regs and today’s Passivhaus standard, was completed with the technical and manufacturing support of GLASSOLUTIONS Solaglas and specialist newbuild fabricator and installer H Jarvis.

Featuring as part of the UK Passivhaus Conference 2012 held recently at Nottingham University, two identical-looking timber clad student bedroom pods were built and these were ‘lived in’ by student volunteers overnight so energy use could be carefully monitored.

The difference between the two pods came in the thermal performance of the building or ‘pod’ fabric. Casement windows fabricated by H Jarvis using EcoClear sealed units from GLASSOLUTIONS Solaglas were fitted, providing a 1.6 W/m2K whole window U-value in the 2006 spec pod and just 0.8 W/m2K in the Passivhaus pod.

The results of this snapshot study revealed that the student living overnight in the Passivhaus pod used just 28% of that used by the student occupying the Part L 2006 pod in the same period.

H Jarvis MD Dave Glendinning said: “We’ve been manufacturing and installing PVC-U windows for the newbuild and refurb markets with a 0.8 U-value windows for more than five years now so we know exactly how effective they are in driving up energy efficiency in our homes. Despite the genuine demand in the market for low energy solutions like our 0.8 windows and doors, independent testing such as this latest project by Nottingham University plays a vital role in encouraging even wider acceptance.”

Mike Butterick, marketing director at GLASSOLUTIONS Solaglas said: “The results of the Nottingham University study confirm our view that triple glazing used with a highly insulated building envelope can help save pounds on household energy bills.

“Current Building Regs mean a double glazed low-e softcoat sealed unit will suffice by delivering a whole window U-value as low as 1.2 W/m2K using the most advanced PVC-U frames. However, we have the technology today to deliver 0.8 performance for those looking to make the step up. This is a particularly strong proposition for companies like H Jarvis specialising in the newbuild market who can accommodate the requirements for Code for Sustainable Homes levels 5 and 6 developments.”

GLASSOLUTIONS Solaglas is one of the UK’s largest manufacturers of double and triple glazed units. Using the SGG PLANITHERM family of low-e softcoat products, its EcoClear branded sealed units have provided a low U-value solution for fabricators using all types of system for over 10 years.