Case for future-proof VIPs heats up

By Promat 03/09/2019

Promat SLIMVAC vacuum ultra-lightweight insulated panel
Promat SLIMVAC vacuum ultra-lightweight insulated panel

With louder calls for more immediate action to mitigate the effects of climate change, and the next review of Part L to be announced soon, is now is the time to take a fresh look at how vacuum insulated panels (VIPs) can upgrade your next building envelope project?

According to the UK Green Building Council (UKGBC), the built environment contributes around 40% of the UK’s total carbon footprint, much of which can be attributed to the energy used to heat properties. Whilst greener, renewable based heating systems will help reduce this, ultimately the building envelope must be insulated to the optimum level too.

The ‘fabric first’ message is by no means new, but with the mounting evidence on how climate change is affecting our planet, combined with the international commitments to CO2 reductions made by the government, it is only going to grow in importance. Without a focus on designing and buildings to keep warmth contained, rather than losing it through poorly insulated roofs, floors and walls, it could be difficult for the UK to meet its legally binding target of an 80% reduction in carbon by 2050.

Vacuum insulated panel (VIP) technology has already found a niche in the building envelope sector, particularly for refurbishment projects where space constraints make more bulky, thicker insulation products unsuitable. But the technology, which was pioneered by Promat more than a decade ago, has enormous scope to be used in all kinds of new build and refurbishment projects, not as an alternative, but as a default way to achieve a high level of thermal insulation whilst at the same time maximising interior space.

The perception that VIPs are too expensive to be viable is outdated and does not consider the long term view. The performance improvements that VIPs can deliver, combined with allowing for increased usable, lettable floor space inside properties thanks to thinner wall constructions, could result in significantly lower whole life costs with a reduced carbon footprint. Hence, over the lifespan of a property, VIPs could help landlords, housebuilders and owners derive much greater value.

How vacuum insulation panels work
Unlike conventional insulation, vacuum insulated panels are specially manufactured using a microporous core covered in an impermeable outer envelope, which is heat sealed under a vacuum. As a result, they achieve the same performance level as a conventional structural insulation such as PIR, EPS or XPS insulation boards, but with a much reduced thickness. In fact, one estimate is that a U-value of 0.3W/m2k delivered by a 100mm thick panel of expanded polystyrene (EPS) insulation could be achieved with just a 30mm VIP.

Heat transfers by three methods. Convection and conduction both need air molecules to do so, whereas the third method – radiation, which is the type of heat we get from the sun – does not. The gas-tight outer envelope of the VIP is sealed to prevent outside gases from entering the panel, which minimises the transfer of heat by convection and conduction.

All vacuum insulation panels are gas-tight and custom manufactured to order – so they cannot be cut to size on site. Doing so would be detrimental to the panel’s thermal performance. But, the panels are supplied with special jointing tape, floor covers and top covers to ensure the most effective thermal barrier can be achieved on site with ease. Promat’s SLIMVAC® panels are also moisture resistant up to 60% and contain no harmful materials to allow for easy post-use recycling.

Increasing usage of VIPs
Greater understanding of heat loss in homes and buildings has expanded the scope of VIPs to create superior building envelopes with greater energy efficiency. Roofs, floors and walls are, of course, the key areas in which VIPs can deliver improvements, but there are other building aspects that will benefit too.

With roofs typically accounting for 30% of energy loss, using VIPs within the ceiling construction beneath a pitched roof is an ideal way to provide a stylish and energy-saving top floor room without the need for thick insulation layers under the roof. This will maximise the room height to give it a roomier feel.

Flat roofs, terraces and balconies are also culprits for excessive heat loss, so utilising VIPs here rather than conventional insulation will have a positive impact. In the case of external terraces, using VIPs will eliminate the need and cost to raise internal floors to match, which could actually make VIPs a more cost-effective option. Heat loss caused by thermal bridges can also have far-reaching consequences, including moisture and mould issues that lead to health problems. Thermal bridges can be subtly neutralised using VIPs leaving an unblemished, comfortable and healthy interior.

With public pressure demanding more urgent action to mitigate the effects of climate change, the energy efficiency of UK properties can be vastly improved with ease right now. The ‘low hanging fruit’ for architects and contractors is to deploy proven technology that we know will help insulate properties to a superior standard and there is no better example of this kind of solution than VIPs.

This article was published exclusively in August's edition of the Roofing, Cladding and Insulation (RCI) magazine.