Over the last few years, there has been an increase in pressure for far more stringent energy efficient products, driven by current and future legislative requirements combined with homeowner demands. Selecta Systems Technical Manager, Cliff Prosser, has been looking through the Selecta archives and articles that were written back in 2017, with concerns and questions raised that still seem pertinent to the current plight that we find ourselves in today.

I was recently looking through the technical archives and I found two particular energy efficiency related articles written and published by the previous technical team, that really caught my attention. It certainly seems like we were looking in to a crystal ball back then! This is particularly interesting on how we spoke about energy efficiency and the route the industry was deemed to be undertaking. What seems significant is that here we are, some 6 years later, with the very same concerns and questions still being raised!

We had acknowledged that the technical performance and specification of window and door systems had improved dramatically over the years, as window and door solutions evolved. It also identified that consumer demand within the replacement market would not only be for energy efficient products, but for more cost effective solutions in being able to deliver those savings with a guaranteed financial return on their investment.

The articles spoke of “sales and marketing campaigns driving fabricators and consumers as to requiring A++ ratings and triple glazed windows and doors to improve the thermal efficiency of properties and reduce energy bills”. This is no different to todays push with U values, Document L and the Future Homes Standard. But more importantly the article spoke of how meeting these rigid targets may present companies with the difficulty of being able to provide cost effective solutions for all.

It points to whether the cost and impact of improving the thermal efficiency of windows and doors may outweigh the overall savings. For instance, the end consumer may never see any return on their added investment when it comes to energy bill savings. Then there’s a business’s extra production and manufacturing costs to produce a product, which could possibly end up increasing its carbon footprint. This could certainly be the case for laminated glass production. Solve one problem, create another! Pretty much a similar scenario with electric cars. Ideology is great, but cost effectiveness, poor infrastructure, non-recyclability of batteries, impact of mining etc. all have detrimental effects in other areas, but hey, “I’m saving the planet by driving an electric car!”

It was interesting that the 2017 article touched on the possibility of ”over engineering a product just for the sake of achieving a higher rating”. In the replacement market, is a 0.2 decrease in U value really going to improve the overall efficiency of a property? Referring back to the extra manufacturing requirements and costs to achieve such a decrease, which if we were to analyse, would possibly bring minimal to zero improvements to the overall efficiency of the property and or energy savings to the homeowner.

It should not simply be about trying to provide a window or door solution that achieves the lowest U value, but we should be giving greater prominence in the ‘cost effectiveness’ achievement factor to the extruder, fabricator, installer and more importantly, the consumer. Will a 0.2 or even a 0.4 U value decrease provide a large leap in potential energy savings to the end consumer and the thermal efficiency of the property in comparison to the added expense in achieving this?

The articles continued to query whether there “must be a ‘cut-off’ point where the ‘efficiency’ reaches a level that it could be detrimental to the building fabric and the whole cost against benefit of installing the windows or door is no longer pertinent”. I believe this is still relevant when you consider the conflicts relating to documents L and F and the stabilisation of temperature within a property. Another point to add, with it all based on simulation, there’s also no consideration in to the quality of fabrication or installation of the windows or doors, a completely different ball game altogether.

As a systems company at the top of the supply chain, everyone may benefit from a more pragmatic and realistic approach to U values. For instance, moving to a centre pane U value would be the more logical approach, with glass making up at least 85% of all windows and most doors.

It will be interesting to look back in another six years or so to see if any sensible progress has been made in answering these queries and whether common sense does prevail.