INDUSTRYNEWS
The Vexed Issue of the Trickle Vent
As consultations around the Government ’ s new Future Buildings Standard close , VEKA Plc ’ s Technical Director , Paul Kennington , applauds plans to make homes more energy efficient but questions whether the vexed issue of ventilation has been solved .
» THE RESULTS ARE IN ; OVER THE last two years , the Government has been running consultations that first covered domestic new build through the Future Homes Standard , with their responses now published , and a second round of discussions covering Future Building Standards . The responses from industry are now being considered , with new legislation expected by June 2022 .
The changes are designed to improve the energy performance of new homes , as part of the UK ’ s commitment to achieve net zero emissions by 2050 . Existing homes will also be subject to the new higher standards , with more energy efficient replacements and repairs designed to make homes warmer and reduce bills .
Overall , the likely changes will pose few problems and VEKA is already set up to achieve any new , improved U values . The big issue , however , is likely to be ventilation , and the continuing saga of the trickle vent .
Prior to the consultations , we spent a lot of time speaking to our customers and explaining that while many of the suggested changes were improvements , the issue of trickle vents simply hasn ’ t been thought through .
The problem is that as homes have become better insulated , they have also become less ventilated . Drafts have become a thing of the past , cutting off the natural flow of air that once moved on odours , pollutants and condensation .
It was an issue once solved by leaving a window open , something people are now less likely to do for security reasons . As a result , trickle vents have been seen as the answer . Apart from the fact that aesthetically they ’ re not great , they also mean that after decades of working to improve the U value of windows , we are now being asked to install them with a hole in ; not great when you ’ re trying to make homes more energy efficient .
The thermal properties of windows are calculated as a whole unit , without taking into account the effects of trickle ventilators . So , for example , while a window can claim a value of 1.4 , its performance is actually below this level because of the vent . Although new windows will have better performance when it comes to issues such as air leakage , the improvement over an existing window may only be marginal because of the ventilator .
Trickle vents are also most needed when people are in the house , yet occupancy tends to be highest at night when , for a large period of time , curtains are drawn , cancelling out any benefit the vents will bring .
Many homeowners also install new windows to help cut out noise , yet trickle vents can actually make the noise inside a room more intense , leading to disappointed customers and frustrated installers . Schemes highlighting the acoustic performance of windows don ’ t account for trickle ventilators , so as with thermal calculations , the actual acoustic performance will be reduced .
In new build homes , there are already requirements to provide a certain amount of ventilation , and the easiest and cheapest way to do this is through a vent in a window . But the legislation could now move on to include replacement windows , too . Currently , if an existing window doesn ’ t have ventilation already , then while it is considered good
practice to include it in any replacement , it isn ’ t mandatory . However , Part F of the new proposal suggests that if replacing windows is likely to make the building less compliant with ventilation requirements than before the work was carried out , then additional ventilation should be provided .
There are some anomalies in the proposals , too . For instance if you refurbish a bathroom or kitchen , and it hasn ’ t got extraction ventilation , then you don ’ t have to include it in the refit . Yet these are the two areas in a home that produce the most pollutants and odours .
There are also questions around increased costs , with the government suggesting that including trickle vents as standard on a new window would add just £ 2 , yet our own conservative estimate puts the true cost at closer to £ 25 .
I truly believe that trickle vents pose more of a headache to the fenestration industry than any other single issue at the moment , from aesthetics to cost , customer satisfaction to manufacturing modifications .
www . veka . co . uk
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