BWF members such as yourselves frequently use our Member and Technical Helplines for assistance on a wide range of Employment, Health and Safety, Pay and Technical issues. We’re putting up a frequently asked question every Tuesday in order to help members and illustrate the type of advice we are able to provide. If you have any questions that you would like to see featured, we would be happy to assist. This question and many others like it can be found in our Question Centre. If you want further advice on any of the issues, don’t hesitate to ring the helpline or browse our extensive publications library, which includes our Fact Cards and guidance on installing timber windows. This week: Will all replacement windows have to be C-Rated by October 2010? We’ve had a sudden influx of calls in recent days from members worried that the Building Regulations are set to change later this year to require that all replacement windows must have a BFRC Window Energy Ratings of C or better. The callers, most of whom are from smaller specialist manufacturers who make bespoke windows for individual projects, are deeply concerned that the cost of obtaining energy ratings for windows whose design and manufacture vary from project to project will be more than their business can bear. The calls have been prompted by the marketing of seminars to explain the forthcoming changes to Part L and offer help in achieving window energy ratings. These draw on an expectation that the proposals in the Government’s consultation on the revision of Part L will be implemented. These included amending the guidance in the Approved Document to require the minimum energy efficiency of a window to be a BFRC C Window Energy Rating; but also said that an equivalent U-value would be acceptable. In our response to the consultation, the BWF said that it was essential that U-values were retained in some form precisely because of the difficulties moving to a requirement for Window Energy Rating would cause to small specialist wood window manufacturers. Also, depending on what decision is made, in order to have energy ratings, you will also need to have air tests carried out (to define air leakage) and that centre pane values may not necessarily be allowed. As a rule of thumb, you can usually expect most of what is in a consultation proposal to make it into the final agreed policy. But questions always emerge, and some elements will change. The honest answer is we don’t know if window energy rating will become the preferred method of showing compliance and won’t until the new Part L is published. Nor does anyone else. It’s expected in April, to be implemented in October. But there is an outside chance that plans for publication might get caught up in the run-up to the General Election and be delayed. Once it is published, the BWF will explain the changes and provide guidance on how to comply. We’ll also put together a Total Support Service package to help. If you make windows, you need to be aware that Part L is going to change and the energy efficiency standards are almost certainly going to increase. It’s likely that proving the energy efficiency of your windows will become more rigorous. But nothing has been confirmed yet. A meeting held recently discussed how a FENSA inspector could easily determine whether or not the thermal performance of an installed window would comply with the new Part L requirements. It was agreed that the FENSA board would be asked to consider the following methods:
1. Energy Ratings – BFRC or equivalent
2. U-Values:
a) Taken from the CE Mark
b) Determined by a complex calculation or simulation
c) Taken from tabulated values