The Part L Building Regulations changes do affect you…

…..If you own a property these substantial changes affect what you can now legally do, when extending or replacing any window or door in your property. The Government is in effect â€Ŕmaking you” install even more thermally efficient windows from 1st October 2010 to help it meet its carbon emission reduction targets and save energy. It is UK property owners that will have to fork out for these higher performing products without any form of Government subsidy.

These changes announced the Government’s approved document L1B entitled â€ŔConservation of fuel and power in existing dwellings” require property owners to install even higher performing energy saving products than currently required if they a) replace their existing windows or b) have an extension or c) build a new house etc.

From 1st October 2010 it will only be legal for window companies to take orders for windows with a Window Energy Rating (WER) of band C or above, or a combined U Value of 1.6 W/m2K for installation into existing dwellings. Likewise, all doors ordered on or after 1st October 2010 will have to have a maximum U value of 1.8 W/m2K (U values are a universal method of measuring thermal insulation). All windows and doors ordered on or before 30th September 2010 must be installed before 6th April 2011.

Any products installed on or after 1st October 2010 will have to comply with the new stricter Building Regulations. Consequently, property owners will only receive a FENSA certificate if they install products that have been approved and certified by the BFRC as attaining the new higher energy ratings that will soon be required by law if any window or door is replaced.

“The major changes in Building Regulations have significant practical, legal and cost implications for property owners, developers and the double glazing industry,” says Mark Austin, Marketing Director of the Hazlemere Group. “So, substantial are the changes, they are something every property owner really needs to be aware of, as they do have massive implications if anyone wants to install windows and doors to match the ones already in their property, given the vast majority of double glazing products currently in the UK market will legally become obsolete after 30th September 2010.”

“The best performing energy rated windows have a higher specification, so by definition cost more, so in effect, whilst property owners will benefit from energy savings (assuming the rest of the property is properly insulated!), after 30th September 2010 they will be legally obligated to order and install higher performing thermally efficient products. Consequently, property owners will need to order before the 30th September deadline if they want to install â€Ŕmatching” windows and doors that only meet the current Building Regulations.”

For further information on Part L and energy saving windows, doors and conservatories contact a Hazlemere expert consultant for a no obligation chat on FREEPHONE 08000 825825 or visit


Our showrooms are our shop windows and we have invested heavily to create extensive displays that best showcase our large range of windows, doors and living spaces. You will receive a warm welcome, plus a proper coffee, and the choice to browse at your leisure without interruption.


Want to speak with an Advisor? Give us a call on 08000 825 825

Our friendly team will be pleased to help with any questions you may have.

Back To Our Blog