Clearview Midlands March 2014 - Issue 148 | Page 32
doors&windows
MEETING THE CHALLENGES
Do U-Value DSERs?
Expert guidance is always welcome: in this article,
Mark Barsby The VEKA UK Group’s Head of
Technical, explains what you need to know on what
is undoubtedly a confusing and complex issue.
The expected changes to
Building Regulations Approved
Document L in England (which
set minimum requirements
for thermal performance of
windows and doors) - after
much anticipation, promises of
release dates which came and
went, and one false dawn after
another - were finally published
last November.
Apologies for the history
lesson, but for those who have
more exciting things to do with
their lives than I do: Approved
Document L has been split into
four sections covering the various
types of new/existing buildings
both domestic and non-domestic
for a while now. Unlike previous
amendments to Document
L, this time around only two
of the sections appeared to be
updated, which both covered
new buildings. We concluded,
therefore, that come April this
year when any changes came into
effect, for most of the window
and door industry no changes
were required in performance for
replacement windows and doors
from the current requirements.
A re-cap for those who haven’t
got this imprinted in their brain:
for windows this is a minimum
Window Energy Rating of Band
C or Value of 1.6 W/m2k; and
for doors a minimum U-Value of
1.8 W/m2k.
While an Energy Rating Scheme
(DSER) exists for external
32
MAR 2014
doors (for those of unsure of the
acronym it stands for DOOR
SET ENERGY RATING) it
is not currently included as
a method of compliance in
Building Regs. It is a purely
voluntary scheme.
The rumour mill had been
circulating for a while that DSERs
may be included in the amended
Document L, but when the two
sections dealing with existing
buildings were not updated and
published it appeared that the
rumours were unfounded. Or so
we thought! It wasn’t until you
read the small print at the bottom
of the page on the Planning Portal
(http://www.planningportal.
gov.uk/buildingregulations/
approveddocuments/partl/
changes that there was an
additional document titled
2013 Amendments to Approved
Documents L1B and L2B 2010
Editions. Buried in the text
somewhere at the bottom of page
5 in table 1, it now includes the
alternative of being able to certify
a door for Building Regulations
with a DSER of Band E or
better.
So there we have it! From April
this year, you will be able to
certify your External Doorsets
with a DSER as an alternative to
a U-Value of 1.8 W/m2k.
So what will that mean for the
industry?
While I don’t own a crystal
ball, we can look back at the
evolution of the Window Energy
Rating Scheme for some clues.
WERs were included in Building
Regs as an alternative method
of compliance to U-Values back
in 2006. Before this, there was
a great deal of interest in the
WER scheme, but it was seen
as a differentiator and a route
to market used by a relatively
small number of fabricators and
installers. While the inclusion
of WERs in Building Regs was
not particularly smooth and
created some animosity at the
time, today they are used as both
a compliance and selling tool by
the majority of fabricators and
installers.
We are comfortable with
WERs and are able to use the
recognisable label as a method to
clearly demonstrate the thermal
performance of our window to
customers and consumers.
At The VEKA UK Group, to
this point, we would readily
admit that whilst the DSER
Scheme has been around for a
while, there has been little interest
in it and from the few enquiries
that we have had, most do not
lead to certification. However,
if we look back to when WERs
were first included in Building
Regulations... I think we can
expect more interest and increase
in demand, particularly as
awareness begins to circulate the
industry that DSERs are now
included in Document L.
However, there will be challenges
and education needed. DSERs
for entrance doors cannot be
presented or sold in the same
way as WERs, as solar gain is not
included in the calculation. The
Minimum WER is a Band ‘C’ and
the minimum DSER is a band ‘E’
and if you glaze your windows and
doors with the same glass sealed
unit, they will not achieve the
same result. How will we explain
that to our customers - and present
a coherent sales pitch?
Just to make things more
complicated - DSER