Convention in Focus: Glazing Age
Convention 3.12 is one which often causes issues for DEAs, especially since the latest review of
the wording (v.9.0) seemed to make the whole Convention contradictory. The following should
help assessors with correctly applying this Convention.
Ignore the homeowner and your opinion
It might seem a harsh statement, but purpose of the Conventions is to ensure that all energy
assessors can make the same assumption given the same circumstances and evidence.
Assessors would not take the word of the homeowner in relation to levels of insulation without
documentary evidence, and the same should be true for glazing. The same is true for an
assessor’s own beliefs about the glazing – unless it can be backed up by appropriate evidence,
the worst case scenario from the Convention shall be use.
Assessors should also be reminded that the specific requirement is the year of manufacture of
the glazing units, not their installation. Simply because the units may have been installed in
2005 is not a reason to select ‘post-2002’ glazing.
FENSA Certificates
These certificates confirm that all replacement glazed windows and/or doors were produced
after 1st April 2002. Not many homeowners tend to retain this documentation, but it is
acceptable to provide details from the FENSA website which demonstrates this.
By visiting http://www.fensa.org.uk/fensa-certificate assessors can go through the process to
re-order a certificate. The basic details can be seen and saved prior to any payment
requirement, and this would be perfectly acceptable for auditing purposes.
Scrolling down the page on the FENSA
website will show the following input
section.
Simply input the postcode and house
number of the property being assessed,
and the website will provide details of
previous glazing installations within the
defined period.
The extracted information displays the
address, the date of issue of the certificate,
and the numbers of units replaced. It might
be possible that only sum of the windows
were replaced to a newer standard. The
predominant view should apply in this
case, most probably ‘Unknown’ glazing age.
How should Convention 3.12 be interpreted
All DEAs must have undertaken the learning module when the latest version of the Conventions
was released, and this would have outlined how the Convention should have been followed,
specifically with post-2002 built housing using this age to default the glazing age.
The best way to interpret the Convention would be:
Choose unknown date if there is no evidence of the date.
Multiple glazed units can be dated via the following methods;
a) The manufacturing date on the spacer bar, or possibly on the frame;
b) There is documentary evidence confirming the date of installation of the
window e.g. FENSA / CERTASS / Building Control certificate or manufacturers
guarantee;
c) Property build date if after the following trigger dates: Post 2002(E&W),
2003(Scotland) or 2006(NI) where applicable.
If none of the above applies choose ‘unknown’.
It is highly likely that this wording will be incorporated into the next release of the RdSAP
Conventions so assessors should take this on board now to aid with the quality and consistency
of their reports
