Since 1 July 2013 every window covered by EN 14351-1 must carry the CE mark and a declaration of performance, or DoP. This follows from Regulation 305/2011. The manufacturer who signs it takes responsibility for the product matching what was declared. A leaflet commits to nothing. A declaration does.
What is in the declaration
The intended use, and the list of essential characteristics from the standard:
- thermal transmittance Uw,
- air permeability class to EN 12207,
- watertightness to EN 12208,
- resistance to wind load to EN 12210,
- sound insulation Rw with the C and Ctr corrections,
- glass properties, i.e. g and LT.
For some characteristics the manufacturer may enter NPD — "no performance determined". Worth noticing.
How to use it
Ask for the declaration for the configuration offered, not for the system. Uw depends on the glass unit, spacer and size, so a declaration for a different unit proves nothing.
Check that the Uw of the whole window is given, not the Ug of the glass alone. Ug is always lower, and some sellers quote only that.
If two quotes have the same profile and a similar price, compare the air permeability and watertightness classes. That is where you often see the difference in hardware and gaskets that a photo does not show.
On delivery
The declaration is useful once more. The building inspector has the right to ask for it, and without it the window formally should not be placed on the market. Every delivery of ours comes with the declaration and CE documentation for each product type — keep them with the invoice.
Want to compare your quote with ours? Send it over or build the same window in the configurator — we reply within 48 hours, with a declaration for the specific configuration on request.