3 or 5 Chamber upvc Profile for Door

[billm]

I am finalising the spec for a replacement upvc back door that is North facing.

The spec is as follows :

White upvc door with glazed upper, single panel lower, 50/50 design
3 hinges
Frame: 70mm profile with a 52mm bottom rail
Internal beading
Low eGlass, Argon filled 4-20-4 sealed unit with warm edge spacers

The U value of a upvc frame is higher than the glass so I would like that to be efficient where possible.

One supplier is quoting Rehau Total 70 Chamfered (5 chamber) while another is quoting Spectus Elite 70 (# chambers unknown) and I am waiting for a quote from 7-Day Windows so as yet I am not sure what profile/chambers they use.

I believe that a 5 chamber profile is thermally more efficient than a 3 chamber profile, but by how much ? and does it make much difference vs any additional cost ?

thanks

 

[Mw Roofline]

Hi mate if u added up all the surface area of the frame it's not worth worrying about it.