Passivhaus doors – the vital difference

GUEST BLOG: Malcolm Taylor, Product Manager at REHAU

In previous posts, I’ve talked a lot about the specification of windows to meet Passivhaus standards but of course, one of the most critical areas to be addressed in the design or specification of any Passivhaus project is the entrance door.

The market for composite doors is booming in the UK, particularly at the top end of the market where it’s quite common to see companies offering products with a D-value of 1.1W/m²K. 

However, this is a long way off the 0.8W/m²K required for Passivhaus compliance and there are relatively few mainstream manufacturers who can offer that – particularly since it applies to the complete door installation and not just the slab.

What makes a Passivhaus door different from a composite door goes far beyond a thicker and heavier thermally efficient slab – it’s also about thermally broken frames and thresholds and multiple lines of gaskets to protect against air leakage. 

Adding glazing of course places particular demands on the slab and even triple-glazing only normally limits the loss to around an overall door U-value (UD) of no more than 1.0W/m²K.  In fact, quadruple-glazing is typically required to reach an overall U-value (UD) of < 0.7 W/m²K.

If you compare the door on a Ford Fiesta to the door on a BMW 5 series, you’re probably getting close to the difference in weight and performance between a composite and a Passivhaus door but of course you’re also getting close to the difference in price since, like so much in the Passivhaus sector, these doors inevitably command a significant premium.

For that reason, REHAU has joined forces with German panel specialists Rodenberg to offer Passivhaus Institute certified doors which are closer to a mainstream option with frames in REHAU’s new AGILA door system.

Crucially, they don’t compromise on aesthetics and there are a whole range of contemporary panel options available to suit different styles of property.  See www.REHAU.uk/Passivhaus-Door for more details.  

Don’t forget, the deadline to enter this year’s Passivhaus Awards is Monday, 9^th May so if you’ve been intending to enter a project but haven’t got round to it, now’s the time to do it.