Achieving Fabric Energy Efficiency Standards

Building to 2013 standards, Code level 4 or 5, or looking
towards 2016 and Zero Carbon, CavityTherm in a traditional
brick wall with a reasonable cavity width will get you there!

Achieved U-values

ElementU-values (W/m²k)
Thermal BridgingY=0.05
Air Permeability5m³/hr/m²

FEES Targets (Conducted in a range of dwelling types)

U-valueUnit (W/m²k)
Walls0.15 - 0.18 W/m²K
Roofs0.13 W/m²K
Floors0.13 - 0.15 W/m²K
Windows1.2 - 1.4 W/m²K
Doors1.0 - 1.4 W/m²K
Thermal Bridging0.04 - 0.07 W/m²K
Air Permeability5.0 - 5.2 m³/hr/m²@50Pa

CavityTherm is not unique amongst Xtratherm products
in delivering thermal performance beyond simple U-values.

The Xtratherm product range that includes walls, floor and roof products deliver not only the U-value requirements
for Passive standards, but are also critical in the detailing required to reduce thermal bridging heat loss.

Floors - 0.12 W/m²K
Walls - 0.15 W/m²K
Roof - 0.15 W/m²K

Below we show a self-build project (simplified to allow junctions to be identified).
Let’s look at how the specification needs to be improved to compensate for poor detailing.

y = 0.03 (Thermally Modelled Junctions)
The equivalent of an open ‘Window’ 1.25m x 1.25m (1.56m²) opening.
y = 0.08 (Accredited Details)
The equivalent of an open ‘Patio
Door’ 2.1m x 1.8m (3.78m2)
y = 0.15 (SAP Default)
The equivalent of an open ‘Garage
Door’ 2.1m x 3.3m (6.93m2) opening.
Y-value 0.03 using Xtratherm products with approved PSI values - within Accredited details and calculated.Y-value of 0.08 based on the use of Accredited Details but not calculated by the Assessor.No particular detailing specified or witnessed
Default value
Details UsedAccredited DetailsAccredited DetailsUnspecified / or Witnessed Details

Do you have any questions?

Tale to the team who can help you with your project

Our Technical Team provides technical services throughout our customer bases in Ireland & UK. Their experience and expertise has been built through our engagement and participation with the Irish construction industry for over 30 years.

Certified Technical Knowledge.

Solutions you can trust.

Call The Technical Team:
Tel +44 (0) 371 222 1055
Tel +353 (0) 46 906 6050

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Accredited Details for Construction (ACDs).

BIM Files

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