Extensive experience with Passive House
We have experience of various building types; domestic,
residential and refurbishments, all to Passive House standard. You
can get inspired and read more about some of our cutting-edge
projects on the menu on the left.
Passive House solutions with Rationel Windows
We have extensive experience of Passive House Projects, and can
provide specialised technical assistance and advice to support your
organization from conception through to the installation of our
products, helping you meet your design brief.
We can also advise on how to optimise the window design and
glass solutions for different elevations. To give you the best
results we offer to fine tune the window part of the PHPP
calculation - after walls, floors, roofs and technical data
for heating/ventilation have been entered into the PHPP.
The window guidelines for Passive House are guidelines only,
while the criteria for heating demand (15 kWh/m2/year),
air tightness (0.6-1) and the primary energy demand (120
kWh/m2/year) are mandatory.
We have optimised our windows according to energy balance;
this typically results in a higher heat gain then heat loss
through the windows. This enables you to utilize the free solar
heat and thereby dramatically reduce your heating demand.
Be aware that using windows with the lowest Uw-value does
not necessarily result in the best energy performance for the
building as a whole.
Our experience is that 50% of the full heating demand can be
covered by solar heat gain though the windows.
To achieve the best results we recommend that the windows are
optimised according to orientation and shading conditions.
South-facing windows have the greatest potential for heat
contribution, followed by west and east. North-facing windows
will contribute with daylight, but are not thermally cost
Installation details are often overlooked but in our experience
it is important to understand that a lot of heat can be lost here
(linear transmission loss - psi-value), if this detail is not
developed in conjunction with the overall building design. A
well-designed installation detail can typically cut down 0.5-4
kWh/m2/year of the heating demand - a significant
proportion of the total allowance of 15 kWh/m2/year (up
We also have drawings of various installation details suitable
for Passive House with corresponding psi-values. However as these
vary we would recommend that the best solution is to have the exact
psi-value calculated on the project-specific installation
If an exact calculation isn't made then the final
PHPP calculation will be defaulted into the conservative
psi-value of 0.04 W/m K.