Glass Options

Associated products


Commercial use

Residential projects

Commercial projects


Exceptional Insulation

The key feature of a PassivHaus Window is the exceptionally high levels of thermal insulation that can be attained.

Using triple glazing as standard a PassivHaus Window can achieve Uw values of as little as 0.69 W/m2K to enable them to be used on PassivHaus projects as well as Eco housing design and Zero Carbon projects.

As well as incomparable thermal performance PassivHaus Windows have to have outstanding resistance to wind, water and drafts to create a complete seal against the elements.

Beautiful Design

PassivHaus Windows are created with a highly insulating composite frame to ensure the highest levels of thermal performance are achieved. With an aluminium external finish the composite windows are easy to maintain and the aluminium surface can be powder coated any colour to suit your design.

Internally you will see a beautiful timber frame, stained or painted to your design preference. Timber frames create a softer modern internal finish preferred by many and create a perfect edging to any window opening. 

A matching opening door design is available to create a full PassivHaus glazing design as well as an XL lift and slide door.

ASK US ABOUT OUR Passivhaus Windows



Keller Composite Passivhaus System

IQ offer the exceptional Keller Composite Passivhaus System to architects and designers looking for that extra level of thermal performance to their glazing.

Keller Composite Passivhaus System are the world’s leaders in the design of Passivhaus windows and doors, tested to rigours standards at the Rosenheim Institute in Germany to ensure their products thermal and weather resistance.

Their HF310 series of PassivHaus certified windows and doors are our window or choice for PassivHaus design thanks to its exceptional performance and clean design.

Don’t know what PassivHaus is? Click here to see our technical learning article.



All PassivHaus windows and doors are designed in inward opening configurations in order to create the impressive air tightness required for the Passivhaus standard. This has the additional benefit that all Keller Composite Passivhaus System window frames can be externally rendered, to completely hide these external frames within the external building render finish.

The Keller Composite Passivhaus System are available as tilt and turn windows, side hung windows, fixed windows or bottom hung windows.


As well as being Passivhaus Certified at IFT Rosenheim, the Keller Composite Passivhaus System windows have a battery of other exceptional test results allowing them to be used on some of the most exposed areas of the UK and beyond.

Thermal Performance Uw value 0.67 W/m2K

Air Permeability Class 4 to EN 12207

Water Resistance Class 9a to EN 12208

Resistance to Wind Load Class C5/B5 to EN 12210

Burglar Resistance RC2/RC2N to EN1627

Sound Insulation Rw 45dB


A range of Keller Composite Passivhaus System and doors are available to view at our architectural glazing showroom in Amersham. Keller Composite Passivhaus System doors and windows in a range of external finishes are available to inspect, touch and move.

Please contact us to make an appointment at the showroom with one of our expert technical sales team.

Commercial use

PassivHaus Windows for Commercial Projects


As performance criteria and environmental impact requirements for all project types increase the need for a higher performing window system is imperative.

PassivHaus Windows offer the highest levels of thermal, air and wind resistance available on the market today, whilst maintaining a modern window design.

Triple glazing is used as standard with a wide range of additional glass finishes or coatings able to be applied for various additional performance criteria.

The aluminium external frame creates a low maintenance external finish that can be used in even the most exposed locations throughout the UK with a marine grade coating.

Internal frames can be either timber or, in some instances, uPVC. Either frame option will maintain a PassivHaus standard as required which indicates an extremely low Uw value and high levels of resistance to wind rain and air permeability.

Building Regulations Part L2 governs the thermal performance requirements of non-domestic properties, which includes offices, schools and hospitals.

Thermal performance criteria differs depending on what type of work is being carried out but having well insulating windows is an important part of ensuring that a building has a low CO2 emissions and is a comfortable environment.


School Extension

A school extension in South Wales used Internorm HF 310 PassivHaus Windows and Doors throughout the design to ensure a high level of thermal performance and to achieve PassivHaus Certification.

The PassivHaus extension was part of a larger £3.8 million renovation to the school which looked to bring together both the infant and junior schools into one.

The other school buildings on site were renovated with various environmental defects being removed and the thermal efficiency of the other school buildings improved.

The impressive elliptical PassivHaus extension houses four new classrooms as well as various teaching support rooms and meeting facilities. It sits well between the existing school buildings and acts as a link between the independent areas.

By using Keller Composite Passivhaus System which achieve a Uw value of as little as 0.69 W/m2K the school design far surpasses the thermal performance requirements for school buildings as stated in Building Regulations part L2 and greatly reduces the schools impact on the environment.

One main advantage of PassivHaus design is the drastically reduced running costs of such buildings due to their high levels of thermal performance and ‘passive’ heating.

With school’s budgets being reduced it is a useful consideration for future school designs to reduce running costs.



Passiv Haus Windows and Doors Product Information