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Katzbeck MASSIVA

The heat insulation of a window depends on the material of the frame (the values indicated refer to spruce wood), on the glazing and the imperviousness. The parameter for the insulating characteristics of a window is the Uw-value. Heat insulation is better the lower the value is. The sound absorption of a window depends on the material of the frame, on the glazing and the permeability of the mortises. i.e. the tighter the window shuts the better its sealing value.

Variations in the technical light and radiation values are possible due to the manufacturing process and the chemical composition of glass.


Heat insulation and sound absorption values for windows depend on size and model. In adherence to current standards, all values indicated refer to single casement windows with the following dimension 1230 x 1480 mm and to the models described in the test certificates. Any deviating dimensions and models may result in other values.

Uw = calculated or tested heat insulation of the window (is indicated in Watts per square meter Kelvin = W/m²K)

Ug = heat insulation of the glazing

Uf = calculated or tested heat insulation of the frame (is indicated in Watts per square meter Kelvin = W/m²K)

Rw = soundproofing tested in laboratory (dB)

How we can help you with installation


It is essential to get the installation right in order to get the best energy performance from the windows, as well as ensuring that they operate correctly. We offer an expert architectural detailing service for window and door installations, this describes how to position and fit the window/door to achieve a thermal bridge free and airtight construction.

We can offer a UK based fitting or advisory service (depending on the project's size and location)


Taking delivery of your windows


Triple glazed windows are of course very heavy. The glazing in a typical unit (with 3 x 4mm glass) weighs 30kg/m², plus the weight of frame and fittings. Some products, such as sliding doors, are delivered in large units that cannot be dismantled on site: such units could weigh in excess of 600kg. A typical window will weigh between 50kg and 100kg. This means that, when unloading the windows, either fork lifts or spider cranes may be needed.

We are not able to accept liability for any damages during unloading nor it is not the responsibility of the driver to unload the windows.

Complete our downloadable Window Schedule and email, together with 1:100 elevations and 1:50 plans, to windows@phstore.co.uk. Technical details relating the various window ranges can be found in the technology brochure (see downloads tab) Once we have all the information needed, we will normally send you a quote, which will include delivery to your site, within 10 working days.


Placing your order and payment


Once order details have been finalised and signed off, a down payment of 50% is required with the order, the balance payable prior to delivery.

Delivery time from approx 6 weeks from confirmation of order for windows and 8 weeks for doors



All wood window available as MASSIVA or MASSIVApassiv


KATZBECK MASSIVA high performance all wood windows: suitable for Passivhaus, zero carbon, ultra-low energy buildings in contemporary or conservation settings. Massiva and Massiva Passiv are all wood construction (except for narrow aluminium capping on horizontal cill sections). KATZBECK sources all its timber from sustainable, FSC certified forests and uses environmentally friendly finishes.

Both ranges are available with additional muntins/glazing bars and mouldings making them ideal for retro-fitting or creating new buildings in traditional styles and conservation settings but with state-of-the-art energy efficiency.

With Uw from 0.75 W/m²K for the MASSIVA and from 0.71 W/m²K for the MASSIVApassiv.

Reasons to buy KATZBECK triple glazed windows


  • Greatly improved comfort and better use of internal space
  • No down drafts or 'cold radiant'
  • Excellent energy performance - glazing, frames and spacers
  • Durable - excellent build quality
  • Styles that meet requirements of conservation areas
  • Very competitively priced


  • Brand: Katzbeck
  • Product Code: KWM
  • Availability: Contact us for a QUOTE