Bottom operated

GZL 1051 B / GLU 0051 B

GZL B: From xxxx €
GLU B: From xxxx €

Operated by an elegant handle at the bottom, this roof window is our recommended solution when placing the window in a high position, for instance because of a high knee wall. Ventilation is adjustable by click-open vent or handle lock position.

New: From 2018 all our roof windows, including the Standard range, are delivered with ThermoTechnology™ and our draught-protection gasket. Together, they make a unique insulation system for the ultimate energy-efficient shield against the cold and draughts.

Essential functionalities

  • Optimised 2-layer pane UW 1.3 W/m2K
  • Draught-protection gasket
  • All-year weather resistance
  • Fresh air even when locked
  • Easy cleaning position
  • Prepared for click-on blinds

Product details

  • 1
    All-year weather resistance 

    All-year weather resistance

    VELUX roof windows are tested to withstand the weather of any season, from rain and hail storms in the summer to snow and ice in the winter.
  • 2


    Our Standard windows all have ThermoTechnology™ fitted. This unique insulation system gives you an extra powerful and energy-efficient shield against the wind and cold air, keeping your home warm.
  • 3
    Fresh air even when locked

    Fresh air even when locked

    The 2-level ventilation system lets your home breathe, even when the window is closed. Click once or twice to adjust how much air you let in – and enjoy clean fresh air any time of day or night.
    The in-built air filter gives you a healthier living space by stopping dust and insects from entering your home. The filter is easy to vacuum clean.
  • 4
    Easy cleaning position

    Easy cleaning position

    To clean the outer pane, rotate the sash 180 degrees. The sash must be secured in position by sliding the barrel bolt into the bushing at the bottom of the side frame. Both hands are free to clean.  

  • 5
    Prepared for click-on blinds

    Prepared for click-on blinds

    Complete your VELUX roof window with a VELUX blind. All our roof windows come with pre-fitted mounting brackets for easy installation of all VELUX blinds. Blinds click in place instantly and precisely. We call it Pick&Click!™ VELUX blinds offer effective sun screening and heat protection to suit every need. Choose among exterior awning blinds or a range of interior blinds.
  • 6
    Internal finish

    Internal finish

    Pine finish roof windows are coated with a water-based clear lacquer that protects the wood against dirt and moisture.
    Maintenance-free roof windows feature a strong core of thermo-modified wood with a seamless waterproof polyurethane coating.
  • 7
    Care kits

    Care kits

    If you want to prolong the longevity of your VELUX roof window or simply give it a touch up, this is the place to look.  

    VELUX offers a range of products that will come in handy if you want to replace an air filter, repair a scratch, lubricate hinges, paint your window and give it a new and shiny lacquer.

  • 8


    VELUX offer you 10 years guarantee on windows, flashings and insulation panes.


VELUX Standard roof windows are available in various finishes and operation options. Click on the relevant section opposite for further information

  • Internal  finish
    Delivered in clear lacquer pine wood finish or white maintenance-free finish.
  • Exterior finish
    VELUX Standard roof windows come with grey aluminium exterior covers. 
  • Glazing performace
    Double glazing
  • Operation
    VELUX Standard bottom-operated roof window has an elegant and ergonomic zinc bottom handle for convenient operation when installing in high-knee walls.

Choose the right roof window type and installation height

Mostly we recommend to buy a top operated roof window. A roof window is ideally installed low (starting 90 cm from the floor) – this will lead to a great view to the surroundings and at the same time leave space to furnish below.

For professionals

Are you an installer, architect or a dealer – follow the below links to find more information about installation, drawings and technical details. If you are looking more tools and information - go to the professional section to find even more such as installation videos, architect cases, CE marking, how to become a VELUX certified installer

You might also be interested in...


Standard Plus