I seriously suggest you reconsider and or consult an architect who will advise you on the likely heat losses you will suffer.
Roof lantern heat loss.
Modern glazing has seen radical improvements and started to shake this historic view which is also the case with the roof lantern.
Heat loss of course incorporating a roof lantern to your extension will result in more heat loss than just a flat roof the same as putting windows in a room does.
Without a roof lantern blind you are very likely to experience the following.
The aluminium frame is designed to be as energy efficient as possible with an insulating t bar and thermally broken eaves beam.
This isn t the case with the roof lanterns from sheerwater glass.
Convection the draft loop.
Heat loss in the winter historically glazed extensions such as conservatories have gained the reputation of being too hot in the summer and too cold in the winter.
Loss of heat through warm room air reaching the glass cooling then cool air falling back into the room for you to have to re heat air leakage heat lost through cracks in the frame or from ill fitting glass.
If you re thinking of having 4m bifolds plus a roof lantern your kitchen will be so cold you could never use it.
Well the principle of rooflight design means that a rooflight can potentially lose 35 to 45 per cent more heat during cold weather spells than a similar window installed on the side of a house.