Extensions with flat roofs and lanterns
Many Clutton extensions are low and wide, with a flat roof and one broad pane of glass overhead. The room looks lovely when the sun is soft and feels punishing when it is not. If your rooflight is fixed, we can often replace it with an opening flat rooflight of similar size, or add a smaller second one beside it that opens. Where a lantern crowns the room, a lantern with opening sashes can pass hot air out of the very top.
How the unit opens is a practical choice, not a fancy one. If you can stand beneath it and reach a handle, manual works. If the glass is high overhead, or you will forget to shut it before you go out, the electric versions make sense, with a small detector that lowers the sash once rain arrives. Solar-powered units need no cable at all, a boon in a room that is already decorated.
Think too about the dull part of the job: what happens inside. A new opening means trimming the roof structure properly, lining the splayed reveal with plasterboard and finishing it in a pale colour so the daylight bounces further into the room. On a bungalow loft that can double the useful brightness of a bedroom. We cover the floor, hang dust sheets on the stairs and make the roof weathertight before we leave each evening, so you are never sleeping under an open hole.
Glass matters here as well. Double glazing with a low-emissivity coating and a warm-edge spacer is a sensible starting point, and a third pane can be worth having in a bedroom that faces the cold. Your quote gives the opening and glazing choices as separate lines, so each can be weighed against the room and the budget. For a broad idea of what moves the price, the costs page is the place to start.
Cooking is the usual culprit in a Clutton family room. A hob and an oven can leave a kitchen-diner stifling before lunch, and steam settles on cold glass. Opening a rooflight above the cooker end helps that moist air leave, while a second opening at the far end lets a breeze run the length of the room. Place the units apart rather than together and the air has somewhere to travel.
Nearby in Paulton and a little further off in Bishop Sutton the housing is much the same mix of stone, bungalow and extension, so what applies in Clutton tends to apply there as well.