Local Shutter InstallersOpenings · Survey
Bay windows
Updated
A curved or faceted bay is an awkward roller. Separate flat curtains on each facet are sometimes possible and often ugly.
Sun, in watts
The worked opening for Bay windows is 1.8 m wide by 1.2 m high, 2.16 square metres of glass. This figure puts 645 watts per square metre on the pane and uses a g-value of 0.63, about 878 watts into the room if the curtain is up. An opaque external shutter, taken as stopping 80 percent of that gain while it is fully down, leaves about 176 watts and keeps about 702 watts out. That is a noon figure for comparison. An internal blind does not get the same reduction. For Bay windows, use the noon figure to compare two openings on the same house, then let a measured survey replace the figure.
An internal blind does not get that reduction, because the energy has already crossed the glass.
On this opening
Internal plantation or a shaped internal shutter is frequently the better bay answer. Forcing a straight cassette across a bay is how boxes end up proud of the brick by a ridiculous amount.
The same glass in winter
Winter figure for Bay windows: glass at 1.2 W/m2K, 2.16 square metres, a 12 degree inside-outside gap and eight night hours. The bare pane is about 0.25 kWh a night on that crude sum. A closed shutter cutting about 18 percent of the flow leaves 0.20 kWh and saves about 0.04 kWh a night, only while it is down. Open it when you want winter sun.
I would not order yet
Stop Bay windows if the door is an escape route and the motor has no way to open when it is dead. A photograph is not a manufacturing size.
Brighton is only a setting for Bay windows. The streets there are not the product.
How to use the figure
The 1.8 by 1.2 metre opening inside Bay windows is there so a quote has something to disagree with. If the tape gives a different size, the tape wins.
The example drive is a belt, and the illustration is £1,704. A belt, a wired motor and a solar motor can share a curtain and still be different jobs. Compare those lines, not a single bold total.
What the survey still has to write down
For Bay windows, ask where the box lands, what colour reference will be ordered, and how the curtain opens when the motor is dead. Those three answers move the job more than a rounded price.
Leave the lantern, the side light and the next elevation off the order unless they are drawn. Bay windows covers one kind of opening. The house may have three.
When I would not order yet
Bay windows should wait if the opening is an escape door with no way to raise a dead motor, or if the front is the elevation a conservation area was drawn to protect.
A photograph is not a manufacturing size. Two quotes for Bay windows only compare when the slat, the box and the drive are the same kind of thing.
Questions worth asking the fitter
Is the price on this page a quote?
No. £1,704 illustrates Bay windows for a 1.8 by 1.2 metre opening with a belt, at September 2026 rates. Your survey replaces it.
Does the shutter cover every pane?
It covers the opening it is built for. Here that example is 2.16 square metres. A roof lantern, a side light or the next elevation is another line.
What if planning is unclear?
Do not pay the factory for Bay windows until a listed building, a conservation front, a flat or a shopfront has a written answer. Ordinary rear walls on houses are sometimes simpler.
What should two quotes share?
The same openings, the same slat type, and the same drive. Bay windows uses a belt in the example so you can see how much the motor choice moves £1,704.