Local Shutter InstallersSecurity · Survey
The rear bifold as the weak point
Updated
Wide glass at the back is how a lot of houses are entered, because it is private and it is glass. A shutter on that opening is a rational security spend even if the front door is already decent.
What the wall will allow
Locks on the bifold still matter when the shutter is up in the afternoon.
A worked pane
The worked opening for The rear bifold as the weak point is 1.8 m wide by 2.35 m high, 4.23 square metres of glass. This figure puts 570 watts per square metre on the pane and uses a g-value of 0.63, about 1519 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 304 watts and keeps about 1215 watts out. That is a noon figure for comparison. An internal blind does not get the same reduction. For The rear bifold as the weak point, 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.
After dark
Winter figure for The rear bifold as the weak point: glass at 1.2 W/m2K, 4.23 square metres, a 12 degree inside-outside gap and eight night hours. The bare pane is about 0.49 kWh a night on that crude sum. A closed shutter cutting about 18 percent of the flow leaves 0.40 kWh and saves about 0.09 kWh a night, only while it is down. Open it when you want winter sun.
Stop conditions
Stop The rear bifold as the weak point if the only place for the box is a listed street front and nobody has written advice from the council. A photograph is not a manufacturing size.
Reading is only a setting for The rear bifold as the weak point. The streets there are not the product.
How to use the figure
The 1.8 by 2.35 metre opening inside The rear bifold as the weak point 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 £2,561. 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 The rear bifold as the weak point, 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. The rear bifold as the weak point covers one kind of opening. The house may have three.
When I would not order yet
The rear bifold as the weak point 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 The rear bifold as the weak point 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. £2,561 illustrates The rear bifold as the weak point for a 1.8 by 2.35 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 4.23 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 The rear bifold as the weak point 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. The rear bifold as the weak point uses a belt in the example so you can see how much the motor choice moves £2,561.