Local Shutter InstallersWinter · Season
U-value and a closed roller shutter
Updated
Window U-values describe the glass and frame, not the glass plus a shutter. A closed external curtain adds an air gap and can cut the heat flow through that opening while it is down.
When the curtain has to be down
European shading guidance treats this as real and limited. It is not a new U-value for the whole house, and it is zero help at 11am if the curtain is up.
A size you can argue with
The worked opening for U-value and a closed roller shutter is 4.2 m wide by 2.1 m high, 8.82 square metres of glass. This figure puts 570 watts per square metre on the pane and uses a g-value of 0.76, about 3821 watts into the room if the curtain is up. An opaque external shutter, taken as stopping 90 percent of that gain while it is fully down, leaves about 382 watts and keeps about 3439 watts out. That is a noon figure for comparison. An internal blind does not get the same reduction. For U-value and a closed roller shutter, 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.
The night cover
Winter figure for U-value and a closed roller shutter: glass at 2.6 W/m2K, 8.82 square metres, a 12 degree inside-outside gap and eight night hours. The bare pane is about 2.20 kWh a night on that crude sum. A closed shutter cutting about 30 percent of the flow leaves 1.54 kWh and saves about 0.66 kWh a night, only while it is down. Open it when you want winter sun.
A bad reason to proceed
Stop U-value and a closed roller shutter 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.
Derby is only a setting for U-value and a closed roller shutter. The streets there are not the product.
How to use the figure
The 4.2 by 2.1 metre opening inside U-value and a closed roller shutter 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 solar motor, and the illustration is £5,857. 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 U-value and a closed roller shutter, 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. U-value and a closed roller shutter covers one kind of opening. The house may have three.
When I would not order yet
U-value and a closed roller shutter 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 U-value and a closed roller shutter 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. £5,857 illustrates U-value and a closed roller shutter for a 4.2 by 2.1 metre opening with a solar motor, 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 8.82 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 U-value and a closed roller shutter 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. U-value and a closed roller shutter uses a solar motor in the example so you can see how much the motor choice moves £5,857.