Local Shutter InstallersWinter · Season
Trickle vents versus a fully closed curtain
Updated
Modern windows often have trickle vents so the house still gets background air. A shutter across the vent can block that path if it seals the whole opening.
What the glass admits
The worked opening for Trickle vents versus a fully closed curtain is 1.2 m wide by 1.2 m high, 1.44 square metres of glass. This figure puts 495 watts per square metre on the pane and uses a g-value of 0.7, about 499 watts into the room if the curtain is up. An opaque external shutter, taken as stopping 85 percent of that gain while it is fully down, leaves about 75 watts and keeps about 424 watts out. That is a noon figure for comparison. An internal blind does not get the same reduction. For Trickle vents versus a fully closed curtain, 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 hot part of the day
The survey should look at where the vents are. Blocking them by accident is how a warm room becomes a stuffy one.
Dusk in January
Winter figure for Trickle vents versus a fully closed curtain: glass at 1.4 W/m2K, 1.44 square metres, a 12 degree inside-outside gap and eight night hours. The bare pane is about 0.19 kWh a night on that crude sum. A closed shutter cutting about 24 percent of the flow leaves 0.15 kWh and saves about 0.05 kWh a night, only while it is down. Open it when you want winter sun.
Leave it if
Stop Trickle vents versus a fully closed curtain if the solar panel would sit in a soffit with no sky, and the quote has no wired alternative. A photograph is not a manufacturing size.
Sheffield is only a setting for Trickle vents versus a fully closed curtain. The streets there are not the product.
How to use the figure
The 1.2 by 1.2 metre opening inside Trickle vents versus a fully closed curtain 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 wired motor, and the illustration is £1,509. 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 Trickle vents versus a fully closed curtain, 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. Trickle vents versus a fully closed curtain covers one kind of opening. The house may have three.
When I would not order yet
Trickle vents versus a fully closed curtain 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 Trickle vents versus a fully closed curtain 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. £1,509 illustrates Trickle vents versus a fully closed curtain for a 1.2 by 1.2 metre opening with a wired 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 1.44 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 Trickle vents versus a fully closed curtain 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. Trickle vents versus a fully closed curtain uses a wired motor in the example so you can see how much the motor choice moves £1,509.