“Sensor window” means two different things in the UK, and the cost differs by orders of magnitude. For a home alarm, a door or window contact sensor costs roughly £10 to £35 to buy and about £30 to £230 fitted, depending on who installs it and how many you need. For an OEM, a sensor window is a precision glass component, and its price depends on the specification, not a shelf tag. This guide covers both, starting with the household figures most searchers want, then moving to how engineers and buyers should think about the cost of optical sensor glass.
TL;DR
- Supply-only door and window contacts typically cost £20 to £30 on average in the UK, with budget smart-home units from under £10 and branded alarm contacts from about £31 to £35.
- Fitted by a professional, a door or window sensor averages £170 to £230 according to one UK cost guide, though other installers quote £30 to £60 per added sensor.
- Price moves with wired versus wireless, system brand, monitoring, accreditation and where in the UK you live.
- For industrial sensor windows, cost follows glass type, tolerances, coatings, edge work, quantity and traceability. Quote it from a drawing, not a catalogue.
Table of Contents
- What a window sensor costs to buy in the UK
- Installed cost: what you pay when a professional fits it
- What moves the price of a window sensor
- Where to fit window sensors so the money works
- Compatibility: check before you buy
- Sensor windows in industry: why there is no shelf price
- Our perspective
- Request a quote for custom sensor windows
- A short checklist before you ask any supplier for a price
- FAQ
- Sources
What a window sensor costs to buy in the UK
A window sensor, more accurately a contact sensor, is a two-part device. One part is fitted to the frame and a magnet to the moving window or door. When the window opens, the contact breaks and a signal goes to the alarm keypad. It detects opening, not breakage, which matters for the price comparison later.
For supply only, MyJobQuote puts door and window sensors at £20 to £30 on average. Individual listings sit around that figure and spread widely:
| Type of sensor | Listed price | Notes |
|---|---|---|
| Budget Wi-Fi or hub-based smart sensor | £9.99 including VAT | Hub included, works with several smart-home platforms |
| Budget Zigbee sensor | £11.99 including VAT | Needs a Zigbee hub |
| Contact sensor for a specific alarm ecosystem | £18.49 sale price | Designed for that brand’s alarm integration |
| Branded alarm contact, retailer listing | £31 excluding delivery | Wireless range stated up to 200 metres, compatible with specified systems only |
| Branded alarm contact, manufacturer listing | £34.99, installation not included | Compatible with the maker’s own alarm range |
| Professional-grade combined vibration and contact | From £75 excluding VAT | Installer-supplied |
The pattern is simple. Sensors that talk to an open smart-home standard are cheapest. Sensors locked to one alarm brand cost more, but they save you from buying a second controller. Installer-grade contacts cost most again because they come with certified equipment and a warranty on the fitting.
One UK guide says individual alarm sensors commonly range from £20 to £100 and that many homes use six to 12 of them. That range is the realistic budget line for a whole-house count.
Starter kits against single sensors
If you have no alarm at all, a single contact is no use alone. CrimeRate reports starter-kit equipment from £100 to £359 across the UK brands it surveyed. Adding extra equipment later is usually cheaper per unit: MyJobQuote suggests about £30 for an additional door sensor, while a complete add-on set can reach £100 or more.
Installed cost: what you pay when a professional fits it
Installation is where the bill changes. MyJobQuote lists installed door and window sensors at £170 to £230 on average. Other sources are much lower for adding a sensor to an existing system:
- J&L Security says adding a sensor typically costs £30 to £60 installed, with an additional door contact listed from £45 excluding VAT.
- Satfocus Security gives an indicative £90 to £140 installed per sensor in London, with the final figure dependent on quantity and mounting.
The gap is not a contradiction. A £30 to £60 add-on assumes an installer is already on site or the panel exists. A £170 to £230 average often reflects a callout on a fresh job, with travel, labour and sometimes a controller.
For a whole new alarm, the sensors are part of a bundle. Checkatrade gives a starting supply-and-install price of £525 for a basic wireless bell-only alarm with two sensors and one door contact, and £500 for the wired equivalent. CrimeRate’s 2026 survey averages £562, split into £269 of equipment and £293 of installation. Satfocus Security quotes £299 as a starting price for basic wireless setups, with professional installation adding £150 to £400.
What moves the price of a window sensor
Checkatrade lists the main variables: property size, number and type of sensors, system type, wired versus wireless, cabling, installation complexity, monitoring and location. In practice, six factors do most of the work.
- Wired or wireless. Wireless can cut disruption and labour, while wired systems may need extra cabling and installation time.
- Ecosystem lock-in. A cheap sensor that cannot talk to your panel is money wasted. Check the compatibility line before buying.
- Grading and accreditation. Graded, accredited installations cost more because certified equipment, procedures and monitoring may be needed for police response or stricter insurance terms.
- Monitoring and smart integration. MyJobQuote adds professional monitoring, smart-home integration and installer accreditation as cost factors.
- Location. London and the South East can run around 20% above the UK average, and MyJobQuote also notes higher labour rates in cities and the South East.
- Running costs. Annual maintenance commonly costs £80 to £200, which belongs in any honest cost comparison.
Where to fit window sensors so the money works
Buying sensors for every window is rarely necessary. Security.org advises fitting contacts on accessible ground-floor windows that open, mounting the transmitter and magnet within one inch of each other without obstructing the opening, then testing with the alarm armed. Fixings are adhesive or screws.
A contact sensor does not notice a pane being smashed while the frame stays shut. For fixed or non-opening glass, a separate glass-break sensor is the right device, and it is priced differently. Budget for both kinds where a ground-floor window is large or fixed.
Compatibility: check before you buy
Most price complaints are really compatibility mistakes. Manufacturers list which alarm range their contact works with, so match the sensor to the panel or hub you already own. The cheapest unit in the table is only good value if it joins your existing system. When in doubt, buy from the same range as the panel, or choose an open-standard sensor with a hub that supports the platforms you use.
Sensor windows in industry: why there is no shelf price
If you arrived here looking for the glass that protects an optical sensor, camera, lidar head, scanner or instrument, the home-alarm figures above do not apply. A sensor window in that sense is a precision glass component placed in front of a detector. It must pass the right wavelengths, resist the environment and seal against a housing. Its price comes from the specification.
We do not publish prices for our components, because each one is built to a drawing. What we can set out is what drives the figure, so your RFQ gets a quote you can compare.
The cost drivers we see on a drawing
- Glass type and grade. Optical performance, transmission range and strength requirements decide the substrate. Our guide to specifying glass for optical sensors walks through the choices, and for specialised bands see our notes on UV sensor windows and infrared window glass.
- Size, thickness and flatness. Tighter surface and wavefront requirements mean more grinding and polishing time and more inspection.
- Tolerances. Dimensional limits on outline, holes and slots set the machining effort. See our pages on CNC glass machining and glass slot machining.
- Edge finishing. Chamfers and polished edges protect against chipping and affect the strength of the finished part.
- Strengthening. Toughened or chemically strengthened glass adds a process step and sets limits on what can be machined afterwards, so the order of operations matters.
- Coatings and printing. Anti-reflective or anti-glare coatings, and ceramic printing for masks and borders, add steps and test requirements.
- Environment. Pressure, immersion and sealing requirements change the design. Our guides on pressure window design, underwater sensor windows and gasket sealing specifications cover what to define before you ask for a price.
- Quantity. Setup and programming cost is spread across the batch, so a prototype run and a volume run price very differently. We scale from prototype to volume.
- Documentation. Batch-level traceability, inspection reports and export compliance paperwork are part of the job in defence, aerospace and medical work.
A worked comparison, without invented numbers
Take two requests for a round cover window of the same diameter. The first is a plain, edge-ground window for an indoor instrument, 50 pieces, with a generous thickness tolerance. The second is a chemically strengthened, anti-reflective window with a ceramic-printed border, a polished chamfer and a flatness requirement, 500 pieces, with batch traceability. Same diameter, same shape, yet the second involves more process steps, more inspection and more documentation per piece. Setup spreads over more units, which lowers the unit cost, while the extra operations raise it. That is why a quote needs the full specification and not a size alone.
Our perspective
Buyers often ask us for a price per window before they have fixed the specification. We understand why: procurement needs a number. But in precision glass, the number is the result of decisions made on the drawing.
Our view is that the cheapest route to a lower unit cost is a complete, realistic specification. Define the wavelength band, the tolerance that actually matters, the edge condition, the coating and the environment, and separate what is critical from what is simply inherited from an earlier design. Over-specifying a non-critical tolerance adds machining and inspection time without improving the sensor.
We work to ISO 9001, keep production traceable at batch level and scale from prototype to volume, so the part you approve at ten pieces is the part you receive at ten thousand. For defence, aerospace and medical customers that consistency, with documentation that stands up to audit, is worth more than a headline price.
Alexandra
Request a quote for custom sensor windows
If you are an engineer or buyer at an OEM who needs optical windows, display glass, scanner glass or protective covers made to drawing, we design, fabricate and deliver them for medical device, defence, aerospace, automotive, lighting, electronics and marine customers. Our services include cutting, CNC machining, edge finishing, toughening, lamination and coating, and our optical components range covers lenses, beam splitters and filters.
Send us the drawing, quantity and application, and we will tell you what the part involves. Start from our technical glass page or contact us through the main site.
A short checklist before you ask any supplier for a price
Whether you are pricing a household alarm or an optical window, the same discipline saves money.
- Write down the count. Home: how many openings need contacts and how many need glass-break detection. Industrial: prototype quantity and expected annual volume.
- State the compatibility. Home: panel or hub model. Industrial: housing, seal type and mating parts.
- Separate supply from fitting. Home: ask whether the quote includes installation, VAT and any callout fee. Industrial: ask whether coating, inspection reports and packaging are in the unit price.
- Ask about running costs. Home: monitoring and maintenance. Industrial: re-order lead time and change control.
- Compare like with like. Three quotes only help if all three cover the same scope.
FAQ
How much does a window sensor cost in the UK?
Supply-only contact sensors average £20 to £30, with budget smart units below £10 and branded alarm contacts around £31 to £35. Installed, expect anything from about £30 to £230 per sensor depending on whether it joins an existing system.
Do I need a sensor on every window?
No. Focus on accessible ground-floor windows that open, and use glass-break detection for fixed panes that a contact cannot protect. Upper-floor windows are a lower priority unless they are reachable from a roof or extension.
Why do installed prices differ so much between quotes?
Scope differs. Some quotes cover only an extra sensor on a working panel, while others include a callout, a controller or monitoring. London and the South East can also be around 20% higher than the UK average, so always compare line by line.
What decides the cost of a custom sensor window for a product?
Glass type, size, tolerances, edge finish, strengthening, coatings, environment, quantity and documentation all matter. Because these vary by drawing, we quote from your specification rather than a price list.
Sources
- Security.org: How Do Window Alarm Sensors Work?
- Vivint: How Do Window Sensors Work?
- MyJobQuote: Home security cost
- Yale Home UK: Indoor Window/Door Contact
- Wickes: Yale Smart Living Door & Window Contact
- Amazon UK: SONOFF SNZB-04P Zigbee Door Window Sensor
- SND Electrical: Ring Alarm Contact Sensor (2nd Gen)
- Amazon UK: Meross MS200 Smart Door and Window Sensor
- CrimeRate: Burglar alarm cost guide 2026
- Third Eye Integrated Security: Burglar alarm cost in the UK 2026
- Checkatrade: Burglar alarm installation cost in 2026
- J&L Security: Burglar alarm cost UK 2026
- Satfocus Security: DoorProtect door and window sensor, London
- Satfocus Security: Burglar alarm systems UK guide 2026
