Calculator Inputs
Example Data Table
| Scenario | Window Style | Windows Secured | Panels/Window | Tamper | Spares | Total Sensors |
|---|---|---|---|---|---|---|
| Ground-floor retail | Sliding | 18 | 2 | Yes | 8% | 42 |
| Two-floor office | Casement | 24 | 1 | No | 10% | 27 |
| Apartment podium | Single-hung | 60 | 2 | Yes | 5% | 189 |
| School corridor | Awning | 30 | 1 | No | 7.5% | 33 |
| Fixed glazing scope | Fixed | 12 | 1 | No | 0% | 0 |
Example totals are illustrative. Site standards, sensor models, and mounting details can change the final count.
Formula Used
Direct mode uses your total. Floor mode multiplies average windows per floor by floors to secure.
WindowsSecured = WindowsTotal or FloorsToSecure × WindowsPerFloorAn effective minimum is chosen using window style and opening panels.
SensorsPerWindow = max(StyleMultiplier, PanelsPerWindow)If enabled, one extra sensor is added to each secured window.
Tamper = WindowsSecured × 1 (when enabled)Spare units cover rework, breakage, and commissioning adjustments.
Total = round(subtotal × (1 + Spares%))Style multipliers are common estimating defaults. Always align with your security spec, sensor model, and installer method statement.
How to Use This Calculator
- Pick a counting method based on your project survey detail.
- Select the window style that matches most openings in scope.
- Enter opening panels per window to reflect real operable sections.
- Enable tamper and fixed-window security only if specified.
- Choose spares and rounding, then press Calculate.
After you calculate, use the download buttons to export a job-ready CSV or a printable PDF summary for bids, submittals, and site coordination.
Scope Planning for Window Contacts
Accurate counts start with a security scope. Separate windows that must be monitored for intrusion from those protected by fencing, glazing film, or motion zones. For buildings with mixed occupancies, create a schedule by façade and occupancy, then validate counts during site walkdowns. Note elevation and access features that influence which levels are included. Capture window IDs during surveys to speed procurement, labeling, and cross-checking during commissioning and final turnover documentation closeout packets.
Interpreting Window Style Multipliers
Different opening mechanisms drive contact placement. Sliding and hung styles often need two monitoring points to confirm sash position, while casement and awning windows typically require one contact on the leaf. Use the panels-per-window input to reflect multi-panel units and corner assemblies. If your standard detail requires extra confirmation points, treat that window as two or more sensors.
Using Floor-Based Estimating
Floor mode supports projects where only lower levels require sensors due to access risk. Multiply average windows per floor by the secured floors count, then refine with punch-list adjustments for stairwells, podium setbacks, and screened terraces. This approach reduces over-ordering on upper levels. For larger projects, split averages by wing or gridline so the estimate matches façade density. Update assumptions after framing and glazing surveys.
Allowance Strategy for Spares and Rework
A controlled spare rate protects schedules. Typical allowances range from 5% to 10% for standard installations, increasing for fast-track fit-outs, high breakage risk areas, or phased handovers. Rounding up is recommended to avoid shortfalls when packaging sensors into zone kits. Track spares by phase and location; losses often occur during close-out, cleaning, and punch work.
Documentation, Testing, and Handover Metrics
Use the exported summary as a baseline for submittals and commissioning. Track sensors per window and tamper additions against shop drawings, then record functional tests by zone. Final counts should reconcile with as-built schedules, labeling maps, and acceptance test results for compliance. Many teams target 100% zone verification plus a retest rate below 2% after rectification.
FAQs
1) How many sensors does a typical window need?
Many casement and awning windows use one contact. Sliding and hung styles often use two. Confirm with your security specification and the sensor model’s mounting guidance for the required detection points.
2) Why does the calculator use both style and panels per window?
Style multipliers reflect common practice, while panels capture real operable sections. The calculator uses the higher value to avoid undercounting multi-panel assemblies where extra contacts are typically required.
3) Should fixed windows ever be included?
Fixed glazing is often excluded because it does not open. Include it only when the project requires monitoring for forced entry, removable stops, or specific risk conditions defined by the security consultant.
4) When should I add a tamper sensor per window?
Add tamper sensors when specified for high-security openings, exposed wiring routes, or locations with frequent public access. Some systems use combined contacts with built-in tamper, so verify device capabilities before ordering.
5) What spare percentage is reasonable for ordering?
A 5% to 10% spare rate is common for standard projects. Use higher spares for phased installs, remote sites, or tight commissioning windows where replacement lead times could delay handover.
6) How do I use the exports in a project workflow?
Attach the CSV to material takeoffs and procurement logs. Use the PDF for bid packages and site coordination meetings. After commissioning, compare exported totals with as-built schedules to confirm installed quantities.