What is a WiFi site survey?
A WiFi site survey is a structured walk-through of a space in which you measure wireless signal at many points and map the results onto a floor plan. Installers run surveys before deploying access points (a predictive or pre-deployment survey) and after installation to verify coverage (a validation survey). The deliverable is almost always the same thing: a heatmap.
Traditional tools like Ekahau or NetSpot Pro are excellent — and overkill for most homes, rentals, Airbnbs, and small offices. If the question is "where is coverage weak and where should the router or APs go?", a phone-based survey answers it for free.
Passive vs active surveys
| Survey type | What it measures | When to use |
|---|---|---|
| Passive | Signal strength (RSSI) of your network at each point | Coverage mapping, dead-zone hunting, AP placement — 90% of cases |
| Active | Throughput/latency while transferring data | Verifying speed SLAs after coverage is already confirmed |
A phone heatmap app performs a passive survey: it samples signal strength as you walk. That's the right first step — throughput problems in a well-covered area are usually a router or ISP issue, not a placement issue.
How to run a site survey with HeatFi
- Get the floor plan in. Import a blueprint image, photograph a printed plan, or sketch the layout directly in the app.
- Plan your walk. Aim for a sample every 2–3 metres and at least one per room, plus extras at desks and seating areas. HeatFi's guided route suggests where to go next.
- Sample systematically. Stand still for a second at each point and tap Take Sample so the reading settles.
- Read the results. The generated heatmap shows coverage bands and per-room scores. Export to PDF/PNG to share with a client, landlord, or ISP.
When you'd still hire pro tooling
Multi-floor offices with dozens of APs, spectrum-analysis needs (finding non-WiFi interference), or compliance documentation justify enterprise suites. For everything below that, the free survey covers what matters. If you're sizing an office deployment, start with how many access points do I need.
Quick answers
What's the best free WiFi site survey app?
HeatFi is a free heatmap-based survey app for iOS and Android: floor-plan import, guided walk survey, per-room scores, and PDF/PNG export, with all data staying on your device.
Can I do a WiFi site survey without a floor plan?
Yes — HeatFi lets you sketch the layout freehand in the app. A rough plan with correct room proportions is enough for a usable heatmap.
How long does a WiFi site survey take?
A typical home takes about 10 minutes; a small office 20–30 minutes. The survey time scales with area, not complexity.
See your WiFi instead of guessing
HeatFi turns your phone into a WiFi survey tool. Draw your floor plan, walk each room, and get a colour-coded heatmap in minutes. Free — no account needed.
