WiFi heatmaps explained
A WiFi heatmap is a coloured floor plan of radio performance. Green does not automatically mean "good enough for your scanners". Here is how to read an Ekahau survey the way an engineer does.
RSSI (signal strength)
RSSI is received signal in dBm (for example -45 is stronger than -75). Design targets for UK offices often sit around -67 dBm for data and better for voice. A pretty green map that only shows -75 dBm may still drop Teams calls.
SNR (signal-to-noise)
Strong signal in a noisy room still fails. We report SNR as well as RSSI so you can see interference-limited areas - common in city-centre offices and shopping centres.
Secondary coverage and roaming
Clients need a second AP as they walk. Heatmaps of "at least two APs above threshold" predict sticky clients and voice drops. This is why corridor-only AP installs look covered but roam badly.
Channel interference
Too many APs on the same channel is worse than too few APs. Ekahau visualises co-channel interference so we can turn power down or retune channels instead of blindly adding hardware.
Get a heatmap of your site
Book a passive WiFi survey for the live network or a predictive survey from drawings. We explain the pictures in the executive summary, not just dump colour plots.
Common questions
What is a good WiFi heatmap result?
It depends on the application. Offices often target about -67 dBm primary coverage with secondary coverage for roaming. Warehouses must meet that at scanner height, not only at the ceiling.
Why is my heatmap green but WiFi still poor?
Green may show raw signal while SNR, retry rates or sticky 2.4 GHz clients are the real problem. That is why a survey report must include analysis, not only a screenshot.