Powerpal uses ultra high power Bluetooth to connect to your phone (not the same Bluetooth as used in headsets!).
The exact signal range of Powerpal is roughly equivalent to a high qualify WiFi router (50-100m) and just like WiFi the range achievable will vary depending on the environment, for example the number of walls the signal needs to pass through. A good rule of thumb is that if you can get a WiFi signal at your meter box then Powerpal should work well in your home.
If you live in an apartment block and your meter is in the basement then typically Powerpal's signal will reach up to two stories. We cannot guarantee that Powerpal's bluetooth signal will reach through more than two concrete floors between your electricity meter and your home.