Best answer by Jon1
There are 2 ways to do this.
1. Download the app onto a second device and then sign up using a second email address (Thats imperative). Get a quote and switch as you did for your main house
2. Log out of the app you use for your main house. Then instead of logging in get a quote and sign up again using a second email address.
The important fact is that currently each acct has to be registered with its own email acct. I have 2 accts and on one device and simply log out and back in again to switch accts once a month to give readings. Bit of a faff but its only once a month.