Revenues rocketed 130% to a record £96.4m, driven by growth in its comparison services division, which alone totted up sales of £57.7m.
Zoopla acquired the energy switching firm last year.
Chief executive Alex Chesterman said: "We have seen a particularly strong performance in our comparison services division with record switching volumes in both the energy and communications verticals.
"Over the past six months, we have helped save consumers over £175m on their household energy bills alone."
Zoopla saw more than 300 million people visit its property website after listings grew to 854,000.
Anthony Codling at broker Jefferies said: "Zoopla's first half results demonstrate to us that its performance is on the up.
"uSwitch is performing strongly and the group expects full year 2016 EBITDA (earnings) to be at the top end of market expectations. We reiterate our buy rating on the shares."