Help with drain for Heatpump Integral Unit

I have been asked to install a Powrmatic heatpump unit.
The drain will carry condensate all year round as it is a packaged indoor unit so my worry is that the drain may freeze up in winter when running in heating mode.
The pipe run is approx 8m all outside so i am debating to install a drain heater or whether to just lag the plastic pipe.

Any help would be appreciated. Thanks