If you are after a good long-term investment in heating, look at installing a good radiant electric heater. The benefits over the traditional outdoor gas options are many, including cheaper running costs.
The heat travels through any breeze to hit its intended target and of course not running out of gas. The wiring for these can be pulled through at the time of the patio roof build ready to be hard wired by a licensed electrician. Customers to provide their own external heaters. Please make sure they are compatible with insulated roofing if installing with the roof panel.