No, I don't mean PWM to hold the valve partially open. I mean pwm like 10 sec on/ 50 sec off, like that. With igniter, safety valve, all that rot.
I don't think that you can throttle a gas burner over a wide range as you are assuming.
Once you've priced propane, you may go back to electricity.
Mike Halloran
Pembroke Pines, FL, USA