I am using this heater in car and timer function is not good.
First, time itself is every day of 6 minutes "quicker" than it should be, so if you want to use timer function, everytime you have to setup time again.
Timer function - if you want to use timer function, first you have to start engine, it is not possible without this, which is inconvient in case heater is turn off and you want just to setup timer.
But overall it is a very good product for that price, I am using just in the morning to heat up car in freezing weather. From that time is no needed to clean windows from icing.