Do Peppers seedlings do better with extra warmth?

All my peppers have sprouted nicely and are indoors on a windowsill with plenty of light and tinfoil on the back. I can see the beginning of the first true leaves...
Since they like warmth, would it help them grow better if I kept them in the same sunny position, but put them back in the propagator (without the lid) so they can get more heat from the bottom? And if so, what sort of temperature?

They'll be fine indoors without going back in the propagator

I am trying peppers this year and they have germinated on the window sill. I will bring them on indoors until the summer. I have limited space in my leanto greenhouse. Will they grow outdoors. The patio area is well sheltered and has the sun on it all day.

Thank you jayG: We eat a lot of peppers during the year and it seems logical to grow them. It's one of those things that I will have to try out for myself.