perfect amount of heat. need a note on the oven panel to not start up the oven :)) move them under strong grow lights as soon as the seeds germinate. best to have separate pots/trays for different seeds, as tomatoes and eggplant germinate very quick this way. peppers take 4-6 days longer.
i have more soil heating mats now, but i have used the oven light method for years.
also works great later in the season to quickly germinate cucumbers and squash. 