I have always had trouble getting seeds to germinate, therefore I have purchased a propagator to help. Ideally I would have a thermostatically controlled unit, but they tend to be a bit more expensive, and non-looked like they wood fit nicely on a windowsill.

Garland Super7, should raise soil temperature by 8 degrees but fluctions of indoor temp will be passed on:

Propagator

Hopefully I will have some better luck in the future.