Frontline just kills fleas. Frontline Combo I believe kills ticks and fleas.
I use Advantix, which kills ticks and fleas, but buy it in from the US without prescription.
Are you treating preventatively, or do you have a flea problem?
If preventatively, I wouldn't treat the house as well.
If you have a flea problem, how bad is it?
The main difference between the two products is that whilst both kill adult fleas, Frontline Combo also prevents eggs/larvae from developing. Having fed on a dog treated with Frontline Combo, an adult flea may still lay eggs before it dies, but they will not develop and the life cycle will be broken.
You obviously know something about this because you ask about treating the house - which is where the eggs are laid, not on the host animal.
As onetwothree says, if you are working preventively then it should not be necessary. However, if your dog suffers from Flea Allergic Dermatitis, then you may wish to take a belt and braces approach by treating the house to kill any viable eggs lying around - and they can lie around for some time waiting for a suitable host.
Yuk.