Yep you can do it. One problem is that they are noisy. You will want to hide the extractor fans in the ceiling if you vent up out the roof. Bear in mind that

Yep you can do it. One problem is that they are noisy. You will want to hide the extractor fans in the ceiling if you vent up out the roof. Bear in mind that a newer house will be tightly sealed too so your stove/ vent will need it's own air intake as well. I mean you can open a window but I think code will require it to prevent backdraft. Basically the air intake opens when you turn the fan on. Most of your other gas equipment (gas water heater and a gas clothes dryer) will be direct vent though in new builds.