Does having Wi-Fi and cellular enabled on and iPhone drain battery life?

Whenever I know I'm going to have Wi-Fi for a longer period of time I always shut off my data in settings and just use the Wi-Fi connection. While iOS is built to prefer Wi-Fi over data, does it still shut data off while using a Wi-Fi connection? If both are on but Wi-Fi is being used to transmit data would it use more battery life to keep it on vs. Turning it off?

I have gotten conflicting answers, too - so lately, I have been leaving BOTH on my iPhone 6 when I leave the house. As I'm out about town, I can pick up Time Warner hotpots, ATT hotpots, and public ones with ease (we're obviously TimeWarner and ATT customers). When I do, the symbols on my phone indicate that NO - I'm not using my own data - except if I'm between those hotspots. When I leave the commercial areas, and head up my own residential street, I lose those hotpots, and data kicks in. When I enter my garage/house - the symbol changes back automatically to home Wi-Fi. As far as setting on my phone, I have "ask to join networks" running so it WILL grab those spots automatically, to TWC Wi-Fi in those businesses that have it. I also have data use restricted as far as automatic downloads, I use fetch over push when I can, etc. I utilize the normal things that would save battery and data usage, but an not a total MISER with this, either. I think - and other here who know more, will correct me if I'm wrong - that not that long ago, if you DID have your own data on- it got used FIRST - as a ploy form the service providers to run up your bill! But as consumers got smarter, and therefore phone companies started ACTING more friendly (you still need to read fine print… Wolves in sheep's clothing), they did allow Wi-Fi to be the first choice over data - I'm guessing about the same time they started allowing roll-over data, not just roll-over phone MINUTES (since talk, like text, if unlimited in in all the big providers). I further GUESS that preferring Wi-Fi over your own data also convinced more of us to leave them BOTH running - and therefore picking up hotpots when in motion - and THAT is when providers also decided that they woudl THROTTLE your own data over a certain amount; find a hotpot already, and get off THEIR tower! So - some personal experience, some personal opinion, and some just plain speculation here - i await verification OR correction!

Added- about battery life - people often drain a phone because they have a lot of things RUNNING - either open screens, or background things. You can go in Settings and Usage and there's a list of what are SPACE hogs - and what are BATTERY hogs. Tapping to fetch (instead of constant updates) takes less time than searching for a charging spot!