It's do-able but really depends on the 14.5 mile, the alternatives and the facilities at your work place.
I used to commute a similar distance from central London to Eastcote a couple of times a week. It took just over an hour. The tube wasn't that much quicker. But it really wasn't a pleasant commute; traffic, roads, grotty surrounds, etc. Plus there were no showers at work. The tube was actually quite pleasant since I was going out of town against the flow. So I wasn't particularly motivated to ride it on a daily basis.
Personally, I'd start with the intention of doing it a couple of times a week and see how it goes. Take it from there.