Well I have the same issue!
I have spoken to Apple who say there is in fact a problem with the update 7.0.4
My battery drains at about 18% per hour with no use, I do know however what is causing this though!
I live in area with no network coverage at all so my phone provider has given me a Home Signal Box (femtocell)
Which routes all our calls down our high speed internet connection. With our phones connected to this box the box shows a constant green light, when one of the phones is in use the green light flashes.
Since I updated to 7.0.4 when my phone is connected to the box the green light flashes continuosly untill the battery on the phone goes flat. Only I have done the update & only my phone does this.
If I use airplane mode & turn on wifi this stops my phone battery draining & it has been at 100% for the past 14 hours despite me using e-mail & Viber
Apple are replacing my I Phone 5 tomorrow as my warranty expires in two days, all this and there is nothing wrong with the phone! IT IS THE UPDATE
I am guessing that the Facetime fix apparently in this update may be the culprit.
Of course without the benifit of my home signal box I would have never realised that the phone was constantly hammering the cellular network as you can't tell when connect to a conventional phone providers mast.
So Apple engineers if you look at these comments "Have a look at this" this is the problem
I have been a Apple fan for many years but today as my i phone will not last my working day I have resorted to my old Android HTC & you know what it's great
You all have a good day now
Rob (UK)