Wizards and tech... Here we go again
This has been discussed many times, and there's no end in sight.
As far as flavor goes, there are many many ways to describe a hex proof environment. Your's is certainly a viable design. Though i would expect your "magical drainage system" would gobble up any and all magical energies... including those a caster is trying to work with, which would make working spells in that area almost impossible.
From a rules perspective, Involuntary Hexing is a compel. A Compel either gives you fate, or takes fate to avoid.
Therefore i would charge a wizard character who wants to avoid such compels some refresh based on how often one would expect such compels to occur.
For Example:
How often does it occur that a wizard is compelled because technology does not work in his home. My experience is that on average this maybe happens once per seesion.
So if a Player want's total resistance to such compels, he pays 1 refresh up front. Add a colorful description as to why it works. And voila, you're done.
I'd also require this Wizard to have an aspect that incorporates this "love-affair" with technology.
You can then adjust the cost of this "ability" accordingly, if the Hex-Proofing extends to other situations as well.
A totally non-Hexing Wizard would cost at least 3 Refresh, probably more.
that's my take
Then again, i would rather have my rich Wizard have his own big movie room with a vintage projector, an old yet lovingly maintained tube based sound system, and current movies printed on rolls of film specially for his enjoyment.
Wizards fowling up modern tech is an intrinsic part of the Dresden Files setting. So i'd rather see players find amusing ways to do without it, than have them puzzle out ways to circumvent the restriction. but that's just me.