Bubbler Socks?

I noticed that my bubbler is struggling to bubble as it gets colder. I
imagine it will fail, when the real cold gets here. I've seen a few of you
talk about keeping your bubbler inside, but then the condensation builds up
in the long airline. My bubbler only has about 16" of airline attached to
it. So how about heating just the bubbler itself? A few watts should do it,
especially if you could put inside the case. Perhaps something low tech,
like a hunting sock for your bubbler?

Anyone tried any of these or have any better ideas?