I read this today and filed under ‘well I didn’t know that…’
Waterproof membranes typically work by allowing moisture from the warm side of the membrane (against the body) to move through the tiny holes and out to the colder side (outside), but not the other way. If you have heated grips running, this makes the outside of the glove warmer than the inside, which can reverse the action of the membrane. Water gets in from the outside, but isn’t allowed back out!
So does that mean heated gloves can never be water proof?
No, it’s means they have to be warmer on the inside in order to work properly. Like, Huskies.
And we have heated seats too. 
Given the age of some members that may work in their favour. 
Never had a problem with my Rukka waterproof gloves when using my heated grips. Be interesting what other folks experiences are ?
Good shout. Does the theory stand up with people’s real-world experience? I’m not sure, personally. I have experienced wet ‘waterproof’ gloves but that may have been water running in to it from the cuffs.
Not experienced that either but have only ridden for a few winters now and have a very low threshold for using my heated grips (plenty of rain though…I seem to attract it).
I have trouble with heated grips. I find trying to switch them on with my gloves on really difficult, the Vac-Bag keeps getting in the way
I forgot your adventure bike never comes out in the winter. 
It would dissolve before my eyes if I did. BMW quality is shoite, I know this is correct as I read it on the internet. Anyway I seem to recall it was you who recommended the Vac-Bag 
we can’t all afford or have room for more than 1 bike
Ha ha, yes I did recommend the vacsac, but only to support your decision to mothball your bike during the winter. 