You'd want it warm, but not hot. People flip out when I use water to clear my windshield. COLD water. It's still got enough heat in it to clear things up.

 

Just like cold washer fluid does the job just fine... IE - No value in heated washer fluid LOL.

Now heated wipers I can understand, so that ice doesn't build up on them and they can keep doing their job.

 

But the water coming out of your faucet hasn't been sitting outside at 10 below with your washer fluid, either.

 

It doesn't have any alcohol in it either....at least not until after 5:30!!!!

 

But the alcohol in the washer fluid is also at 10 below, unlike your tap water. 60 degree tap water is going to thaw a lot more ice than -10 washer fluid regardless of alcohol content.

 

Back in the 70's I put a wrap of header tape down then wound about 12" of 1/4" copper tube around the exhaust tube for the washer heater, idea started out for the choke heater.
I always thought a ducted blast of hot air through a heat exchanger at the base of the windshield would clear the snow and ice like a mini snowblower and could keep your windshield warm, blower was either electric or mechanically driven through a magnetic clutch.
Jim

 

I was referring to my glass!! ha ha.

My wipers usually freeze up during our Christmas run over to MT. Its a real pain. I wish I could rig a switch to reverse the heater fan so it would blow back thru the cowl a bit and thaw them out. Not sure if it would work, just thinkin out loud..