If I'm not mistaken, I think he needs a solution to prevent ice from freezing the wiper to the windscreen while motoring down the road. I've had that happen on a number of my previous vehicles when getting heavy sleet or in extreme cold after using the washer fluid. If you have freezing rain, slushy sleet, or very wet heavy snow, the wipers can build up a pile of ice, slush, or snow between the bottom of the wiper and the hood/bonnet. After a while in very cold conditions and if you get enough build-up, the wiper can get stuck. I've had instances where the rubber blade itself freezes to the glass and where the whole wiper arm gets lodged in the pile of crud that built-up and is frozen in place. The only car I've ever had with heated wipers (actually heated windscreen where the wipers parked) was my wife's 2010 Subaru Forester 2.5X Premium. Most other cars I've driven have this same problem. The wiper defroster feature doesn't seem to be common on vehicles under $30K sold in the US. It's unfortunate, because it's nice feature here in the colder northern states. I'm not aware of anyone that can retrofit this option either as the heater element is part of the windscreen. You'd have to replace the whole windscreen and then run wiring to power it and install a switch somewhere to turn it on/off unless you somehow rigged it to always be on when the defroster setting is on in the HVAC controls.
Hmm.... I wonder if it would be possible to make some kind of heater element that you could adhere to the windscreen via some kind of adhesive or resin and then run the requisite wiring in through the seal around the glass?