We’re frequently asked about the potential of cracking and breaking windscreens that have chips or stars in them as the warm fluid hits windshields at sub zero temperatures.
The simple answer to the question is no, it will not crack the windscreen even if it already has a stone chip or crack.
The Heatshot unit heats the fluid up to 125°F – 135°F (~60°C) within its heating chamber. The fluid, then has to travel through the pipes to the washer jets then onto the windscreen. This reduces the temperature so when it hits the windshield it is only warm and not hot. The warm fluid is sufficient to melt snow and ice but not to penetrate the glass to cause any cracking. The windscreens have a large surface area and the fluid would have to be at least twice the temperature for even the remotest chance of damage being caused.
Years of testing have been carried out in all temperatures and with every type of windscreen both damaged and undamaged. We have never been able to damage any type of screen, and believe me we have tried!