Assuming that its true and that cold spots more than cold, no ones actually said why..?
They’ve said it happens, but not why...
I’m not talking about speed of clean, or snake oils or how cold your hands get.
I get we can look at windows up close, from the inside and with a microscope... I’m talking of the specific claim that cold spots more than hot water.
If this is true, why?
I’ve used cold and hot with no spotting problems. However, one reason may be that hot water can dissolve more solids than cold water.
In general, solids become more soluble as the temperature increases. This is why sugar dissolves better in hot water than in cold water. The table shows three examples of the solubility (g of solute per 100 g water) of substances at different temperatures.
Sodium chloride
20 deg C : 35.9g
30 deg C : 36.1g
40 deg C : 36.4g
Copper(II) sulphate
20 deg C : 32.0g
30 deg C : 37.8g
40 deg C : 44.6
Potassium nitrate
20 deg C : 47.0g
30 deg C : 61.6g
40 deg C : 77.0g
(
https://www.bbc.co.uk/bitesize/guides/zy8739q/revision/1)
Will this have any effect? No idea, because it depends what the dirt on the window is made of.
That’s something I’ve often wondered, what is it that we are actually cleaning off? Is it mainly salt? Sand? Soil? Something else? Does it differ from place to place? Does it depend on the house ie brick, render, timber?
Anyway, I’ll stick with hot.