a question on behalf of my sister.  She has just bought a new washing machine, and unlike the old one, it only has a cold inlet.

her house has a big solar dhw system, and the water is also heated by her wood stove.  most of the time, she is heating more water than she uses.  would it be acceptable to plumb in the machine to both hot and cold feeds, via a blending valve, to supply water at 30 or 40 degrees (she only ever uses the bog standard 40 degree cycle) so the machine will use "free" hot water from the solar and stove, rather than paying for the machine to heat the water with electric?

On a commercial machine at work, we had to fit a new part which allowed a hot feed too.  It was just a small section of pipework and a second solenoid.  Pretty much all plug and play.  It's almost like the hot feed is just "left out", but can be fitted.

Perhaps google if your model can be done similarly.

The one we did was a commercial machine.

after a quick phone call to the manufacturer, anything other than a cold fill will void the warranty, and it's still got 3 1/2 years left.  ah well, was a nice idea!