Again, like the shower but even more so, it is in use for so little time - probably 2-5 mins per day - that it is not the place to start worrying about energy saving. I can't really see that a microwave would be that inefficient - I don't notice a great generation of heat (aside from in the food, of course). You need to distinguish between an appliance gobbling electricity, and being inefficient. Making things hot (deliberately) will take a lot of electricity.

We've removed the power shower that was in this house, the cubicle has been installed on its side in a sunny position against a wall. It is now helping to propagate 500 onion seedlings.

Jan

on the microwave subject, they do degrade over time, more current, less power.

The ones in our office are about 3 years old and get used a minimum of 2 hours a day, they take around 5 mins to heat my spag bol. The one at home, that probably gets 2 hours use a month (well, maybe 3 or 4 ) and is a year old does the same job in about 3 minutes.... same nominal rating, 800W, and from the same manufacturer. Tho the cost of getting a new one will probably offset the added electricity used until you get to 15 minutes at full whack.........

I have ordered one now.
But noticed it can hold up to 20 litres of water.

That would be a heavy weight to carry in doors after warming in the Sun.

Do you fill it to the top when you use it in doors??

Or do you shower outdoors ??

Just received my Gelert solar shower.

Realised it has a carrying handle, so the weight problem shouldn't be a problem.
But I think I might have to sit on the shower bowl floor to get under it, when it is hanging up!

I use a hook over the bathroom door, with the door open, and stand in the bath. I replaced the hose with a much longer one so I can effectively swish it around and 'Navy Shower' with it by folding the hose over when I wanted to stop the flow with one hand and fixing it with a peg!

So long as you are below the water in the bag it will syphon out once running.

I fill the bag half full and lay it on the roof or dash of the car, then add cold water to cool it and extend it. I've put a stick through the top of it to make it hang a bit better, IIRR. Bit of broom handle.