I think we are all intelligent and experienced enough to work out whether we need steaming hot water or not, and I reckon 99% of us don't.
However, there is more of an argument for a inexpensive, simple and effective solution to widening the scope of opportunity in subzero temperatures for working, with the added benefit of also keeping your entire system frost free. It comes in the form of a high power electric heating element (immersion) and at £4800 cheaper than a diesel water heater- makes it a very economical and attractive option. Add to that, it's also maintenance free, as simple as plug in, switch on, less expensive to run than it's diesel alternative and it becomes pretty much a no brainer for the vast majority window cleaners.
Also, at around £200/£250 all in, including parts and professional 16amp line installed from consumer unit you won't have to spend all day, every day trying to convince everyone else and their mother that you've made the right decision!!👍
