B-right-on
Living the dream
When I run my hot water tap for eg. to do the washing up, it first runs cold for a while. So to save wasting that water I fill up the kettle. Will it kill me?
If you don't have a combi, that water would have sat in a cold water tank in your loft for possibly days, then sat in a large copper tank that's god knows how old for some indeterminate time before you then put it in your kettle.
Ok it then reaches boiling point. But why risk it to save a few pennies over a year.