On 09/10/2020 17:25, Dave Liquorice wrote:
On Fri, 9 Oct 2020 13:59:22 +0100, The Natural Philosopher wrote:

When I had a 2 bed flat the HW cylinder would reheat in 20 mins.
When
the time switch died, I didn't bother replacing it, just switched
the
water on when I needed it. Heating was on a room thermostat and
manual on/off switch. BIG drop in gas bill...

You must have lived in a rabbit hutch to have had your CH bills that
low, that reducing the minimal losses through a hot water tank saved you
anything at all...

Top floor 2 bed flat, reasonably (for 30+ years ago) well insulated.
Cold to comfortable less than an hour.

HW went from fireing up twice a day (morning and evening) to reheat
the cylinder to once every 2+ days.

All I know is that I made a significant reduction in the DD to the
gas company...

To get the house up to temperature on a cold morning make that
thee hours,

That's worse than this place, that's high, exposed, draughty and not
overly well insulated. If it's not windy it takes about 90 mins to
reach the target temp on a cold morning. If it's windy and cold the
boiler can barely keep up...

UFH. very very long time constant

... then I switch to 'permanently on', for the CH.

Ours is never off, always on the thermostat. A high thermal mass
means you really don't want the place to cool down otherwise it takes
days, literally, to become comfortable again.

exactly
Not days, but about 12 hours from icy to comfortable if the heat goes
off in serious winter


--
When plunder becomes a way of life for a group of men in a society, over
the course of time they create for themselves a legal system that
authorizes it and a moral code that glorifies it.

Frédéric Bastiat