[meldrewreborn]

@geoffers

A number of my neighbours have their boiler in the loft, although that's not a usable room. The heat radiated by the boiler is therefore lost - more money than sense!

[retrotecchie]

@meldrewreborn

My boiler is in the garden. External boilers are not for everyone, especially if you have a small garden or live in a flat, but I would never have an indoor one again.

[geoffers]

Originally Posted by meldrewreborn

@geoffers

A number of my neighbours have their boiler in the loft, although that's not a usable room. The heat radiated by the boiler is therefore lost - more money than sense!

In terms of the overall losses, i should think the percentage of heat lost from the boiler itself is minimal.

When I boxed mine in there were certainly airflow requirements to allow for heat/cooling air to circulate, but the unit itself doesn't radiate much heat - the majority of the heat lost is blown out of the flue itself

[meldrewreborn]

@geoffers

Every little helps!

[TAYLOROY]

My gas usage last night was 5.3 kWh for hot water, IHD shows 69p, 29p of it is standing charge.

its a three story property with the water tank on the top floor and boiler on the ground floor.

will do a similar test with immersion heater to see difference, but it looking promising

[meldrewreborn]

@TAYLOROY

Unless you are on E7, E10, or a modern EV tariff its not likely to be financially attractive. I think @geoffers was paying less than 10p per kWh on his EV tariff for the time period the test was conducted.

[TAYLOROY]

@meldrewreborn

i am switching next week to next drive so maybe worth looking into.

[TAYLOROY]

@geoffers

I’ve had another thought, our tank is 180 Ltr and there are only two of us, I’ve stitched to putting it on 5am for two hours to see if we still have hot water all day.

[geoffers]

Originally Posted by TAYLOROY

@geoffers

I’ve had another thought, our tank is 180 Ltr and there are only two of us, I’ve stitched to putting it on 5am for two hours to see if we still have hot water all day.

👍 - I set mine on @ 6am and the 3kW immersion reaches 60⁰C in about 40mins (depending on the initial temp) so it stops running then.

I've got an electric shower & dishwasher, so previously had actually stopped using my h/w tank as I could cope with just the occasional kettle for one off hot water needs.

However about 40 mins on cheap leccy now lasts me all day, and if I want a bath once in a while for instance, just bung both heat sources on for ~ ¼hr (easy to do with that smart immersion switch 🤓)

[geoffers]

Originally Posted by meldrewreborn

...., if its lost inside in winter it just reduces the cost of home heating, so in my view neutral....The best cost advantage might be gas heating of your hot water in winter and electric in summer.

@meldrewreborn @TAYLOROY : you're dead right...

Thinking this through again, what I've been testing was of course the summer situation. Here the feed water temperature is starting from cold so certain amount of extra energy is needed to bring this up to temperature, then at the end heat is wasted as the feed is still hot when the thermostat turns everything off

In the winter the feed water is already hot for the central heating, and the cylinder gets first dibs with the feed at its hottest temperature. Once the boiler thermostat is satisfied there is no wasted feed heat as that goes straight into the radiators

Over the day potentially around 10% of the cylinder temperature will be lost to the house but as you say in the winter that is adding to the overall central heating, so not a loss. During the day the tank thermostat will occasionally ask for a little extra from the already hot feed, but the energy taken will probably be minimal.

So I'm now thinking that in the winter all that would be required is maybe a little help from the immersion (possibly ¼ hr) which would assist the system in achieving the initial tank temperature - or maybe not bother at all in the winter 🤓