Turning off hot water heating to save energy

echancrure

I have a gas boiler that heats radiators and a large cylinder for hot water in the hot press.

During summer, we don't need heat from the radiators, and the gas boiler does not fire at all, and we do away with hot running water.

Now with gas prices going up and the winter approaching, I'll want to turn on the heating but without getting hot running water from the cylinder (we do without it, using the kettle for dishes, the showers are electric, we don't take baths).

I checked the boiler it has no setting for radiators only; there is a valve under it, but that's for the radiators.

I turned off a red valve at the bottom of the cylinder: cold water still runs from the hot tap, but the water does not heat up when the boiler is own. So I guess this is the right thing to do.

I have 3 questions, though:

-is it safe to do that?

-how about low water pressure (every year or so, I have to increase the water pressure in the system or the boiler won't fire): the valve for that seems connected to the cylinder (which is now disconnected from the system)

-why is this not promoted as a way of saving energy/money?

mp31

Upgrade your heating controls and get an SEAI grant for this https://www.seai.ie/grants/home-energy-grants/heating-upgrade-grants/. That way you can control your hot water production using a timer (either a basic timer or a smart heating control e.g Hive, Nest etc.)

echancrure

https://www.boards.ie/discussion/comment/119548524#Comment_119548524

Thanks, but I really don't need running hot water. I don't need a 'clever' control to set something permanently off.

We do away with running hot water when the heating is off in the summer, and really thinking about it even in winter we can do without too.

I don't know how much that would save, but given that I have a crappy copper cylinder with a ripped jacket over it, could be about 3 kwh per day in winter. i.e. 30 cents per day or 9 euros a month at least from October to March for 6 months of the year, or about 5% of my gas consumption.

stephenmarr

the red valve is really for flow restriction from the boiler to the cylinder.

either leave it closed or only open it 1 full turn from closed, this will allow a small flow of water through and give you hot water.

whizbang

Any heat you put into a badly insulated cylinder is akin to having a radiator in the hot press. its just going into the house in general. its not actually lost.

Im a bit taken aback that you want no hot water at all.. If when really need it, using the kettle is way more expensive than using the exising gas heat source.

Insulate the crap out of the cylinder, and the hotpress ceiling! turn down the flow to cylinder untill its the temperature you want it, and be smart.

You will save more by just using hot water smartly. The pipe run to the kitchen is quite likely the biggest loss, but again the losss is only into the house; its just another radiator.

echancrure

I think in our household of 2, we probably boil at most the equivalent of 2 kettles (1.7 litres) per day, very often much less (coffee, cooking, some hand-washed dishes, sometimes to wash the floor)

The hot cylinder is in the corner of the house, off the utility and below a bathroom we don't use (and therefore don't heat). It is wasted heat, especially in the summer, of course.

Anyway, for light users of hot water with a hot cylinder and electric showers where you don't take baths, I just thought that a hot cylinder is unnecessary.

Tree

The brother put in a combi boiler and got rid of his cylinder entirely (and recovered the space in the (no longer) hot press too). Might be worth considering. You probably don't want a tank of standing water in your house, so if you have no bath or pumped showers ( I love my pumped shower, that'd be an inducement to keep the tank), you may as well consider getting rid of it.