To ask how thermostats work?!

[CobaltRose96]

So how exactly do thermostats work?

So, I'm probably being incredibly dense here but we've been living in our flat for nine months now and have finally given in and started putting the heating on. The heating is controlled via a thermostat in the hallway.

So uh, how exactly do thermostats work? I normally set the temperature to 17c (I feel the heat very easily and am currently 8 months pregnant so much above that is uncomfortably warm for me). I understand that setting it to 17c means that the temperature in the flat is maintained at 17c, and the radiators will fire up if it drops below that. If it reaches 17c I assume that means the heating goes off? The radiators are still warm though?

My thermostat has an 'OFF' option. I initially assumed that this was to turn the heating off but I now think it's to turn the thermostat itself off (i.e. There's no set minimum temperature). I'll use this OFF option at nights (even 15c is uncomfortably warm for me at nights) and if I know we won't be in the flat for most of the day and will then set it to 17c when I get up/come home.

So, if I leave the thermostat at 17c and that temperature is maintained, does that mean the heating is on or off? Because I read posts about turning the heating off when you're not in to save money, and that leaving the heating on at a low temperature constantly wastes money, but I thought that if the set temperature is maintained, the heating is off anyway? Is it easier/cheaper for me to continue turning the thermostat off when I'm not home, or simply leave the set temperature at 17c all the time?

So confusing. This is the first time we've lived in our own place and had to deal with the heating ourselves. Can you tell? I have a degree in science so I'm not thick, honest!

Thanks.

Is thete a timer as well as as thermostat? My timer is in the kitchen and controls when the heating/ hot water is on. The thermostat is in the hall. When the heating is set to 'on' the heaters will heat to the level of the thermostat and click on and off to maintain that temperature. When it's set to 'off' there will be no heating regardless of the thermostat setting. My heating is off for several hours during the day and overnight

There are a few different kinds of thermostats.

If it is just a dial with temperatures on, then there should be a timer on the boiler itself. You can set the timer so the heating is on at set times (e.g. An hour in the morning and 3 hours in the evening). The temperature on the thermostat will determine the temperature the boiler will try to maintain during the times the boiler is on. E.g. During the 3 hour evening window, the heating might heat the house to 17.5 so turn off, but once the temperature drops to 16.5 it will come back on.

If your thermostat is a digital one with an LCD display (like a digital watch) there are usually more options.

For example, my old house you could set up to 6 times and temperatures, and vary the days. So on a work day we would have 18 in the morning while we were getting ready, then 5 degrees during the day while we were out, then 18 in the evening and 15 overnight. You couldn't turn it completly 'off' but the setting of 5 degrees did pretty much the same thing seeing as the temperature never dropped that low.

By the way- The radiators will still be warm when your heating is off because they don't cool instantly. They're filled with very hot water so will take their time cooling down like a hot cup of tea! But when the heating is off you will notice less noise from the boiler and the radiators will gradually cool.

To switch my heating on and off e.g. at night, I just turn the thermostat down to 10 degrees. The lowest my flat gets to is around 12 so I know the thermostat won't click on.
I have a very simple digital one with the timer controls on the boiler.

Ok, I have no idea either. My thermostat stays at 22, if I want it hotter, I turn up the heater dial on the boiler. Seems to be far more effective than fiddling with the stat.

OP This depends on your definition of "off".

Whilst the heating is on and the stat is at 17c (or whatever), the system will

a)pump hot water around the radiators
b)switch the boiler on (and off) to maintain the temperature you set on the stat.

So at any given point, the radiators could be warm due to either -
Warm water circulating and the boiler being on
or
Warm water circulating and the boiler being off.

And the system will cycle between the two.

At a certain point, the temp will drop enough for the boiler to kick in.

If you turn the whole lot off - then nothing will happen of course.

If you leave the thermostat at 17 the heating will come on as required. If the heating is off the house will gradually cool down. It's cheaper to turn it off when out or asleep. Most people turn on the heating just for an hour in the morning and a few hours in the evening. It's probably easier to turn it off on the boiler itself rather than changing the thermostat. It will have on/off settings and probably a timer. Sometimes you have to open a panel to see these.
Also you can often turn the radiators down, useful if you want it warmer in one room than another.