Check Your Room Thermostats

Les_Nutmeg

We keep our Gas C/H on 24 hrs per day, we have a thermostat in the cool hall (stupid place for a regulator) but find that 20c setting provides correct temp for main rooms in the house, suggest that gas usage is slightly less due to fact that once house temp has reached set level the boiler is ticking over in order to maintain temp, if it went off at say 22.00 hrs house gets very cold overnightand when it switches on say 6.00 hrs it is working flat out for ages and uses much more gas than is used on 24 hrs tick over. We like a cold bedroom so switch that rad. off and open window but keep bedroom door firmly closed in order not to lose expensive BTU,s out of window. Any thoughts!

Cardew

Les_Nutmeg wrote: »

We keep our Gas C/H on 24 hrs per day, we have a thermostat in the cool hall (stupid place for a regulator) but find that 20c setting provides correct temp for main rooms in the house, suggest that gas usage is slightly less due to fact that once house temp has reached set level the boiler is ticking over in order to maintain temp, if it went off at say 22.00 hrs house gets very cold overnightand when it switches on say 6.00 hrs it is working flat out for ages and uses much more gas than is used on 24 hrs tick over. We like a cold bedroom so switch that rad. off and open window but keep bedroom door firmly closed in order not to lose expensive BTU,s out of window. Any thoughts!

Welcome to the forum.

Yes! Plenty of comment.

Your theory, which is an urban myth a lot of people believe, is complete tosh I am afraid.

It is always cheaper to switch it off!!

That statement of mine supported by the the laws of physics, confirmed by the Energy saving Trust and any other publication you care to read.

Using your theory it would make sense to keep your kettle boiling all day rather than let it get cold; it really is the same principle!!

Discussed many times on MSE and comes up time and again.

I am not trying to 'put you down' as I can understand your reasoning, but I am afraid it is flawed reasoning.

Sorry! Hope it doesn't stop you contributing in future.

mute_posting

Les_Nutmeg wrote: »

We keep our Gas C/H on 24 hrs per day, we have a thermostat in the cool hall (stupid place for a regulator) but find that 20c setting provides correct temp for main rooms in the house, suggest that gas usage is slightly less due to fact that once house temp has reached set level the boiler is ticking over in order to maintain temp, if it went off at say 22.00 hrs house gets very cold overnightand when it switches on say 6.00 hrs it is working flat out for ages and uses much more gas than is used on 24 hrs tick over. We like a cold bedroom so switch that rad. off and open window but keep bedroom door firmly closed in order not to lose expensive BTU,s out of window. Any thoughts!

You pay to heat your house up, then when you goto bed you turn off the rad and open the window slightly and rely on your bedroom door to hold the heat in the rest of the house?

I'm pretty sure it is completely wrong, I'm sure someone will explain the finer points.

I would say that the boiler probably uses LESS energy overall if it was working flat out in the morning and the afternoon / and off when the house is empty, than it does just ticking over 24/7

To me that is like keeping a pan simmering all day and then chucking come cold water in when you want it a bit cooler.

Just my opinion

MP

EDIT

looks like I was thinking and typing exactly the same thoughts as cadrew lol

george1939

Les Nutmeg Cardew is correct your method will only 'increase' the kilo watts used each year and so huge increases in your yearly spending on gas

Conor_3

Cardew wrote: »

It is not satisfactory for the temperature of the living room or hall to determine the temperature in every other room in the house.
In your case why should the temperature in your living room determine the temperature of the bathroom, bedrooms etc.

With a TRV you can set the temperature of each room individually. For instance regardless of the temperature in my lounge, I can have a bedroom set to off right up to max heat(26C or so)

OK, so it regulates what the temperature in the rest of the house but I'm still not seeing the point. Surely it means your central heating has to be running a lot more of the time so those set higher than I would have the thermostat in my living room would be able to maintain the temperature?

I'm not trying to wind you up - I honestly can't see how it is saving money. I can see how it would stop the situation of someone winding up the thermostat downstairs because it was cooler upstairs for example. Is that the reason because in my case then, it won't apply.

Cardew

Conor wrote: »

OK, so it regulates what the temperature in the rest of the house but I'm still not seeing the point. Surely it means your central heating has to be running a lot more of the time so those set higher than I would have the thermostat in my living room would be able to maintain the temperature?

I'm not trying to wind you up - I honestly can't see how it is saving money. I can see how it would stop the situation of someone winding up the thermostat downstairs because it was cooler upstairs for example. Is that the reason because in my case then, it won't apply.

I appreciate that yours is a genuine query, and at times it is difficult to grasp the theory.

Take this situation.

I want the temperature in my living room to be, say, 22C.

I want my bathroom to be at 26C

Bedroom 1 to be at 18C

Bedroom 2 at 24C cos thats where my kids play on their PC in the evenings in their pyjamas.

Kitchen to be at 16C cos I am slaving over at hot stove!!

Hall to be at 16C cos it doesn't matter about that being warm.

Now if your heating is only controlled by a wall(room) thermostat in your living room or in your hall, it is impossible to achieve all of those temperatures.

To get bedroom 2 at 24 C, the other rooms will be warmer than you want them to be - unless you open windows etc.

With TRVs you set each room to the desired temperature - full stop.

The point you appear not to appreciate with your CH system(with no TRVs) is that once your lounge is up to the temperature set by the room thermostat in that room, then the heating goes off. So the kids in bedroom 2 have a cold room.

To achieve the temperature you want in bedroom 2, the lounge and other rooms will be roasting!!

Conor_3

Cardew wrote: »

I appreciate that yours is a genuine query, and at times it is difficult to grasp the theory.

Take this situation.

I want the temperature in my living room to be, say, 22C.

I want my bathroom to be at 26C

Bedroom 1 to be at 18C

Bedroom 2 at 24C cos thats where my kids play on their PC in the evenings in their pyjamas.

Kitchen to be at 16C cos I am slaving over at hot stove!!

Hall to be at 16C cos it doesn't matter about that being warm.

Now if your heating is only controlled by a wall(room) thermostat in your living room or in your hall, it is impossible to achieve all of those temperatures.

<snip>

Yeah I get and understand all of that. My point is that the central heating boiler still has to be running to maintain the 26C in the bathroom despite all the other rooms being lower. In fact, the central heating would be running constantly for the time its set to be on as there's not one TCV thats connected to it to tell it the max temp has been achieved and to shut off - it will only shut off once the temperature on the boiler thermostat has been reached which has to be higher than that of the highest set TRV to assure that the required temperatures are reached. Is that correct?

So I can't see how you save money as they claim to do. In my mind, you're no better off other than having control over individual rooms - you're certainly not saving any money which is the what they're being marketed as doing.

albertross_2

It costs less to boil half a kettle of water, than a full kettle. If TRV's have shut off, there is only half a kettle.

mute_posting

Connor,

Imagine your radiator circuit as 2 pipes running in parallel with the boiler joining them at one end

The radiators then "straddle" these 2 pipes like the rungs of a ladder.

with TRV's as each radiator reaches temp and the valve closes, the water can no longer pass through so is forced to other rads until the valves on those close as they reach temp).

What you are left with is a very small ammount of water being that in the pipework and the rad without a TRV (as albertross says in #18, which "generally" is in the bathroom - as it is on the longest it keeps your towels nice and toasty), although I believe some systems alse divert to the hot water cylinder when all the rads are closed as an alternative to a rad without a TRV.

This small ammount of water gets to temp and the boiler shuts off

(Well that's how I've always understood it!)

HTH

MP

Cardew

Conor wrote: »

Yeah I get and understand all of that. My point is that the central heating boiler still has to be running to maintain the 26C in the bathroom despite all the other rooms being lower. In fact, the central heating would be running constantly for the time its set to be on as there's not one TCV thats connected to it to tell it the max temp has been achieved and to shut off - it will only shut off once the temperature on the boiler thermostat has been reached which has to be higher than that of the highest set TRV to assure that the required temperatures are reached. Is that correct?

So I can't see how you save money as they claim to do. In my mind, you're no better off other than having control over individual rooms - you're certainly not saving any money which is the what they're being marketed as doing.

The point is that to get the temperature in the bathroom to 26C, with your system, the temperature in all the other rooms will be above the temperature you require as you will have to turn up the setting on the wall thermostat in the lounge to achieve the required temperature in the bathroom.

Surely you can appreciate that shutting off a radiator will cause the system to use less gas? Well that is what a TRV does? It shuts off a radiator when the required temperature is reached.

If each radiator in a house with 8 radiators holds, say, a gallon of water and the pipework another gallon. When all radiators are on the CH boiler is circulating and heating 9 gallons.

If you have 5 radiators 'turned off' by TRVs(because the room is at the required temperature) then the boiler is only circulating and heating 4 gallons.