Energy myth-busting: Is it cheaper to have heating on all day?

Ultrasonic

Deleted_User said:

Towel rads, very nice to look at but do absolutely nothing to warm up a bathroom, yes they get extremely hot to touch, but offer no ambient temperature whatsoever.

This I completely disagree with as the towel radiator in my bathroom very effectively heats the room without issue. Being a decent size towel radiator in a modestly sized bathroom will help of course but a blanket dismissal is just wrong.

Astria

JohnSwift10 said:

I would rather the house heated up quicker and also the house feels more comfortable with a higher boiler temperature.

Don't forget that if you have a thermostat then the amount of swing in the temperature will be higher when the boiler temperature is lower. For example, on a cold day (eg, 3c or below) with the boiler set at 55c, the house may lose 0.5c between the time the thermostat kicks in and the house starts warming up again. So if you have it set at 20c, it may hit 19.5c before heating up again meaning the boiler will be on for longer to compensate. I tried turning down my boiler from 65c to 55c and it was just on longer, the amount of gas wasn't measurably different except for about 1 - 2% which could have quite easily been measuring error and reduced further if I had done more tests.

[Deleted User]

Sorry disagree,
BTU output is measured by heat generated NOT heat convected into a room such as a standard rad does.
There is less surface area on a towel rail compared to a traditional radiator, therefore less heat will be convected into the room.
More surface area = more heat= more convected heat.
This was the reason why standard rads were fitted with fins some years ago to help convect that heat from the large surface area.

You could also argue that it depends who you source your info from, many retail companies selling towel rails will surely try to compare both types as equally as good.
A decent plumber/heating installer will always advise that a standard rad is more efficient to run as it offers more heat into the room to.

My point is, dont expect to replace a standard rad with a towel rail of the same BTU and expect the same level of ambient heat in the room, it just won't happen !
You would need to increase the size and BTU of a towel rail significantly to try and obtain the same ambient room temp of a smaller standard rad, in turn using more gas and/or having your heating on for longer.

I appreciate though that the debate between towel rails & conventional rads is highly subjective.
For what it's worth, we replaced standard rads with towel rails in our bathroom and 2 ensuites, but purley for cosmetic reasons, we knew before changing them that the rooms would not be as warm.
We can get away with it in the ensuites as they are smaller rooms, but even with a very large towel rail in the bathroom the drop  ambient heat is very noticeable, even though you could not hold your hand on the towel rail when the heating is on.

Unfortunately my account on here is fairly new so I can't add links yet to my responses , that will clearly show that a towel rail is less efficient than a standard rad and the increase size and in BTU would have to be significant to try and get anywhere near a standard rad. 

The towel rail V standard rad debate will go on for a long long time. 

Northern_Wanderer

I don't know the physics behind this but I noticed that whilst my thermostat was set to 19.5C as usual, when the flow temp was at 55C, the stat seemed to be happy to keep room temp at 19C and not switch on boiler! So I'd have to up the room temp to get the warmth. Even when I set the temp to 20C it didn't start the boiler, only at 20.5 did it switch on boiler and then it gets too hot. For me, my system prefers to have a higher flow temp.

[Deleted User]

Yeah, if you tank/boiler is holding domestic heating water efficiently your stat will operate your heating pump to push the water to the rads around your home without the need to ignite the boiler.
Obviously after a while the temp will drop in the tank/boiler and when the stat calls the next time for heat your boiler will need to ignite again. 
Same applies to your hot water for bathing ect.
We have a fully pressurised system with a large holding tank, we can go a couple of days at least without having to ignite the boiler for hot water, as it's very well insulated.

Cardew

The vast majority of those who log in to this forum want to know the answer to question posed on page one of this thread ie,

Energy myth-busting: Is it cheaper to have heating on all day?

The last 20 pages of this thread will leave them totally confused; if they bothered reading that far. The answer is NO albeit there are 4,873 caveats to consider.

The next question to be posed is to ask if it is possible to jump from an aircraft at 18,000 ft without a parachute and survive. I contend the answer is NO but Nicholas Stephen Alkemade would not agree!

BUFF

Northern_Wanderer said:

I set my boiler temp to 55C, the next morning it took 2 hours to warm to 19.5C in the house. That doesn't please me so I tried 60C and it was 1.5 hours to get to temperature. I've set it to 65C but the weather has warmed up now both in the day and overnight so I can't really compare may daily gas readings at this point to see what savings there might be. I may try again in the autumn if I dare use my heating at all by that point.

I would say that whilst my upstairs temps are fine with lower flow temp, my downstairs is struggling meaning I'd have to up the room thermostat which would seem to be counterproductive.

It's quite possible that your radiators aren't adequately sized to efficiently heat the rooms at lower flow temperatures (many people simply replacing boilers on an old system that was designed for 80/60 running will find this).

richardc1983

QrizB said:

Deleted_User said:

Towel rads, very nice to look at but do absolutely nothing to warm up a bathroom, yes they get extremely hot to touch, but offer no ambient temperature whatsoever.
If you have towel rails in bathrooms with stats fitted it will be a waste of time.
Towel rails are only good for 2 things, warm/dry your towels and they look nice.

Towel rails have a rated heat output, just like a radiator does, and measured/calculated in exactly the same way.

Here is an 1818BTU, 533W radiator:
https://www.screwfix.com/p/kudox-premium-type-21-double-panel-plus-single-convector-radiator-600-x-400mm-white-1818btu/46858

And here is an 1889BTU, 554W towel rail:
https://www.screwfix.com/p/blyss-towel-radiator-1600-x-600mm-chrome-1889btu/2238v

The towel rail will heat your bathroom just as effectively* as the radiator will.

* Output may be reduced if you actually hang towels on it, of course!

We got rid of our towel rail and fitted a tall column rad as the towel rail wasnt enough to warm the room. New column rad is 1.8kw at 50c flow temp and we fitted a trv to stop it getting too warm. 500w for a towel rail does nothing in our bathroom. 

Petriix

Cardew said:

The vast majority of those who log in to this forum want to know the answer to question posed on page one of this thread ie,

Energy myth-busting: Is it cheaper to have heating on all day?

The last 20 pages of this thread will leave them totally confused; if they bothered reading that far. The answer is NO albeit there are 4,873 caveats to consider.

The next question to be posed is to ask if it is possible to jump from an aircraft at 18,000 ft without a parachute and survive. I contend the answer is NO but Nicholas Stephen Alkemade would not agree!

It's amazing how many people think that caveats and their own specific circumstances can somehow defeat the fundamental laws of thermodynamics.

No. If you add more heat to your property then it has more heat to lose and objectively (and obviously) will lose more heat.

No. Your anecdotal evidence of how much energy you think you are using is not relevant. There are too many variables to make any kind of judgement based on personal usage. I've used 25% less gas this year than last without changing anything. By some of the logic on here I could argue that buying blue socks has reduced my consumption.

BUFF

Deleted_User said:

There's lots to consider, and in my opinion the answer is not as straightforward as just leaving your heating system tick over day in day out.

correct, it's going to be different for every house/system & person (convenience/comfort are usually considerations as well as simply lowest running cost).

Deleted_User said:

For instance where is your ground floor room stat installed, many homes have them installed in the hallway which might be the coldest part of the house, therefore the stat is constantly switching on your boiler to heat up the whole of the house even though it's only the hallway that might be the coldest, so if you have no rad stats fitted in your rooms you will be burning gas for the fun of it trying to heat up the hallway which might not even have a rad there, so the stat will be asking the boiler for heat but it might take forever for the stat to benefit from the heat.

Correct room stat location is very important, for an efficient heating system to work correctly.

Yes, but if you know your system you learn how to offset. e.g. my roomstat is in the kitchen which is the coldest room in the house - setting the roomstat to 14.5 there will get me 16C in the rooms.

Deleted_User said:

Towel rads, very nice to look at but do absolutely nothing to warm up a bathroom, yes they get extremely hot to touch, but offer no ambient temperature whatsoever.
If you have towel rails in bathrooms with stats fitted it will be a waste of time.
Towel rails are only good for 2 things, warm/dry your towels and they look nice.

Sorry but I totally disagree with this. My 1800h x550w white ladder rail is rated for ~3000btu & the bathroom can be the hottest room in the house.
Metallic plating or towels over (rather than in front of) will reduce output significantly.
Because I run lowish flow temps mine doesn't get extremely hot to touch - hot, yes, but not extremely.