Where?
Link?
Anything tangible or just hot air ?

Worth viewing in the context of the ideological decisions that are currently working to stop the proposed public information campaign:

https://www.theguardian.com/politics/2022/oct/07/climate-minister-britons-not-be-told-use-less-energy-winter-nanny-state

I'm sure this has been discussed ad nauseum, but it drives me a little nuts to see advice saying "turn down your thermostat by ONE degree and save x%!"

Personally I'd prefer the advice to be "No able-bodied person ever died of a house at 16 degrees (and frankly a fair bit cooler than that). Try it. You'll get used to it, and save a fortune."

Am I wrong? My sense is that the many people that keep their home at 22 degrees will turn in down to 21 and think they're saving the world.

I can understand that the elderly or otherwise vulnerable probably shouldn't risk low temperatures. And some homes risk excess condensation and mould growth at lower temperatures.

But I'm fairly sure that many others (you won't be surprised to hear my own included) can be really quite comfortable at 16 degrees or below. It's surely not in the same ballpark as living in an unheated home, health and comfort wise, as many did a generation or so ago. Certainly trialling it for a few weeks should be a worthwhile exercise for many.

A neighbour was considering the percentage reduction in his household emissions he hoped to achieve by installing a heatpump. I couldn't help but think he would achieve as much, if not more, at zero cost and without the disruption and embedded carbon, simply by trying to live in a slightly cooler home.

talking of energy saving my attempt to save energy cost went down the pan today.
PV immersion dump broke last week , so I suggested putting the immersion on when the smart meter was reading over 3kW produced and it was likely to be clear and sunny for a bit, then turn it off after an hour or so.
got home this evening to find we'd used £4.50 odd of electricity today rather than the usually 80p
someone forgot to turn it off

We are talking about behaviour change, with it there is no longer a problem. An awful lot of people seem to think that heating is a basic human right, when it isn’t. I like this discussion, thanks folk.

What is this dial your talking about turning down from 22 to 21. At this house if its cold just throw another log on the fire. Only time this house hit 21 this year was during the heatwave and I really did find it to hot for confortable sleeping.

If people live somewhere with say 2000 heating degree days, then reducing their heating by 1⁰C over a heating season of say 150 days for 18 hours per day, represents a saving of 150*18/24 / 2000 = 5% on heating, though not on DHW.

Most people have their thermostat in whichever room heats up slowest, and TRVs in all the rest. Turning down the thermostat 1⁰ without also turning down the TRVs, is not going to cool the whole house, so will not reduce heat losses as much as expected.

Guy on the radio today was advising people to turn down their boiler flow temperature from 80⁰ to 60⁰ to get it condensing. I had been wondering why nobody was pushing that one, which seems like an all-gain-no-pain thing to do.



Switching to an air source heat pump reduces their heating and DHW in proportion to CoP, so typically saving >70% of energy usage. Cost savings about nil if they are switching from price-capped gas to electric. Additional carbon savings in line with the carbon intensity of electricity vs gas, so carbon savings now around 80% and rising - like turning the stat down by 16⁰ !

Hi Rob, the normal HDD base for a poorly insulated home is often taken as 15.5⁰C (= 60F) and for a well insulated home it might be 10⁰C or less - think of it as the outside air temperature at which you'd first turn the heating on - eg I'm sure you wouldn't turn the heating on when it's 19⁰ outdoors!

The difference between the base temperature (eg 15.5⁰) and the indoor temperature (eg 21⁰) is provided by the incidental and solar heat gains.

For a base temperature of 15.5⁰, degreedays.net quotes 1890 HDD at Stansted for the past year, and 2400 at Aberdeen, or 2200 at 14.5 (8% less).

But that's not the whole story, because even if it's below 15.5⁰, most people won't heat their house 24 hours each day. Only for the hours when they are awake, which tend to be the warmer hours of the day. So although heat is lost for all 24 hours, the thermostat is only activated for fewer hours each day (the say 18hours X say 150 days in my example, just a guess). So the effects of adjusting the thermostat setting are correspondingly less.

To be fair, HDD is not a very reliable science afaict, because relatively small local changes in weather can swing the results a long way. We lived up on a hill, within sight of an airport a few miles away nearer the coast, which is the local met station. We were regularly 2 or 3 degrees cooler overnight than their reading, which added up to a lot of HDD!

Probably there are much better ways to estimate the benefits of turning the stat down by 1⁰ - but however it's done, it's not going to be a transformational amount, which was Gareth's point! Interesting to think about tho!


(Edit to add: obviously the answer will be different for different houses, locations, occupants)

I like it cooler when I am asleep, 15 or 16⁰ is good, I can't sleep as well when it's warmer. Then 17 or 18⁰ when I am awake and active, or 19⁰ if I am sat down a long time in front of computer or TV.

I think all houses should have those programmable stats with different temperatures for different times of day (assuming low enough thermal mass to allow control). Another reason why 'turn your stat down 1⁰' is poor advice.

Posted By: GarethCWe have guests arriving tomorrow.

Excellent idea. A good sized guest is about 100W!

Posted By: GarethCI'm sure this has been discussed ad nauseum, but it drives me a little nuts to see advice saying "turn down your thermostat by ONE degree and save x%!"

Personally I'd prefer the advice to be "No able-bodied person ever died of a house at 16 degrees (and frankly a fair bit cooler than that). Try it. You'll get used to it, and save a fortune."

Am I wrong? My sense is that the many people that keep their home at 22 degrees will turn in down to 21 and think they're saving the world.

I'm not sure 16 degrees is recommended under government guidelines, especially for the inactive elderly.

Having crashed the economy, disrupted the eduction of 1000's of children, and hectored people to get needlessly vaxxed over the last 2 years in order to save a few 80 year olds from a novel virus we're now going to abandon them to the cold? That makes sense.

To be fair I find heat is subjective - 18 degrees maintained by an electric convection heater feels much more comfortable to me than 18 degrees ambient at the end of summer.

Personally I don't know why people want 20 - 22 degrees in a room, 18 - 19 degrees is fine for me. I think I might invest in some long johns but I'm not sure how I'm going to get my skinny jeans over the top

I find that what is comfortable depends greatly on the type of heat. In my view convected heat is not very effective at actual warming, and becomes stuffy before it feels hot. Radiant heat is what gets through to me. A blazing open fire feels nice and hot even if the air temperature is low.
People can feel warm standing round a brazier or a bonfire even if the air temperature is sub-zero. It's the direct impact of radiant heat on bare face or hands that counts.

It's also self-regulating. Someone who has joined the company and comes in stamping snow off their feet can stand in front of the fire and get warm in minutes. Others regulate their distance from the fire as they wish.

The idea that 21 or 20 or 16 is the appropriate temperature for the whole house and all its occupants seems absurd to me.

Conducted heat does have a role. That's the point of basking in a comfortable bath in water almost as hot as one can bear.

<blockquote><cite>Posted By: Cliff Pope</cite>

The idea that 21 or 20 or 16 is the appropriate temperature for the whole house and all its occupants seems absurd to me.
</blockquote>

Interesting points about type of heat. Not sure I'd agree with this point though. While some might need more layers to be comfortable at 16 degrees than others, I do think it is almost universally possible (with a few exceptions) for people to be comfortable at this temperature. It's cool, but not cold.

Posted By: wookeyall internal surfaces are >14C and there are no significant draughts. i.e essentially 'what the passivehouse people said'.

I think the PH rules on glazing are designed to keep all inward glazed surfaces above 17°C at the design interior temperature of 20°C in the belief (which I have no reason to dispute) that limiting temperature differences to 3°C prevents convection cycles setting up.

So if the corners of your windows are 14°C and there are no draughts it would seem to imply either the internal temperature is no more than 17°C or you have no large windows (specifically no tallish ones)

FWIW our internal temperature at the moment is 23°C (no heating of course) and we're quite comfortable.