Posted By: WillInAberdeen*another* jumper.

An internal partition wall or intermediate floor with acoustic wool in it, has a U-value about 0.5, which is well able to maintain a temperature difference of say 3 degrees between say a lounge and a bedroom, given that the external walls can maintain a difference of up to 25deg from inside to outside.

I like a bedroom to be say 21deg in the evening, maybe 15-17deg overnight, and about 19deg when I wake up. I like a lounge to be unheated overnight and through the day, and perhaps 21deg in the evening. By tweaking the timing of the different zones, I can just about do this, but it needs luck and lots of tweaking. Shouldn't be difficult for controllers to just do this, don't know why they don't. Most cars can organise different temperatures for the driver and passenger.

That doesn't reflect the experience of my house. We're small and tall, with ground plus two floors above. Low temperature UFH throughout. We've have all the bedroom loops turned off and just heat the bathrooms on the upper floors and we see very little temperature differential. In the coldest part of winter we probably do see a couple of degrees cooler in the bedrooms but through most of the heating season those rooms must get enough from convection/conduction and solar gains that they're no different. Equally with UFH in a concrete floor (and the flow temperatures we need to heat) you just don't see the sort of changes you're talking about.

For internal temps to drop to from normal 20/21 to 15 would take a good few days (I'm pretty sure when we were away for a couple of weeks in winter with the heating off it was still about 15C in the house when we got back).

Simon, exactly, if you have heated concrete floors then your house will have a more stable temperature, so it will be more difficult for a controller to set up a daily temperature profile, if you wanted that. The heated concrete keeps the lower rooms warm overnight - the upper rooms' temperatures can diverge from downstairs, but by (only) a few degrees, as you mentioned. Do the walls also have much mass inside the insulation envelope?

As per previous page, convection is going to move heat depending on whether doors are typically open/closed and whether the bedroom and living room temperatures are linked by a shared MHRV. As you mentioned, a 3-storey house will naturally have more convection. Do you have self closing firedoors off the stairwell because of the 3rd storey? We close all our stairwell doors but only at night.

The heating controller can only control different temperature profiles during the heating season (winter), the rest of the year the temperature is controlled more by solar and ventilation.

Edit: Were I starting from scratch (I'm not) I think I would put the bedrooms together in one wing on ground and upper floors, facing North with insulated timber floors, thermally separate from the living rooms, that was good in our previous house. That house was IWI'd granite with a plasterboard/PIR/timber first-floor-in-the-roof, so the thermal mass was disconnected from the rooms. Our current house/project has the bedrooms mainly above the kitchen/dining and utility rooms (another funny shape).

Posted By: WillInAberdeenSome people like stable temperature, others like control, it should be possible to design efficient housing for both.

The point is that it is exactly the 'thermal mass' of a building, storing heat for a long time, that makes it possible to build efficient housing in the first place. If you don't store the solar gains, you have to provide the heat actively and thus inefficiently.

It's also not possible to build different types of houses for people who want control versus people who want stability since one would hope that the building will have more than one set of occupants during its lifetime, typically many more. Unless of course you propose segregated housing for people who want fine control over individual room temperatures.

Frankly I have trouble believing anybody who says they need their bedroom at say 17°C to sleep. Do they do that with just a sheet over them? And if not, why can't they allow a warmer temperature and reduce the coverings? I think it's a learned prejudice that can be unlearned.

Posted By: djhFrankly I have trouble believing anybody who says they need their bedroom at say 17°C to sleep. … I think it's a learned prejudice that can be unlearned.

I agree. I suspect it's because people want fresh air in the bedroom and associate that with being a bit chillier than they'd put up with in the rest of the house. Of course, with MVHR…

Posted By: Ed Davies

Posted By: djhFrankly I have trouble believing anybody who says they need their bedroom at say 17°C to sleep. … I think it's a learned prejudice that can be unlearned.

I agree. I suspect it's because people want fresh air in the bedroom and associate that with being a bit chillier than they'd put up with in the rest of the house. Of course, with MVHR…

No, it's the other way round, your circadian clock is naturally set by both light and temperature cycles. You might have trained yourself to sleep with the lights on or in constant temperature environments, but I think that is unwise, it's not how our biology is supposed to work. It's more of an issue up North as we have short daylight in the winter, some colleagues have to sit in front of SAD lamps.

If you are experiencing trouble with beliefs, or have some prejudices you wish to unlearn, a brief Google will help you out, eg
https://www.nature.com/articles/nature25740
”Abstract
Circadian clocks coordinate behaviour, physiology and metabolism with Earth’s diurnal cycle1,2. These clocks entrain to both light and temperature cycles3, and daily environmental temperature oscillations probably contribute to human sleep patterns4”

Or https://sleepcouncil.org.uk/advice-support/sleep-advice/7-steps-to-a-better-nights-sleep/
"1. Your Bedroom... We recommend a cool temperature of around 16-18° C "

Possibly the issue is that most people don't buy a house based on heating controls, whereas they will base choices on number of bedrooms or architectural style. A bit like level of insulation doesn't really seem to translate into sale prices or desirability, for the majority of the market.

Posted By: WillInAberdeenNo, it's the other way round, your circadian clock is naturally set by both light and temperature cycles. You might have trained yourself to sleep with the lights on or in constant temperature environments, but I think that is unwise, it's not how our biology is supposed to work. It's more of an issue up North as we have short daylight in the winter, some colleagues have to sit in front of SAD lamps.

If you are experiencing trouble with beliefs, or have some prejudices you wish to unlearn, a brief Google will help you out, eg
https://www.nature.com/articles/nature25740
”Abstract
Circadian clocks coordinate behaviour, physiology and metabolism with Earth’s diurnal cycle1,2. These clocks entrain to both light and temperature cycles3, and daily environmental temperature oscillations probably contribute to human sleep patterns”

Sadly, the article is behind a paywall so we're reliant on the abstract being accurate. But the text immediately after your quote goes on:

"However, the neural mechanisms through which circadian clocks monitor environmental temperature and modulate behaviour remain poorly understood. Here we elucidate how the circadian clock neuron network of Drosophila melanogaster processes changes in environmental temperature."

So there's no evidence about human sleep here.

Or https://sleepcouncil.org.uk/advice-support/sleep-advice/7-steps-to-a-better-nights-sleep/
"1. Your Bedroom... We recommend a cool temperature of around 16-18° C "

Yes, this is typical of the kind of advice I think is misguided. Again no evidence and they do say "(We would like to stress that we are not experts or specialists in the fields of sleep disorders or insomnia.)".

I could also quote https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2034754/
"Ambient temperature exerts a prominent influence on sleep. In rats and humans, low ambient temperatures generally impair sleep, whereas higher temperatures tend to promote sleep." But again this article is about a different species, in this case mice. I could say that I do know the one thing that most commonly keeps me awake is if my feet are cold. But that's just anecotal.

One could look at descriptions of the thermoneutral zone such as https://www.fbscience.com/Elite/articles/10.2741/518 which describe it as being between 28°C and 32°C and outside of which the body changes its metabolism to cope. Personally I find much over 26°C is uncomfortable. Where I'm sitting at the moment is about 25°C, which is comfortable whilst I'm not doing much. My skin temperature under my clothes is 33°C to 35°C.

So I think the most important bit is that the subject remains poorly understood. And I still haven't seen anything that tells me how my biology is supposed to work.

As regards the effect of light, that seems to vary. When I was younger, I couldn't sleep if there was a crack of light showing through the curtains. Nowadays I'm not particularly bothered. My wife has undergone a reverse journey so we do still sleep with the blinds closed.