Battle of the thermostat: The science behind your central heating arguments.

[ericmark]

The BBC write up is interesting. there are a number of statements, which I have found myself.

But once you're fast asleep, a cool room temperature is ideal: between 16-18C

yes I want it cooler when in bed.

Regulations suggest this should be 16C (60F) or 13C (55F) if the work involves "rigorous physical effort".

But some people work outside, I assume this refers to continuous without a place to warm up again. For Diabetes

Even slightly cooler homes at 18C (65F) can lead to hypothermia.

Oh must be careful wife is diabetic.

At night, I like it to cool down, and would agree 16 - 18ºC and in the day 18ºC is ample, but in the evening more like 20 to 22ºC. But I find to walk into a room for a short time, like to make coffee, 18ºC is still ample.

However, the main point, is I that don't want a constant temperature, and so use programmable TRV's, but the idea of electric heating is to keep a constant temperature in all rooms all thought the day. Just can't see how that would ever work?

 

[drives]

However, the main point, is I that don't want a constant temperature, and so use programmable TRV's, but the idea of electric heating is to keep a constant temperature in all rooms all thought the day. Just can't see how that would ever work?

You can do set backs for certain periods i.e. during the night. Wouldn't want this any more than a couple of degrees C though- our controls actually have a 'cool nights' option which is basically the same thing. Other option (which we have) are retention of TRVs in the bedrooms. General recommendations seem to be that use of TRVs should be limited with ASHPs so we've removed them in all other rooms/bathrooms etc. Works fine, albeit we don't have a massive differential so TRVs set at 20 o bedrooms don't get too hot/overshoot, and house set at 20.5 (generally hovers around 21 though).

We don't use winter duvets any more though and sometimes when zero outside I'll be in bed just using a bed sheet as a duvet as it's quite warm. I don't mind this though, personally. Much nicer than getting up in the middle of the night for pee in a freezing cold house with a setback of 15/16. Could never go back to that.

 

[ericmark]

I note the report on room temperature. It shows living room top, which gets the sun, and wife's bedroom bottom, which gets very little sun. More interested in the speed at which temperature drops, 19.5ºC to 18ºC from 3 am to 7:30 am, around 1/3 of a degree per hour.

So 8 hours sleep, and drop around 2.5ºC. So setting a thermostat 20ºC in the day and 16ºC overnight, only with very cold nights would the central heating cut in.

Bedroom heated reasonably fast at 1ºC per hour, but living room, at 0.5ºC an hour, need to start heating way before we want the room.

The problem is likely the TRV heads had not opened the valve fully, I know we should control the room with TRV heads, but if I want living room at 20ºC I tend to set TRV heads to 22ºC and let the wall thermostat control the room.

My battle of the thermostats is more to do with wall thermostat v TRV head. I have three rooms where if too cold, it will start boiler, hall, living room, and wife's bedroom. In the rest of the rooms, it relies on boiler being running for the TRV to warm the room when required.

Theory is great, fit Drayton Wiser TRV heads in every room, and all will be perfect. But I already have 9 programmable TRV heads, plus the one linked programmable TRV head (Wiser) so seems very little to be gained, changing programmable heads for linked programmable heads.

 

[Mister Banks]

Replacing all your existing TRV’s with Wiser TRV’s will be an improvement on what you have now but at a cost. I’m not a fan of micro zoning and have replaced most of my Wiser TRV’s with manual TRV’s to act as temperature limiters.

I think you have two distinct areas heated from a single heat source so have you thought about treating them as individual zones with TRV’s on all radiators managed by two room thermostats? Comes at a large cost though!

 

[ericmark]

you thought about treating them as individual zones with TRV’s on all radiators managed by two room thermostats?

Yes done that, the flat under the house is one zone, and main house another zone. Most of the winter, the flat is not used, so turning off a group of 4 rooms works well. In the main house, three rooms intermittent use, dinning room, craft room, and office. Not heating them requires the doors to be closed, and we moved from an open-plan house, so getting the wife to close doors is hard going.

So rather than turn off rooms not in use, turning the heating down is better, so one does not take too long to heat when wanted, and two if the door left open not a huge amount of cold air comes into the house.

Replacing all your existing TRV’s with Wiser TRV’s will be an improvement on what you have now but at a cost. I’m not a fan of micro zoning and have replaced most of my Wiser TRV’s with manual TRV’s to act as temperature limiters.

I can't see why? The Wiser TRV will work as a temperature limiter, my existing TRV heads 5 x eQ-3, 3 x Energenie, 1 x Kasa, all act as programmable temperature limiters, the Wiser Thermostat and TRV head, plus the Nest Thermostat can start up the boiler. The eQ-3 are only blue tooth, and will only connect to one phone, but work well, they don't show current, only target, the Energenie and Kasa as with Wiser show target and current, and work with internet. One Energenie was smashed and was replaced with the Kasa, we were told Energenie worked with Nest, they don't, so when one smashed, replaced it with Kasa, which to be fair is a lot better.

At £40 a pop, all Wiser too expensive, and can't see how there would be any gain. But no assess to pipework except at the boiler, or at radiator, so adding further zone valves is a non-starter.

 

[Mister Banks]

The improvement would be having all the TRV's managed from a single app rather than multiple apps and access methods but, as I said, this comes at a £ cost which isn't going to be small. I don't like multiple thermostats having the ability to start the heat source potentially just for one room, its a waste of energy due to short cycling of the boiler.

A Wiser TRV used as a temperature limiter is a waste when a £15 manual TRV will do the same job and there are no batteries required.

As with most things its all about trial and error on your particular system to get to a position where you are happy with the compromise between heating comfort and cost.

 

[ericmark]

As we most things its all about trial and error on your particular system to get to a position where you are happy with the compromise between heating comfort and cost.

Very well put, at £15 each for the eQ-3 in 2019 to pay £15 for a temperature only version seems daft. As to batteries, the Kasa does seem to eat them, but the rest a year seems to be the norm, so worth the expense.