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oh dear 😉At 13C the differential between the thermostat and outdoor temps is 4C, at -3C it’s 20C, so five times the heat loss
oh dear
Go on?
I did what’s been mentioned above, but with an Arduino. I measured the time the boiler was on with a microphone. It displayed how long it was on for each 24 hours.
I'm going to do this. I've got an spare Pi that's sat in a drawer (bit old but hopefully will work) and will grab a cheap USB microphone.
Hopefully I can get it to measure the sound level and when it goes above a certain level it will send a message to IFTTT which will add a row to a spreadsheet.
I'll then create a little app to gather that data and make it look pretty on my phone.
At 13C the differential between the thermostat and outdoor temps is 4C, at -3C it’s 20C, so five times the heat loss
is rate of heat loss linear with deltaT? I'd be suprised.
is rate of heat loss linear with deltaT? I’d be suprised.
Yes. The U value of insulation is a constant measured in Wm2/K where K is the differential; and m2 is the area of the insulation which is also fixed in this context so if K goes up then W heat loss has to go up proportionally.
Of course it's not that simple as always in the case of my house - the boiler has to put heat into all the rooms and they are all differently insulated because they have different window area and some of them border next door.
just wondering whether anyone had bought one of these yet..
^^ no, but it's an interesting idea.
is rate of heat loss linear with deltaT? I’d be suprised.
scientifically, not exactly but over the miniscule actual range of temperatures we're talking about compared to 'all the temperatures' where different processes would then become relevant, it's basically correct.
Newton's law of cooling states that the rate of heat loss of a body is proportional to the difference in temperatures between the body and its surroundings. As such, it is equivalent to a statement that the heat transfer coefficient, which mediates between heat losses and temperature differences, is a constant. This condition is generally true in thermal conduction (where it is guaranteed by Fourier's law), but it is often only approximately true in conditions of convective heat transfer, where a number of physical processes make effective heat transfer coefficients somewhat dependent on temperature differences. Finally, in the case of heat transfer by thermal radiation, Newton's law of cooling is not true.
Shiney surfaces reflect your own ir signature back at you. So you stand in front of the silver foil insulation and think itz hot. Its not, its your body heat being bounced off it and back at ya.. Possibly
Hmm. Wrap too tight?
How would you wrap the pipe so the tape is airtight where it overlaps I’d it’s not tight? Imagine taping a drop bar with the tape loose?
My application looks a lot like the manufacturers website https://ybsinsulation.com/diy-products-application/reflective-pipe-wrap-insulation-diy-product/
is rate of heat loss linear with deltaT? I’d be suprised.
Consider yourself surprised.
The only changes would be if you changed the mechanics by which the heat was transferred. e.g.
Gas - solid wall - gas, would have one rate of transfer
Condensing vapor onto the inside wall (aka condensation because you house is damp)- the same solid wall - boiling liquid on the other side (aka saturated brickwork exposed to wind), would have another.
So you could argue that rain and humidity affect it and those are related to temperature, as would snow or frost, but it's still linear with temperature when everything else is the same. You're probably considering single figure percentage changes for an average cavity wall insulated house in average weather, compared to Molgrips 500% figure.
It's also why lowering your thermostat by 1C makes a claimed 10-15% difference to the bill, because the average outside temp is probably ~10C and the average thermostat set point is ~19C, so 1C is that 10-15%.
You’re probably considering single figure percentage changes for an average cavity wall insulated house in average weather, compared to Molgrips 500% figure.
Show your working?
I meant to point out that going between the extremes of temperatures where I live has a huge effect on gas consumption for heating.
The heating just popped on for the first time since 7am, and only for about 5-7 mins. Compared to how long it was burning this time last week my figures seem like they are in the ballpark.
Change of subject - anyone tried a terracotta pot candle heater? Internet suggests that a candle produces about 80W and an idle human 100W or so. I reckon people in a room have a noticeable effect on the temperature so I might try it. Probably not cost effective nor ideal in terms of air quality...
If the 80W figure is accurate and the 3hr burn time for a tealight is accurate then tea light heating is abot 20p/kWh which is about half that of an electric heater in my house.
Change of subject – anyone tried a terracotta pot candle heater?
Sometimes they explode.
Have done it outside in the garden when it cools down in the evening, wouldn't do it inside.
I would get a big pot I think, that should help keep the temps down.
How would you wrap the pipe so the tape is airtight where it overlaps I’d it’s not tight? Imagine taping a drop bar with the tape loose?
You can't
But you'll find their claim to be equivalent to loads of rockwool to be only under certain air gap constraints - it's buried on their site.
How would you wrap the pipe so the tape is airtight where it overlaps I’d it’s not tight? Imagine taping a drop bar with the tape loose?
You can't
But you'll find their claim to be equivalent to loads of rockwool to be only under certain air gap constraints - it's buried on their site.
https://www.greenbuildingadvisor.com/article/stay-away-from-foil-faced-bubble-wrap
Re the pipe lagging, you can get lagging strips of felt or similar, given that situation I'd have wrapped in the felt first then the tape on the outside.
@trail_rat that person was clearly taking the piss.
Also, for the record, I did not hear about this on TikTok. I probably heard about it 25 years ago.
@trail_rat that person was clearly taking the piss
I believe the correct defence here is
Show your working ?
14 tea lights in that picture. Ok, some may have been used to prop up the pot, as in some designs, but that one appears to have been supported by the central rod. So it could have got very hot indeed. If I were to do it I'd use a large pot and a single tea light.
However, This has got me thinking that there's got to be a much better way to re-emit the heat from a tea light or three. But what is more effective than just letting the candles burn anyway? Sure, the heat goes to the top of the room, but it would still basically do that anyway.
This has got me thinking that there’s got to be a much better way to re-emit the heat from a tea light or three
heat a chamber of water, and then pump it around to other chambers of water where you want the heat...
Huh all my comments were related to foil bubble wrap ....
Is the forum not letting me post an answer because maths ends up looking like code?
I just get error 403
jam-bo, great idea but it'll never catch-on...
But what is more effective than just letting the candles burn anyway?
It's almost all convective heat which is subject to a high degree of transportation to the top of the room. The purpose of the pots is to convert at least a portion into radiant heat which is not subject to the effects of convection and will be felt more readily at the level of the pot - i.e. where people are.
The problem with radiant heat sources is for it to extend a distance from the source you need higher temperatures, hence the exploding pots.
My thermostat is an old bimetallic strip affair, which seems to have a degree of error.
Is the a digital version that isn't eyewateringly expensive or needs a monthly payment. Looking for something that might have less of a range for click on click off.
Change of subject – anyone tried a terracotta pot candle heater?
A friend is heating his office with them this winter....
[url= https://live.staticflickr.com/65535/52575431481_e88f67d1b5_c.jp g" target="_blank">https://live.staticflickr.com/65535/52575431481_e88f67d1b5_c.jp g"/> [/img][/url][url= https://flic.kr/p/2o6UQ5z ]Tea light heater[/url] by [url= https://www.flickr.com/photos/brf/ ]Ben Freeman[/url], on Flickr
My thermostat is an old bimetallic strip affair, which seems to have a degree of error.
Is the a digital version that isn’t eyewateringly expensive
There is, yes. We have one and it's very useful as you can set the gap between of and on, and you can move it around closer to or further from the rad in that room to fine tune the response. The wall box just replaces the existing stat wire-for-wire.
Ours is like this:
https://www.heatingcontrolsonline.co.uk/horstmann-hrfs1-programmable-wireless-thermostat.html
Re lagging, I have figured out that the reason the kitchen rad is always the coolest one is that the pipes cross the kitchen in the ceiling void in the same section as the extractor fan duct which is known to be shit and there's an open vent at one end. I haven't taken it off to look but I suspect the pipe from the cooker hood just goes straight into the ceiling void and there's a grille at the other end to the outside.
Re tealight terracotta heaters:
https://www.bbc.co.uk/news/uk-england-derbyshire-63880157
Edit
Sorry, just realised that that BBC article is already posted further up this page.
Wiki suggests 32W per tealight.
Google suggests £5 for 100 is the going rate.
So 3.2KW of energy for £5.
Doesn’t seem that cheap even before you burn your house down…
So having had a few rads refusing to heat up downstairs we got a guy in to do a powerflush today.
While the pump was running got all of the rads nice and hot, flushed out loads of crap and refilled with clean water expecting it to sort the problem.
Back on to the normal pump and the same rads are still not getting off cold.
The powerflush didn't bypass any valves so we can rule that out.
Shouldn't be any muck left in the system either.
Pipes either side of the pump are very hot and the pump is whirring away like a good 'un and was cleaned out during the flush and found to be in good working order.
Rads were working fine last Spring and didnt't notice anything over summer, but why would you. Heat in downstairs rads didn't stop overnight, they got gradually worse over a month or so when we started using heating more in Autumn.
All upstairs rads getting nice and hot and if we lock them all down it still isn't getting the downstairs ones any warmer.
Short of taking all of the floors up ( a little difficult with a wheelchair user in the house) does anyone have any thoughts on what else it could be.
Wheres the boiler?
Is it system or combi ( no hot water tank)?
Airlock somewhere when it was refilled.
Boiler downstairs in Kitchen, pump in airing cupboard upstairs, boiler is heat only. HW tank in loft.
HW all fine, rads upstairs all fine.
System all bled after refill and it's doing exactly the same thing as it was doing before.
If we have to lift the floors we have to find accessible accommodation for our daughter and her care team so any insights would be greatly appreciated.
Wiki suggests 32W per tealight.
I read 80.
@smokey_jo I think your pipes are fine if the powerflush worked. Have you tried increasing the pump flow/pressure? I would speak to a plumber if I were you and ask what your options are.
Pump is on max and according to the plumber able to pump a higher flow than a standard household pump. He said the powerflush was pushing around 4-5 times the flow though so would be more easily able to overcome anything partially blocking pipework.
It's looking like a floors up job
we have had similar in this cold spell, unfortunately the last rad on the loop is the living room one which is the one we'd like to get hot in preference, and it will eventually. But the others are calling for heat to get the TRV's up to temp first so the hot water keeps going through them and by the time it gets to the living room it's not hot enough to make a significant difference.
So I have to turn the bedroom ones down through the day to overcome that, and then reverse them and save the living room one in the morning. Except not now we're all off work and college and want the living room warm all day, not just evening.
Which leads neatly to the blog my ex-colleague writes, I linked previously about his (mainly successful) attempt to effectively go off grid using heat pumps, solar and battery storage but his blog yesterday was all about whether keeping the house warm overnight is economical vs letting it cool and then heating it more to get back to temp.
https://protonsforbreakfast.wordpress.com/2022/12/19/setback-should-you-lower-heating-overnight/
Ok, that helps somewhat.
So you have a system boiler in the kitchen, and a traditional, indirect hot water tank, heated by the boiler, upstairs in an airing cupboard.
This is strange though ax its the reverse of what you would expect, hot rads downstairs and colder upstairs.
This is the limit of my knowledge of S and Y heating layouts but hopefully Bear will be able to come up with an answer.
I think the pipework from the boiler heads straight to the upstairs airing cupboard which would explain hot rads upstairs. I think the downstairs rads are after the upstairs ones on the circuit.
If I lock all of the upstairs ones off it still doesn't the downstairs ones off cold though
Ok, by the power of googlefu i am now au fait with S and Y dhw systems.
I think your diverting valve might be issue here.
Although the pump is over specified for the task there is not enough flow or, and pressure to pump a decent rate round the system, but the power flush did.
So the hot ch fluid from the boiler is not making its way round the house sufficiently fast enough to heat the last, lower rads downstairs.
Habe you tried turnimg all the upstairs off at the locksheilds, not the trvs, amd, if you have one, shut off the hot water tamk inlet valve.
Then open fully the locksheilds and trvs downstairs
Be a fun 40 mins in your house this evening
Habe you tried turnimg all the upstairs off at the locksheilds, not the trvs, amd, if you have one, shut off the hot water tamk inlet valve.
Yup we tried that and nothing - not a sausage
It wasn't as fun as you make out it might have been though
I think the pipework from the boiler heads straight to the upstairs airing cupboard which would explain hot rads upstairs. I think the downstairs rads are after the upstairs ones on the circuit.
This is the case in our house, the downstairs rads get less warm even if the system is balanced due to a longer unlagged pipe run. But they still do get warm.
But the others are calling for heat to get the TRV’s up to temp first so the hot water keeps going through them and by the time it gets to the living room it’s not hot enough to make a significant difference.
The rads aren't in series.
Pump is knackered then.
If you manually shut off everything upstairs then no hot rads downstairs at all.
Did you check the return pipework temperature at the time?
Has it worked in the past?
What does the pump sound like? Bubbles or smooth hum?
Have you checked the bubble traps are working?