Not putting the heating on – how’s it going…?

That’s right, if it wasn’t for the failed attempts using different microphones that didn’t work, and the switch that I couldn’t fit to anything suitable, and the hours of my time writing the software.

Practically nothing really!

That’s right, if it wasn’t for the failed attempts using different microphones that didn’t work, and the switch that I couldn’t fit to anything suitable, and the hours of my time writing the software.

Practically nothing really!

I mean, you’ve probably just described 99% of original Pi/arduino/etc projects that anyone’s ever done 😃 but now you’ve done all that, no-one else has to go through it right? The beauty of open source! 😉 😂

Where do I send my £10? I have zero knowledge of and zero interest in farting around with fruit based computing.

All for saving £££’s but baulk at becoming a nerd to do so 🤣

I pooh poohed the idea of a smart thermostat butnow I think it would be handy to have for weather/humidity compensation.

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. You should be able to find what jet is in your boiler, and from that a flow rate per minute, hence how much oil has been used. It agreed with my measurement from the sight glass before and after adding a known amount of oil.

That sounds like exactly what ive considered doing – dont suppose youved open sourced it on Github or anything? <batts eyelids ingeek>

Hi Ewan,

Not on Github but happy to send you a copy, but I’m not a software engineer so don’t assume the software is any good! I’ve just looked at it and I have put a few comments in it, so should be fairly understandable, and it uses a standard library to drive the OLED.

Scratch. I believe there are variances in the insulating ability of “foam” tubing.
I used that silver face bubble wrap 50mm wide strip stuff – it claims to be as efficient at preventing heat loss as 35mm of rock wool.
In testing though (is it stupid to expect a non contact thermometer to be accurate? IR / laser beam type) the outer if a lagged pipe is only measuring at most 2 degrees lower temp than a bare pipe.
Maybe that type of temperature sensor is flawed on a silvered surface? Or on a copper pipe.

Almost half done now, but a bit disappointed on the result (measured non-contact). Room warmth will be a better test. I’ll report back. That unoccupied room with the pipes was getting pretty warm.

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You know that foil bubble wrap relys on an air gap to provide the quoted r value equivalency right ,?

You know that foil bubble wrap relys on an air gap to provide the quoted r value equivalency right ,?

That’s exactly what I was going to post. That wrap is way too tight.

It’s amazing how much difference the weather makes. It was 13C yesterday here and the heating was hardly on at all. Now it’s 9C and it came on in the morning and hasn’t been on since. At 13C the differential between the thermostat and outdoor temps is 4C, at -3C it’s 20C, so five times the heat loss resulting in 5x the heating requirement from the boiler even without the heat added from occupants and appliances.

I think adjusting this is where a smart thermostat (even without TRVs) would make a significant difference.

is it stupid to expect a non contact thermometer to be accurate? IR / laser beam type

My cheapo eBay IR thermometer is pretty inaccurate in certain instances. It seems to under-read at times, compared with the thermocouple one, but it doesn’t really work at all on pipes. Shiny surfaces seem to completely confuse it, but it’s also got a fairly wide spread so you cannot measure a pipe without getting the surroundings in as well. The spread is specified on the side of the device to give you an idea.

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 😉

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.

Stay Away from Foil-Faced Bubble Wrap

Terracotta indoor heaters

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….

Tea light heater by 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.