SteamyTea

Putt my chef's hat on for a moment, if people can't cook, then the choice of hob is irrelevant. Those that can cook, prefer an induction hob. And don't fall for the nonsense about 'you need thick based pans on an induction hob to spread the heat', that is only said by people that can't cook.

And the other comes from plants, possibly. We used to use a vegetable oil derived polyol, worked just the same as the others. If it can be made from oil, it can be made from plants, usually.

As with all things, none of them are bad, if done right. Personally, from my limited experience, the sound deadening qualities of cellulose would make it my choice. I think there are two ways that this gets installed, dry and wet. I think from memory that the wet method reduces the chance of slumping. There is also the bigger environmental picture. Cellulose is a recycled product, which may, or may not, be environmentally better (mineral wools have a very low embodied energy though). As for the 'off gassing' of polyurethane and phenolic based products, not a problem these days, 50 years ago maybe it was, but we survived the 1960s and 70s. If you are really irrationally worried about it, get rid of your sofa, mattress, car steering wheel, carpet underlay, then move up an isolated mountain, make sure that all combustion technology is banned within 500 km...

What unit rate is the electricity at? Insulation, for any given k value, is by the nature of arithmetic, a diminishing returns calculation. Why not just add some extra insulation to the north facing walls. They will always have a lower mean temperature, so will benefit the most.

Very true. Stopping it getting properly wet in the first place should be the main objective. Cement based can be just as porous as any other bases. Really down to the mix being suitable for the job. Trouble is, there are too many ill informed tossers working in the building trade. Check the ground level outside first, it pay be easier to remove a spades width of build up soil.

That is probably the most important bit and the part of the solution that is probably not done properly, if at all. Too many people want to treat damp as a decoration problem, not a physics problem.

Indirectly I have been affected. People are eating out less, as they have less cash to spend on such luxuries. We have had two price shocks in the last 20 years. Neither of them have been bad enough to make a material change to our heating systems, so maybe just price isn't enough. Changing the taxation on fuel to a carbon base would help. It really is totally wrong that most pf the carbon tax is on electricity production, but domestic gas burning, which is very inefficient, hardly has any 'because it is better than coal', a fuel that is hardly used for home heating at all these days. Apart from your great age, why. Seems to be very much the same, with everything going on behind the scenes, just the way it should. Get up to a warm house, have a shower or bath, go to work in a car, have lunch (I often have a non meat lunch when working), go for a walk in the woods/hills/beach, go home and watch streamed TV, sleep. Really no different from today, or 50 years ago.

What is the fraction of wall area to over all area. Would it cost more or less to improve windows and doors, extra ground insulation. Adding PV could be a cheap option to reduce ongoing cash expenditure. Get the airtightness better, which isn't cheap to do, but saves loads.

Welcome Was it a kitchen. or an unheated room? It may be worth leaving it a while to see if it dries out naturally. Did it really work. The physics says it should, but I have always been dubious. Too many other variables for my liking.

That is a shame, but not surprising as it was probably organised by the sales team, or worse, the PR department.

Liquid water takes 4.18 kJ/kg.K. When it gets to a vaporisation temperature, which is dependant on air pressure and ambient humidity, it take 2257 kJ/kg to change state. Now myself and @Gone West looked into this a while back, and I think a common brick can hold around 8% of it's mass as liquid water. Say a brick has a density of 2000 kg/m³, there could be an additional 160kg of liquid water to heat, and then convert to vapour. Brick takes about 0.8 kJ/kg.K. An ordinary brick has a mass of about 2.8kg, add on 8% water and that is another 0.2 kg. To initially heat by 1 K will take. 0.8 [kJ/kg.Kbrick] x 2.8 [kg] x T [Tfinal - Toriginal] + 4.18 [kJ/kg.Kwater] x 0.2 [kg] x T [Tfinal - Toriginal]. 2.24 [kJ/Kbrick] + 0.836 [kJ/Kwater] = 3.01 kJ/g. At vaporisation point. 0.8 [kJ/kg.Kbrick] x 2.8 [kg] x T [Tfinal - Toriginal] + 2257 [kJ/kg.Kwater] x 0.2 [kg] x T [Tfinal - Toriginal]. 2.24 [kJ/KBrick] + 451 [kJ/Kwater] = 453 kJ/g. A huge difference. Though it does not happen all at once.

No. They may, possibly, help reduce convection currents, but overall, perform no better than a bit of clingfilm.

Basically what I intend to do. I remembered I have some of that, I know it is great for covering a tent when it is sunny. I also intend to fill one up with different solid materials and see what happens. Almost like being back at University, I never understood people that wanted to do anything outside of the laboratory. I should have studied Mathematics, then the lab is just paper, pencil, eraser and maybe a laptop to type it up on. Wonder if I could get a job doing that with my statistical analysis skills, the only skills in statistics is counting and explaining after all.

It can be distributed though. More plumbing, though if you have two bathrooms, a downstairs bog and a kitchen, not much more. You are, after all, just running a cold feed to each heater. There is a case for properly sized instantaneous heater, though they may need a huge power delivery and cannot make use of ToU tariffs. Then there is the 'ecocent' type HPs with storage. Especially useful if you need to ventilate your old, damp, thermally leaky house.

The heat capacity may change, but I am not sure that makes much difference. High heat capacity fluids are used because they require less power to move them about, but as the pumping power is so low anyway, I don't think you would measure the difference in a heating system.

Reading off the above chart. At a temperature difference of 25°C, the foil will perform better. Though I am not sure what the question really is.

When I was getting a new unit for my back door, I wanted 16mm gap as I read, somewhere, that was the optimal gap. I was convinced that 20mm was better because of the sound transmission. This experiment was really about the difference between reflective and transparent barriers though. Not really, because the differences are too small to be meaningful.

Wish it was for me. It is, as you acknowledge, small because of our leaky houses. Environmentally heating water with a resistance heater is not going to be a problem, the problem is generating enough low carbon electricity. If we say a house uses, on average 4 kWh/day for DHW, that is 120 GWh a day for the nation. A basic HP with a CoP of 2 will halve that.

Well I suspect that the tests I am now running will show that stopping air movement with a lightweight filler improves things.

It has been a cold week, so just after 12:30 on the 15th of January 2024, I started a small, but limited, experiment. This was rather prompted by a comment by @Garald who wanted to insulate at the back of his book shelves, and mentioned our favourite insulation, multifoil. @Gus Potter also has a project that may benefit a thin, easy and cheap to make, insulating panel. I think I also made a comment to @saveasteading about this experiment, but can't remember in what context. Now I have always been dubious of reflective type insulation. Works great at high temperature, especially in a vacuum, it is how the cameras on the James Webb Telescope are kept cool. But we are not Billionaires, so I used hardboard, pine, white emulsion paint, double sided tape, small screws, clingfilm and aluminium foil. Basically I made some small St. Ives picture frames, put them face to face, separating the 24mm air gap with clingfilm in one, and aluminium foil in the other. The total thickness of the test panels is 30mm. Each side of the test material had temperature sensors (DS18B20s) inserted via holes in the frame. These had been calibrated before hand and the analysis is based on the calibrated data. Other sensors where fitted in the room and externally to log ambient temperatures (why being a cold week was so good). The panels were then stuck to my kitchen window with double sided tape. The position of the sensors allows for a combination of temperature differences to be logged, logging was at the minute interval but the analysis was based on 6 minute means. A quick calculation to check the standard error showed that accuracy was a factor of at least 10 below the 0.1°C accuracy of the experiment. The data analysis was based around temperature differences, but for some context, internal and external air temperature is also shown on the charts (right y-axis). A frequency distribution line was also added, this is black line (right y-axis) and is called Ambient ∆T Probability Percentage. The Ambient ∆T is the difference between the inside temperature and outside temperature. This is also used for the 0.1°C temperature bins that create the x-axis. Mean temperature differences between each side of the clingfilm or foil (shiny side towards warmer room) were also calculated and binned according to when they happened with respect to the Ambient ∆T. This method is used as it is more relevant than a time series that can fluctuate during the day, it is the properties of the insulation that is being tested, not the absolute 'comfort' levels. The below chart shows the total test period results. Test period (15/01/2024 12:26 to 19/01/2024 12:42) Always remember that these are temperature differences and not absolute temperatures, except the Internal and External mean temperatures (yellow and green lines) and the probabilities (black line). Those 3 are read from the right hand axis. The Clingfilm is the red dots and the Aluminium Foil is the blue dots. Linear trend lines have been added more for clarity than actual predictions. A can be clearly seen, there is not much difference between the two datasets. The Clingfilm performs better overall with a mean difference of 2.5°C, to the Aluminium Foil's 2.3°C. Above an Ambient ∆T of 19°C the Aluminium foil performed a little better. This is actually saying, the colder it is outside, the Aluminium Foil performed better, which may be important comfort, but overall, there will be greater energy losses than with just using Clingfilm as a separator. It is, purely from a climate change viewpoint, the overall energy reduction that is important. Climate change has caused the mean temperature at my end of Cornwall to average -0.1°C for 4 days. I have lived back here for 20 years and never known such a prolonged cold period. I am now running a second test, using one panel without any separator at all, and the other one fully filled with silica micro balloons. Micro balloons may sound exotic, but they are just filler used in the plastics industry. I don't think the temperature differences are going to be so great next week, which is a shame as the greater the range that can be tested, the better. I can always raise the temperature in the room to compensate, but as I raised it up to 24.5°C a few times, which resulted in only getting a mean of 23.5°C in the room, it will be a bit costly and not very environmental. I shall post up the results of the second test next week, all going well.

Yes. And not a small amount either. Price shock the market to force change.

Maybe, maybe not.

Hardly recent, this has been known about all my life.

Don't fall into the trap of just making the inside airtight. You need to stop air bypassing the insulation. Then worry about ventilation, MVHR is best and easy to fit when the place is empty.

That could account for it then. I have booted up one of my old Pis and shall see if I can get the proper libraries on it. Thanks again, most days are school days. (just spent over a day looking for my old car V5 document, found some "O" level certificates, they are well over 40 years old, and my Birth Certificate, which is even older. I did find the V5, right where I left it.)