Wall insulating paint

Ben84

Paint is extremely thin, about the thickness of ordinary typing paper. I don't believe there is any known material in the world that would give you a decent amount of insulation in this thickness. As for reflecting heat, the particles are embedded in the paint, not on the surface. For reflecting, *only* the surface or a material matters. A mirror for example is no longer effective for tidying your hair when it's embedded in paint.

rogerblack

Ben84 wrote: »

As for reflecting heat, the particles are embedded in the paint, not on the surface. For reflecting, *only* the surface or a material matters. A mirror for example is no longer effective for tidying your hair when it's embedded in paint.

There are low emissivity paints.
I'm unsure that any of them are domestically available and suitable.
http://www.solec.org/LOMITMenu.htm - for example - claims a 0.15.
http://www.rimainternational.org/technical/ircc.html verifies this, though I'm unsure how independant this source is.

http://www.cenospheres.net/pdf/CamoPaint.pdf outlines in lots of detail some of the issues, and presents a 0.5 emission camo green paint, or ~0.3 for silver.

Some binders have low absorbtion in IR.
I question if the 0.15 figure is real - note that that paint gives a spectrum only out to 2.5um, which humans that are not on fire do not radiate.
However - clearly better than 0.9ish is possible.
If it's actually available in a form suitable as domestic paint is another question.
Sure - it's possible to do it today, just by mounting foil-backed plasterboard backwards, but...

zeupater

rogerblack wrote: »

And they'd be basically wrong.
What you care about is the paint 'colour' in the infrared - far beyond the visible.

In this wavelength, for example, "energy saving" windows are mirrors.

http://www.x20.org/library/thermal/emissivity.htm is the first table I found.
You can see that most paints are around 0.9 or so.

A paint with a low emissivity - and hence a high IR reflectivity may make a space feel warmer, though primarily if you're close to a wall.

I can't see a situation where it's going to make the room feel much warmer though in general, unless you have some form of radiant heat covering an entire wall, floor or ceiling.
In that case, then yes it will.
Otherwise, the things the walls are reflecting will be the cold contents of the room, and it's not going to help.

Incorrect .... they would basically be right.

If you check my post you will see that in the last couple of posts you have confirmed my figures ~0.9 for black paint to ~0.3 for silver paint and if you check you will find that the shiny side of aluminium foil is 0.05, that's why both the condenser on the back of your fridge and higher performance designer radiators are dark colours and shiny reflective aluminium facing is used in insulation products such as Kingspan.

I agree that until the surface has a highly polished light coloured surface the emissivity between paint colours is very small, but it is there and that's exactly what any manufacturer of a low emissivity paint would play on .... the difference.

Absorption has is much greater range between colours. Due to the energy absorption/reflection ratio a dark coloured surface will warm more than a light one, that's why solar thermal collectors are painted dark colours and why my white painted external walls stay cool and the brick ones warm up when in sunlight.

If I was overconcerned by the heatloss in my house I'd not paint the internal wall opposite my log burner black, but a light colour in order to reduce the amount of energy absorbed as it is this form of heat transfer which is important, if I was really obsessed I'd certainly stick aluminium foil on the surface ... the reference to emissivity was in response to an obviously infactual post claiming that the 'special' paint's properties were due to emissivity & absorption by a poster named 'Emissivity' so emissivity looked like a good theme to pick up on, even though absorption of heat by the thermal mass of the building is what cools the air and makes you feel, and be, colder ....

I would still challenge anyone promoting these thermal paints to provide data on the thermal properties of the paint (u-value/r-value) or the emissivity value of the paints v standard paint of the same colour on the basis that they seem to concentrate on emissivity not absorption, but they might as well provide absorption comparisons too :D

HTH
Z

A_Tight_Engineer

I was looking at the Thermilate website and their claims are very impressive but not backed up with any figures or test data. The plaster products have some conductivity numbers, poorly presented which show that a 50mm layer halves the heat loss of an uninsulated 2W/m2/K wall (ie a very poor one).
This is feasible, I have just had an old house plastered with a lime plaster mixed with hemp fibres. Figures for this are very similar to what is claimed by Thermilate.
For the paints however they make big claims but are very vague about numbers. It is impossible to quote a 25% energy saving without an idea of the efficiency of the original structure. also due to the thickness of a coat of paint - a few microns, it is impossible to have a significant reduction in conducted heat - this is the largest contributor to heat loss through a wall, so the emissivity arguments are largely irrelevant. Reducing conductivity at the surface can make a surface feel warmer to the touch, especially if it has a very low heat capacity, but will not have an effect on heat loss.
(Noting I am a dubious newbie) it seems fair to conclude that while the plaster is probably a useful product the paint or additive cannot make any significant difference, hence the lack of hard figures on the site.

Mistral001

I agree with the above poster. The claims by the manufacturer have to be read carefully and a little common sense used. The coating is very thin and thus has those limitations.

Also the OP has mentioned that he/she is planning to use it in their landing and hall onyl of a detatched house, thus the external walls would only make up a very small area of the overall wall surfaces of those areas of the house. Thus the 2% advantage would further be reduced. If a serious attempt to reduce heat lost was to be made then dry-lining has to be considered.

Cardew

Mistral001 wrote: »

I agree with the above poster. The claims by the manufacturer have to be read carefully and a little common sense used. The coating is very thin and thus has those limitations.

Also the OP has mentioned that he/she is planning to use it in their landing and hall onyl of a detatched house, thus the external walls would only make up a very small area of the overall wall surfaces of those areas of the house. Thus the 2% advantage would further be reduced. If a serious attempt to reduce heat lost was to be made then dry-lining has to be considered.

As the OP posted nearly 4 years ago he may have already discovered their (in)effectiveness if he used the product.;)

Since the content of internet websites came under the auspices of the Advertising Standards Authority(ASA), companies are getting more artful in wording their claims.

The still seek to deceive by implication, but preface claims with clauses like 'up to x%'. - 'up to 20%' covers from zero

whasup

Solar reflective paints have been around for years. They are commonly applied to flat roofs to help keep the roof cool. Vaguely interesting fact is that they always used more or less exclusively silver but the more recent ones tend to be off-white or grey which is slightly counter intuitive.

The thermilite site makes me larf. The site asks; 'How does Thermalmix Work?' And then gives the answer; 'Paint mixed with Thermalmix creates a unique thermal barrier'. Oh is that how it works? Creates a unique barrier does it. What a load of rubbish. Testing the emmissivity of a paint before and after the additive would be a pretty simple thing to do and would provide some rational evidence as to its effectiveness. So why don't they do it and show us the results. Doesn't take a genious to work out the answer to that.

Johnandabby

Seems to be more and more companies selling these now, as people are looking to save money on their heating bills. Latest I've seen is an American company called Temp-Coat, with it being (and I quote) an 'industrial designed liquid acrylic latex ceramic insulation'..... Throughout the Application Guide it continuously states that it's not a paint...

I've been asked to look into it for a client, so have asked for information on thermal properties, UK third party testing etc... I'll let you know what I find

rooferuk

Thermilate Technologies products are rubbish , the roof coating that I have been buying from them flaked off the roofs within 4 months , the guarantee isnt worth the paper its written on .
I now buy my own paint from the my local merchant , and mix in the Thermal Insulating Roof Additive , which I buy off the Internet alot cheaper than these idi0ts sell for , PLUS it is the genuine product.
DONT BUY ANYTHING FROM THEM AND THEIR WEBSITES .
ITS ALL CHEAP RUBBISH......

DaveAt168

Let us start by being fair. Applying a 2mm coat of this paint to a 100mm wall covering of expanded polystyrene will make absolutely no difference.
Applying it though to 9" of solid brickwork, or worse, 4.5", will make a HUGE difference.
We have the same problem with the supergreens.
Starting with bare bricks, the first 2mm of insulation makes an enormous difference.
Think of it as an electrical circuit, the temperature difference being the voltage, the heat leakage, the current, and the insulation, the resistance.
For argument, shall we say that the resistance of brick is 1 ohm/mm, while that of polytyrene foam is 1000 ohm/mm.
The solid brickwork, at 9", or 220 mm is then 220 ohms, while the resistance of the polystyrene foam, at 2 mm is 2000 ohms.
The insulated wall section now has a resistance of 2220 ohms, which, you can see is equivalent to increasing the wall thickness to 90",
That is, the insulation is increased by a factor of 10, so the heat loss is reduced by 90%.
Doubling the insulation to 4 mm will then reduce the loss from 10% to 5%, and so 40mm will reduce it to 1%.
So, you can see, the first 2mm of insulation achieves five times more than sticking 4" of insulation on the walls.
If you are in the situation, then of having solid brick or stone walls, and you do not want to lose valuable room space by dry-lining, then, if you can apply a coating, shall we say with a resistance of say 10 ohms/mm, then a 2mm coating of this paint will raise the resistance from the basic 220 ohms to 260 ohms. Not an incredible increase, but for the same voltage, the drain will be reduced by about 15%, or turning that on its head, for the same heat loss, the temperature drop through the wall will be increased by 18%.
Shall we say the outside temperature is freezing, or 0 ̊C, and the heat setting, before the insulation was applied, resulted in a room temperature of 20 ̊C, then the inside surface of that wall will increase by about 4 ̊C.
These figures seem to match the values claimed by most of these additive manufacturers.
Their claims, with in their context seems to be entirely plausible.

The more paint you can slap on, the better.
And yes, a top coat of untreated paint is a good idea.

As a cheaper alternative to the customary dry-lining, (do you remember those dreadful polystyrene ceiling tiles, so lethally applied to kitchen ceilings?) We covered the exterior wall, from the skirting to the ceiling with these tiles, including the window reveals, then, when the tile were secure, we slapped old emulsion paint on the new inner surface, then dabbed, and dotted 8 mm plasterboard straight on top of these tiles, the boards horizontal, standing on the old skirting boards. By good chance, these boards were flush with the old skirting boards, and we simply nailed new skirting boards on top of the old ones. Voila! Job done. Simple, took less than a weekend.
If you take drying time out, less than half a day. If you go back to paragraph 1, and consider that these ceiling tiles were 6 mm thick, this reduced the heat loss by over 90%. The devil can argue over how to subdivide that remaining 10%. The house need ventilation anyhow, and even heat recovery ventilators are only about 60% efficient. That 10% is down in the noise. You can fight over it, it is the 90% which concerns me.