Another one from SciAm. Isn’t someone here a fan of painting roofs white?

https://pubs.acs.org/doi/abs/10.1021/acsami.1c02368

buffy said:

Another one from SciAm. Isn’t someone here a fan of painting roofs white?

https://pubs.acs.org/doi/abs/10.1021/acsami.1c02368

I mean this is fine but if you do the maths, the money would be better spent on other measures.

dv said:

buffy said:

Another one from SciAm. Isn’t someone here a fan of painting roofs white?

https://pubs.acs.org/doi/abs/10.1021/acsami.1c02368

I mean this is fine but if you do the maths, the money would be better spent on other measures.

Please show calcs.

The Rev Dodgson said:

dv said:

buffy said:

Another one from SciAm. Isn’t someone here a fan of painting roofs white?

https://pubs.acs.org/doi/abs/10.1021/acsami.1c02368

I mean this is fine but if you do the maths, the money would be better spent on other measures.

Please show calcs.

The Rev Dodgson said:

dv said:

buffy said:

Another one from SciAm. Isn’t someone here a fan of painting roofs white?

https://pubs.acs.org/doi/abs/10.1021/acsami.1c02368

I mean this is fine but if you do the maths, the money would be better spent on other measures.

Please show calcs.

1) Bump

2) When do you sleep? (and do you get enough of it?)

dv said:

buffy said:

Another one from SciAm. Isn’t someone here a fan of painting roofs white?

https://pubs.acs.org/doi/abs/10.1021/acsami.1c02368

I mean this is fine but if you do the maths, the money would be better spent on other measures.

“Ultrawhite BaSO4 Paints and Films for Remarkable Daytime Subambient Radiative Cooling”

Is Barium that much more expensive than Titanium. Titanium is the usual white of white paint. IIRC, barium sulphate is a byproduct of artesian bore water and of geothermal energy.

The following chart helps me to understand. BaSO4 has a low absorption of both UV and IR.

I should get my roof repainted i suppose now you’ve mentioned it.

You can feel the heat being reflected from a neighbouring white roof.

The neighbour is a chippie and reckons i should paint the roof myself ( maybe). Water blast it then treat with penetrol then paint. I’m fairly roof painters don’t bother with penetrol ( added cost and less profit)

I can do a test patch with the colorbond shade above one of the windows.

wookiemeister said:

I should get my roof repainted i suppose now you’ve mentioned it.

You can feel the heat being reflected from a neighbouring white roof.

The neighbour is a chippie and reckons i should paint the roof myself ( maybe). Water blast it then treat with penetrol then paint. I’m fairly roof painters don’t bother with penetrol ( added cost and less profit)

Do you want your house to be cool during the day or during the night:

• If cool during the day, then white paint.
• If cool during the night, then even black paint is better because white paint reflects the heat back down into the house.

There are probably special paints out there that have low emissivity (eg. white) in the visible range and high emissivity (eg. black) in the thermal infra-red. That’s what you really want. But I haven’t yet heard on any.

Come to think of it, gold was used as a covering for the Apollo LEM because it had that combination of properties. The best thermal solution would be to cover your roof with real gold. But that’s a bit expensive.

mollwollfumble said:

wookiemeister said:

I should get my roof repainted i suppose now you’ve mentioned it.

You can feel the heat being reflected from a neighbouring white roof.

The neighbour is a chippie and reckons i should paint the roof myself ( maybe). Water blast it then treat with penetrol then paint. I’m fairly roof painters don’t bother with penetrol ( added cost and less profit)

Do you want your house to be cool during the day or during the night:

• If cool during the day, then white paint.
• If cool during the night, then even black paint is better because white paint reflects the heat back down into the house.

There are probably special paints out there that have low emissivity (eg. white) in the visible range and high emissivity (eg. black) in the thermal infra-red. That’s what you really want. But I haven’t yet heard on any.

Come to think of it, gold was used as a covering for the Apollo LEM because it had that combination of properties. The best thermal solution would be to cover your roof with real gold. But that’s a bit expensive.

I do have some rolls of gold leaf but I’ll need to order some more.
Might be cheaper to go live in a Buddhist temple.

wookiemeister said:

I can do a test patch with the colorbond shade above one of the windows.

Do get back to us with your results.

roughbarked said:

wookiemeister said:

I can do a test patch with the colorbond shade above one of the windows.

Do get back to us with your results.

There are special thermal insulating roof paints. e.g. https://www.solacoat.com.au/

Tamb said:

roughbarked said:

wookiemeister said:

I can do a test patch with the colorbond shade above one of the windows.

Do get back to us with your results.

There are special thermal insulating roof paints. e.g. https://www.solacoat.com.au/

Ta. I might investigate that.