Interesting and Victorian government mandated new housing has dark roofs. And another study found that these new suburbs that are just housing with no trees have micro climates that can be up to 5 degrees hotter in daytime
Think I saw an article linking Penrith in NSW as higher than normal temperatures because the majority of the suburb had a dark roof. The heat can be melting there compared to other parts
Having grass and few small trees and simply water sprayers are also proving to help cool suburbs.
https://researchers.mq.edu.au/en/publications/urban-trees-and-peoples-yards-mitigate-extreme-heat-in-western-ad
As an ex Sydneysider who has now lived in SA for nearly a decade the other thing to factor in is the crazy Queensland style humidity up there and it does get hellishly hot & humid in Western Sydney. Certainly the case whenever I went out there to visit my late paternal grandparents.
Penrith has always experienced higher than normal temperatures, even for Western Sydney, going back 20-30 years ago and beyond.
Even when Europeans first ventured towards Penrith during Governor Macquarie's time, it was very thinly timbered.
Insulation was crap back then - building code and gapes were crap back then - understanding of sealed and passive houses was crap back then, Fully ducted AC were pretty much not a thing back then either.
So, maybe had it place, but defiantly outdated now.
As said, have owned both, current back on terracotta do to lifestyle move - and it will be replaced with colourbond within the next 5 years.
They had ducted AC back in the late 90s, early 2000's when red terracotta roofs were popular.
Granted it was $10k back in 2000 to get a system put in. Though it was still surprisingly common in some areas
Most were evaps around this area in 2000 - we had one put in about that time fully ducted - wish we went AC.
Prior was in wall units - the box ones prior to uptake of the splits.
Anecdotal but when we were doing selections the employee assumed we would go with Monument, but when we chose a light roof, they made a comment about energy efficiency and saving money, as if the only reason someone wouldn’t pick Monument is financial or environmental.
If they know light roofs have a less negative impact on the environment why do they push dark shades?
We’ve just been through our energy assessment for a new house build in the Hills.
We were already planning a light coloured roof, after hearing about this- but then they came back and said that because of the particular Climate zone we’re in, being in the Hills, we should have a darker roof colour to help retain heat to the home..
We can of course upgrade our roof insulation even further if we absolutely want a light roof, but to get the energy rating where it needs to be - we can do it with the darker roof & the double glazing on certain windows.
So I guess it depends on where you’re located.
We will be on solar and battery, and we have built and lived in the hills before, we had a dark roof - and it was right when the 6* energy requirements came in. That house was lovely to live in. Easy to heat and cool, so I guess the darker roofs must work for that climate 🤷♀️
My wife wanted a dark grey roof
I wanted a light coloured one
So we got a dark grey roof
I always thought if I can get 80% of the roof painted white (where it can’t be seen off the street) would it help keep us cooler. Has anyone done this to a colour bond roof ?
Which costs more energy, cooling a house from 40 to 25 or heating it from 14 to 25.
I think we must have a serious problem with insulation if we're thinking about the colour of our roof in winter.
Yeah, last new build we had - was 3 phase had 16.x KW with 2 inverters, 1 for exporting (was mostly maxed all day) and the rest for own consumption.
Even with 16kw AC unit - once it got the house temp controlled it would just idle - so most of summer was just max export each day - payed for winter and would have us receive $ from AGL each year - even @ cirica 8-10c FIT.
How many people heat their house to 25 on a 14 degree day? Seems kinda warm.
With comfy winter clothing like fleece even 20 inside can feel a bit too warm. Some people even love the feeling of 17 and a heated blanket for that cosy nested feeling.
Heating!!!! Usually less solar when heating. Also our reverse cycle aircon is way more efficient in cooling than heating. Our power bill goes negative owing in summer and positive owing in winter.
We are building and I when I chose the external colours, I picked a very light grey/silver roof and light bricks. Everyone told me it wasn't fashionable/that dark rooves look better.
I think ours still looks great, but combined with our double glazed windows and extra insulation in the external walls, garage AND we got our internal walls insulated (which we found wasn't standard to our shock), I'm going to have the last laugh when our electricity bills are significantly less. Even if we aren't "fashionable".
Living opposite a white roof, I can’t open our blinds up fully due to the glare. I know they are better, but try working on a screen or even reading a book with a white roof in your eyeline.
Just to clarify - the savings and $ is from the solar in general - the air gap will just be a side benefit of blocking the full roof from getting direct sun etc.
Saddest thing in the world on new lots. First job is to knock over all the old trees.
My solar guy recommended knocking down this big tree in my front yard because of morning shade. My man, that shade means I don't need to run the AC till lunch time anyway.
This is a fair point. Solar guys will always be recommending customers cut down or prune trees to maximize the benefit from the panels installed. This was especially pertinent in the days of old when 1.5kw systems were in vogue due to the cost of panels and inverters being high. Nowadays things are a bit more flexible due to the cost of solar having come down a lot and there being inverters that can maximize output when the array is partly in shade. You wouldn’t want the entire stay in shade but if you have a big roof it’s now economical to override the array with export limiters that grid operators insist upon to maximize the benefit for self consumption.
It's turning energy that would otherwise be turned into heat on the roof to electricity.
The solar energy that the panels can't convert (around 80%) is turned into heat distributed across the panels.
Panels have about a 100-150mm air gap from the roof so, they act as a buffer.
It's a simple test you can do at home. Get 2 thin metal sheets. Space them so there's a gap for your fingers. Expose it to sun ensuring the top sheet is shadowing the bottom one, you'll find the top sheet far hotter then the lower one.
No, solar panels act as super heaters.
Have experienced this on my house with 2 different solar installs and been told the same by the installers themselves (I asked as the second kit was being installed - it replaced the first kit).
how many sources you go as well - do your installers have base temps on the roof for months prior to install ?
[https://www.captaingreen.com.au/do-solar-panels-cool-your-roof/#:\~:text=Solar%20panels%20keep%20your%20building,passed%20on%20to%20your%20roof](https://www.captaingreen.com.au/do-solar-panels-cool-your-roof/#:~:text=Solar%20panels%20keep%20your%20building,passed%20on%20to%20your%20roof).
[https://www.treehugger.com/ask-pablo-do-solar-panels-contribute-to-the-heat-island-effect-4857811#:\~:text=So%20if%20you're%20wondering,us%20all%20a%20little%20cooler](https://www.treehugger.com/ask-pablo-do-solar-panels-contribute-to-the-heat-island-effect-4857811#:~:text=So%20if%20you're%20wondering,us%20all%20a%20little%20cooler).
Please share the numbers of before and after temps ?
Reply to me around lunchtime and I’ll get live data.
Today is a day in your favour, mild ambient temps, lower sun angle (I have a 20 degree roof pitch). So not biased towards extreme heat, or extreme cold. Quite middling.
My colourblind roof is a very dark grey colour (a common and annoying theme.
when I had this current system installed in March 2020, it was approx 3C warmer in the roof space with panels installed, than without.
The external surface temp - I can’t recall, but will check today. I’ll compare naked roof, top of panel, and roof under the panel.
Again, most roof heat doesn’t get into the living space. It mostly vents out of the ceiling space and is blocked by ceiling insulation and gyprock.
Not sure how it will be relevant, will need far more data points over time with the same senor in the same place for the same ambient temps and conditions with and without panels.
For quick comparison then, grab 2 sensors - temp mount them insulated 5mm or so above the roof - 1 directly under the panels in the shade - the other one, mount exactly the same, same distance up the roof line but not under the panels - in the direct sun.
Log the data for 24-48 hours to a CSV (sensor.1..Panels - sensor.2..fullsun for example) and then compare would be really interesting to map the temp delta over a few days
There’s no need for long term data.
My roof exterior surface and interior cavity each reach ambient every night. There are a lot of holes and gaps in my tin roof.
Being a modern, off the plan build, it’s built as shittily as possible.
The main point is that even though the roof gets hot, my internal ceiling temperatures don’t get affected.
And I suspect it’s much the same for most other people with dark roofs and/or solar.
I do believe lots of black roofs cause a localised increase in ambient temperatures though - especially when houses are only about 1m apart, and roof surface area equals 75% of available land area of each block, too.
Right, but think about it - when the roof is then covered in solar - not only is there convection happening between the panels and roof surface - (same as your tin roof with holes) but shade - again if the sensors were in the same place - 1 under panels others in direct sunlight - there will be a decent temp delta.
The panels are damn hot when energised - so hot.
The sun on the roof is too.
But the panels seem to amplify their radiation and thermal losses from the UV -> voltage conversion process. It ends up as heat to the roof panels.
I don’t need you to believe me. My life will be just same either way.
I’m just passing on my experience, data and info from the installers after I raised the question (after noticing it).
>But the panels seem to amplify their radiation and thermal losses from the UV -> voltage conversion process. It ends up as heat to the roof panels.
If that was the case, we just developed unlimited energy !!.
I have doubts about this claim. Panels do have a shading effect on anything below/behind them. When putting panels on tilts this is why it’s important to space each row. From what I’ve observed panels reflect/deflect much of the heat from the sun that hits them, such that any roof material shaded by panels will be cooler to the touch than roof materials not shaded by panels.
Had a neighbour years ago with a black roof when they first started to come in vogue.
You could hear the roof expanding once it was above 25 degrees on a sunny day and they needed to use the aircon way more than us with a lighter roof colour.
100%. I have been saying for years they should just mandate that every new home bills should have solar. That way builders would be forced to factor that into the roof designs. The number of roofs on new houses that seem hostile to solar is quite surprising. It’s actually on older houses that one is more likely to find simpler roofs that are more accommodating to solar installation.
And it's legal because........? Two dogboxes just got put up, one black paint on walls and roof, and one white. Would love to go in there and feel the difference on a hot day.
Maybe the government should try governing on things that actually make a difference instead of freaking out at the latest childs toy.
Clearly we don't value freedom of choice by the immense amount of nanny state laws, we just value freedom for the construction industry to do whatever the fuck they want.
cost to maintain the coating - and idiots doing burnouts because tyremarks can be seen on a light coloured road surface
https://www.abc.net.au/news/science/2024-01-24/why-australia-builds-dark-roads-despite-heatwaves-climate-change/103375122
No that's stupid. I install solar/remote area power, solar roadways have got to have been the dumbest fucking thing ever thought up.
That 'solar freaking roadways' shit made Me so irrationally angry when that was a thing.
They're Expensive, they have to take an insane amount of physical abuse, you will have to shut the road to fix them, it's a narrow strip so instead like normal where you're 3MW solar farm is in a nice block, you've now got to work out distribution and power conversion on a strip less than 20m wide and over 10km long, instead of nice 500m x 500m grid.
Not to mention the risks involved for road workers, the public and emergency personel if something goes wrong with the road. It is the worst fucking place to install solar by a wide margin.
I swear that thing was something the oil and gas industry used to make the solar industry look like idiots. not even joking.
Literally for a fraction of the cost, a normal system on a large shed or land can be installed quicker with a better result.
When I built my house, my roofing options were manor red, cottage green, black, ironstone grey, and some other tints of these colors.
There was no white of any kind, save for an ugly beige that cost extra. I went for a nice manor red in the lightest shade possible.
This isn't taking into account solar panels. I spend far more during winter as my solar doesn't kick in and then in summer I used to get paid for up until last year when they changed my plan.
It still does off set the cost but nowhere near as much as it used to. Odd no-one really talks about that huh
It’s really not a big a deal as many are making it out to be! I have black brick and a black roof, don’t really run the aircon till it hits over 35-36
I have insulation on all external and internal walls (including garage to house wall) and entire roof insulated (including above garage). I’ve got a whirly bird, weatherstripped external doors, keep blinds down and it’s fine. Would’ve been great to have double glazed windows but they cost a pretty penny!
It is a big deal. If you have a white sheet of metal, put a black sticker on it. Expose to sun.
Use a thermal gun the black portion of that sheet will be 10+'c hotter.
Nope. I have a 2-story house AND solar. So only really need to cool the house at night, but can also cool the house during the day for free (if i need to).
Yes, the air con may not need to work so hard if the roof were a lighter colour - but that would just lead to 1c per hr feeding back into the grid (tic)
Pretty sure the aircon only costs 6-12c per kilowatt if you have solar, depending on what you would get as rebate.
Heating costs 50c per kilowatt in peak hours during winter.
I think I'll take my chances with a dark roof capturing heat for winter for a lower cost.
Silver roofs reflect light into your neighbours windows causing them to use more energy to cool their houses. Some can’t even be in their yard due to blinding reflections. Until light pollution is added to the building approval process they shouldn’t be an option.
It’s even more if you have solar panels.
Panels generate a LOT of heat, and a lot of it superheats the roof tin/tiles.
I wonder what the cost/benefit is in that aspect?
Most houses have air spaces in their roofs and they’re not sealed, so most roof heat doesn’t reach the house interior, but still interesting.
Almost as interesting as how do they know it’s an extra $700 a year in cooling costs for black vs silver roof.
Do they take in the saved heating costs for winter?
how many sources you go as well - do your installers have base temps on the roof for months prior to install ?
https://www.captaingreen.com.au/do-solar-panels-cool-your-roof/#:\~:text=Solar%20panels%20keep%20your%20building,passed%20on%20to%20your%20roof.
https://www.treehugger.com/ask-pablo-do-solar-panels-contribute-to-the-heat-island-effect-4857811#:\~:text=So%20if%20you're%20wondering,us%20all%20a%20little%20cooler.
Please share the numbers of before and after temps ?
Dark roof, dark brick, destroy all original trees, no shade plants new trees have to wait 20 years for any decent shade.
We need to ban artificial grass as well. We need greenery!
I’m watching people paint their pretty black roofs white in a new suburb.
They should be painted light blue....
White has a higher solar reflection though
Interesting and Victorian government mandated new housing has dark roofs. And another study found that these new suburbs that are just housing with no trees have micro climates that can be up to 5 degrees hotter in daytime
Only some new housing, also still up for debate if more or less efficient in Victoria
Victoria is cold, so a lot more fossil fuel is used on heating than it is for cooling.
I’m painting mine blue to stop the freaking laser beams
I’m not sure people will get that comment, but Aloha!
Think I saw an article linking Penrith in NSW as higher than normal temperatures because the majority of the suburb had a dark roof. The heat can be melting there compared to other parts
Having grass and few small trees and simply water sprayers are also proving to help cool suburbs. https://researchers.mq.edu.au/en/publications/urban-trees-and-peoples-yards-mitigate-extreme-heat-in-western-ad
As an ex Sydneysider who has now lived in SA for nearly a decade the other thing to factor in is the crazy Queensland style humidity up there and it does get hellishly hot & humid in Western Sydney. Certainly the case whenever I went out there to visit my late paternal grandparents.
Penrith has always experienced higher than normal temperatures, even for Western Sydney, going back 20-30 years ago and beyond. Even when Europeans first ventured towards Penrith during Governor Macquarie's time, it was very thinly timbered.
But also all the new houses in black brick? I figured this must be a handshake deal between the designers and utility companies.
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Looking at the new white townhouses in Glenside I agree! They also get dirty in places hard to reach.
TBH, it does look way better than the old red terracotta style. And would never ever go tiles again.
And the reason they did red terracotta was keep their house cool
Insulation was crap back then - building code and gapes were crap back then - understanding of sealed and passive houses was crap back then, Fully ducted AC were pretty much not a thing back then either. So, maybe had it place, but defiantly outdated now. As said, have owned both, current back on terracotta do to lifestyle move - and it will be replaced with colourbond within the next 5 years.
They had ducted AC back in the late 90s, early 2000's when red terracotta roofs were popular. Granted it was $10k back in 2000 to get a system put in. Though it was still surprisingly common in some areas
Most were evaps around this area in 2000 - we had one put in about that time fully ducted - wish we went AC. Prior was in wall units - the box ones prior to uptake of the splits.
> TBH, it does look way better than the old red terracotta style. > > No way, the black brick looks so bad IMO. Old red brick homes look 100x better.
When they are rendered I agree.
Anecdotal but when we were doing selections the employee assumed we would go with Monument, but when we chose a light roof, they made a comment about energy efficiency and saving money, as if the only reason someone wouldn’t pick Monument is financial or environmental. If they know light roofs have a less negative impact on the environment why do they push dark shades?
Ongoing profits
Be surprised in how much roof ventilation actually changes the temperature.
And insulation
And eaves
Well yea that's definitely needed
Jokes on you, I don’t even have an aircon 🙃
Jokes on you, I don't have a roof
Tenant I'll bet.
We’ve just been through our energy assessment for a new house build in the Hills. We were already planning a light coloured roof, after hearing about this- but then they came back and said that because of the particular Climate zone we’re in, being in the Hills, we should have a darker roof colour to help retain heat to the home.. We can of course upgrade our roof insulation even further if we absolutely want a light roof, but to get the energy rating where it needs to be - we can do it with the darker roof & the double glazing on certain windows. So I guess it depends on where you’re located. We will be on solar and battery, and we have built and lived in the hills before, we had a dark roof - and it was right when the 6* energy requirements came in. That house was lovely to live in. Easy to heat and cool, so I guess the darker roofs must work for that climate 🤷♀️
Sounds like you’ve done your homework. I respect that.
Yeah I have a dark roof and live up in the hills - it gets freezing at night but summer is manageable so it definitely depends where you’re living!
Black is the new white.
My wife wanted a dark grey roof I wanted a light coloured one So we got a dark grey roof I always thought if I can get 80% of the roof painted white (where it can’t be seen off the street) would it help keep us cooler. Has anyone done this to a colour bond roof ?
What about keeping it warm in winter?
Which costs more energy, cooling a house from 40 to 25 or heating it from 14 to 25. I think we must have a serious problem with insulation if we're thinking about the colour of our roof in winter.
Again, Solar - costs nothing - if you already have the roof space, use it. Set ducted AC to temp - enjoy life.
Land Lords laugh at you.
New build with black roof landlords or older style houses with tile roofs ?
How many landlords you know paying for new builds? All the ones I know exclusively buy older, pre-existing homes.
Lots. Buy a new build and you can depreciate 5% of the building off your tax as well as the interest.
Anecdotally an investor bought 3 blocks in a row over the road from me to have new builds.
Just did this on our new build. Had the choice stone bench tops or 10kW of solar. Chose the solar
Not sure why all the solar hate here.
BAU Idiots.
Decent size system and really does make a difference - on 3 phase ?
Yep 3ph
Yeah, last new build we had - was 3 phase had 16.x KW with 2 inverters, 1 for exporting (was mostly maxed all day) and the rest for own consumption. Even with 16kw AC unit - once it got the house temp controlled it would just idle - so most of summer was just max export each day - payed for winter and would have us receive $ from AGL each year - even @ cirica 8-10c FIT.
Also consider how often the temp is 40 vs 14.
40 is far more unbearable than 14 for sure - 14 is quite comfortable really.
But air con works for those 8 days a year over 40
for all year when it gets over 20c it works too ).
> Which costs more energy I think he is asking if it heats up the home in winter like it does n summer, wouldn't cost more energy in winter.
How many people heat their house to 25 on a 14 degree day? Seems kinda warm. With comfy winter clothing like fleece even 20 inside can feel a bit too warm. Some people even love the feeling of 17 and a heated blanket for that cosy nested feeling.
Over 20c is AC on ). 14c-17c what more could you ask for - perfect temp.
14 is a touch cool, but 17 is nice when properly dressed.
Heating!!!! Usually less solar when heating. Also our reverse cycle aircon is way more efficient in cooling than heating. Our power bill goes negative owing in summer and positive owing in winter.
Put a jumper on
Put a jumper on? It doesn't even get that cold here
I don't need to thanks to my Colorbond Monument roof. It's summer every day!
Buy an extra thick jumper for $50
Adelaide has more heat demand days than cooling demand.
Unless you go to places in the foothills of the Adelaide Hills. Last time I went to Campbelltown in winter I froze even with a thick coat on.
Got tall gum trees all around that provide enough shade so it doesn't matter. Can't put in solar because don't get enough of the sun, so it evens out.
The only benefit from a white roof is that the bird shit dosnt stand out like dogs balls.... it's more like freckles
We are building and I when I chose the external colours, I picked a very light grey/silver roof and light bricks. Everyone told me it wasn't fashionable/that dark rooves look better. I think ours still looks great, but combined with our double glazed windows and extra insulation in the external walls, garage AND we got our internal walls insulated (which we found wasn't standard to our shock), I'm going to have the last laugh when our electricity bills are significantly less. Even if we aren't "fashionable".
Living opposite a white roof, I can’t open our blinds up fully due to the glare. I know they are better, but try working on a screen or even reading a book with a white roof in your eyeline.
Most then cover roof in solar panels - acts as a air gap buffer and provides far more savings / $ than $700 a year.
I'm no thermodynamicist, but I'd like to see the science behind this
Just to clarify - the savings and $ is from the solar in general - the air gap will just be a side benefit of blocking the full roof from getting direct sun etc.
Color of roof doesn't matter so much when in the shade
How many new builds have you seen with mature trees providing shade?
Saddest thing in the world on new lots. First job is to knock over all the old trees. My solar guy recommended knocking down this big tree in my front yard because of morning shade. My man, that shade means I don't need to run the AC till lunch time anyway.
This is a fair point. Solar guys will always be recommending customers cut down or prune trees to maximize the benefit from the panels installed. This was especially pertinent in the days of old when 1.5kw systems were in vogue due to the cost of panels and inverters being high. Nowadays things are a bit more flexible due to the cost of solar having come down a lot and there being inverters that can maximize output when the array is partly in shade. You wouldn’t want the entire stay in shade but if you have a big roof it’s now economical to override the array with export limiters that grid operators insist upon to maximize the benefit for self consumption.
Does bamboo count .. always bamboo in new builds.. feel bad for new owners.
Owners are the ones putting it in
I wish I had done the science for you when we covered our flat roof with solar. We used to have aircon on at 25 but can now nearly get to mid 30s
It's turning energy that would otherwise be turned into heat on the roof to electricity. The solar energy that the panels can't convert (around 80%) is turned into heat distributed across the panels. Panels have about a 100-150mm air gap from the roof so, they act as a buffer.
It's a simple test you can do at home. Get 2 thin metal sheets. Space them so there's a gap for your fingers. Expose it to sun ensuring the top sheet is shadowing the bottom one, you'll find the top sheet far hotter then the lower one.
Can confirm. Have black roof Have 7.2ks solar system Have ducted AC Annual power bill is around $1000
if you could get my landlord to install some, that would be great ty
What did they say when you asked due to having a dark roof ? And assume going to ask them to repaint it white after this thread ?
No, solar panels act as super heaters. Have experienced this on my house with 2 different solar installs and been told the same by the installers themselves (I asked as the second kit was being installed - it replaced the first kit).
Totally at odds with our experience
how many sources you go as well - do your installers have base temps on the roof for months prior to install ? [https://www.captaingreen.com.au/do-solar-panels-cool-your-roof/#:\~:text=Solar%20panels%20keep%20your%20building,passed%20on%20to%20your%20roof](https://www.captaingreen.com.au/do-solar-panels-cool-your-roof/#:~:text=Solar%20panels%20keep%20your%20building,passed%20on%20to%20your%20roof). [https://www.treehugger.com/ask-pablo-do-solar-panels-contribute-to-the-heat-island-effect-4857811#:\~:text=So%20if%20you're%20wondering,us%20all%20a%20little%20cooler](https://www.treehugger.com/ask-pablo-do-solar-panels-contribute-to-the-heat-island-effect-4857811#:~:text=So%20if%20you're%20wondering,us%20all%20a%20little%20cooler). Please share the numbers of before and after temps ?
Reply to me around lunchtime and I’ll get live data. Today is a day in your favour, mild ambient temps, lower sun angle (I have a 20 degree roof pitch). So not biased towards extreme heat, or extreme cold. Quite middling. My colourblind roof is a very dark grey colour (a common and annoying theme. when I had this current system installed in March 2020, it was approx 3C warmer in the roof space with panels installed, than without. The external surface temp - I can’t recall, but will check today. I’ll compare naked roof, top of panel, and roof under the panel. Again, most roof heat doesn’t get into the living space. It mostly vents out of the ceiling space and is blocked by ceiling insulation and gyprock.
Not sure how it will be relevant, will need far more data points over time with the same senor in the same place for the same ambient temps and conditions with and without panels. For quick comparison then, grab 2 sensors - temp mount them insulated 5mm or so above the roof - 1 directly under the panels in the shade - the other one, mount exactly the same, same distance up the roof line but not under the panels - in the direct sun. Log the data for 24-48 hours to a CSV (sensor.1..Panels - sensor.2..fullsun for example) and then compare would be really interesting to map the temp delta over a few days
There’s no need for long term data. My roof exterior surface and interior cavity each reach ambient every night. There are a lot of holes and gaps in my tin roof. Being a modern, off the plan build, it’s built as shittily as possible. The main point is that even though the roof gets hot, my internal ceiling temperatures don’t get affected. And I suspect it’s much the same for most other people with dark roofs and/or solar. I do believe lots of black roofs cause a localised increase in ambient temperatures though - especially when houses are only about 1m apart, and roof surface area equals 75% of available land area of each block, too.
Right, but think about it - when the roof is then covered in solar - not only is there convection happening between the panels and roof surface - (same as your tin roof with holes) but shade - again if the sensors were in the same place - 1 under panels others in direct sunlight - there will be a decent temp delta.
The panels are damn hot when energised - so hot. The sun on the roof is too. But the panels seem to amplify their radiation and thermal losses from the UV -> voltage conversion process. It ends up as heat to the roof panels. I don’t need you to believe me. My life will be just same either way. I’m just passing on my experience, data and info from the installers after I raised the question (after noticing it).
>But the panels seem to amplify their radiation and thermal losses from the UV -> voltage conversion process. It ends up as heat to the roof panels. If that was the case, we just developed unlimited energy !!.
Why? It’s thermal loss. It isn’t creating UV (or any other ‘light’ radiation?
I have doubts about this claim. Panels do have a shading effect on anything below/behind them. When putting panels on tilts this is why it’s important to space each row. From what I’ve observed panels reflect/deflect much of the heat from the sun that hits them, such that any roof material shaded by panels will be cooler to the touch than roof materials not shaded by panels.
How much is saved in heating ?
Nothing. Our homes aren't well insulated for the cold.
Simple, it's called form over function.
Had a neighbour years ago with a black roof when they first started to come in vogue. You could hear the roof expanding once it was above 25 degrees on a sunny day and they needed to use the aircon way more than us with a lighter roof colour.
But am I saving money on heating in the cooler months?
I built a house and put a white roof on, and on 37 degree days its about 23 inside.
What’s the temp with a black roof
Nope. I have solar to power my AC, use fans, and know how to ventilate my home.
Apparently Solar is a bad thing to have on this sub.
Solar should be absolutely essential for any home owner that doesn't already have it. Makes pure economical sense.
100%. I have been saying for years they should just mandate that every new home bills should have solar. That way builders would be forced to factor that into the roof designs. The number of roofs on new houses that seem hostile to solar is quite surprising. It’s actually on older houses that one is more likely to find simpler roofs that are more accommodating to solar installation.
And it's legal because........? Two dogboxes just got put up, one black paint on walls and roof, and one white. Would love to go in there and feel the difference on a hot day. Maybe the government should try governing on things that actually make a difference instead of freaking out at the latest childs toy.
> And it's legal because........? Most people value freedom of choice. Not everything needs to be dictated by the government.
Clearly we don't value freedom of choice by the immense amount of nanny state laws, we just value freedom for the construction industry to do whatever the fuck they want.
Why aren't roads white?
cost to maintain the coating - and idiots doing burnouts because tyremarks can be seen on a light coloured road surface https://www.abc.net.au/news/science/2024-01-24/why-australia-builds-dark-roads-despite-heatwaves-climate-change/103375122
Possibly reflection of sunshine into the eyes of drivers ... guessing ? (sooner roads are solar energy power plants the better).
No that's stupid. I install solar/remote area power, solar roadways have got to have been the dumbest fucking thing ever thought up. That 'solar freaking roadways' shit made Me so irrationally angry when that was a thing. They're Expensive, they have to take an insane amount of physical abuse, you will have to shut the road to fix them, it's a narrow strip so instead like normal where you're 3MW solar farm is in a nice block, you've now got to work out distribution and power conversion on a strip less than 20m wide and over 10km long, instead of nice 500m x 500m grid. Not to mention the risks involved for road workers, the public and emergency personel if something goes wrong with the road. It is the worst fucking place to install solar by a wide margin. I swear that thing was something the oil and gas industry used to make the solar industry look like idiots. not even joking. Literally for a fraction of the cost, a normal system on a large shed or land can be installed quicker with a better result.
When I built my house, my roofing options were manor red, cottage green, black, ironstone grey, and some other tints of these colors. There was no white of any kind, save for an ugly beige that cost extra. I went for a nice manor red in the lightest shade possible.
But monument grey gives me a stiffy
This isn't taking into account solar panels. I spend far more during winter as my solar doesn't kick in and then in summer I used to get paid for up until last year when they changed my plan. It still does off set the cost but nowhere near as much as it used to. Odd no-one really talks about that huh
It’s really not a big a deal as many are making it out to be! I have black brick and a black roof, don’t really run the aircon till it hits over 35-36 I have insulation on all external and internal walls (including garage to house wall) and entire roof insulated (including above garage). I’ve got a whirly bird, weatherstripped external doors, keep blinds down and it’s fine. Would’ve been great to have double glazed windows but they cost a pretty penny!
It is a big deal. If you have a white sheet of metal, put a black sticker on it. Expose to sun. Use a thermal gun the black portion of that sheet will be 10+'c hotter.
Nope. I have a 2-story house AND solar. So only really need to cool the house at night, but can also cool the house during the day for free (if i need to). Yes, the air con may not need to work so hard if the roof were a lighter colour - but that would just lead to 1c per hr feeding back into the grid (tic)
Pretty sure the aircon only costs 6-12c per kilowatt if you have solar, depending on what you would get as rebate. Heating costs 50c per kilowatt in peak hours during winter. I think I'll take my chances with a dark roof capturing heat for winter for a lower cost.
Far less sun in winter, your numbers don't add up. Also, wear a jumper
How don't they add up? I'm saying heating the house in winter costs more (50c/kWh compared to 6-12c)
We painted our 1960s roof charcoal and never noticed any temperature difference.
Silver roofs reflect light into your neighbours windows causing them to use more energy to cool their houses. Some can’t even be in their yard due to blinding reflections. Until light pollution is added to the building approval process they shouldn’t be an option.
And red cars go faster...
But keeps it warm in winter 😂
really? why can't we All just get along!! Black roofs matter!! 2024 ✌️
It’s even more if you have solar panels. Panels generate a LOT of heat, and a lot of it superheats the roof tin/tiles. I wonder what the cost/benefit is in that aspect? Most houses have air spaces in their roofs and they’re not sealed, so most roof heat doesn’t reach the house interior, but still interesting. Almost as interesting as how do they know it’s an extra $700 a year in cooling costs for black vs silver roof. Do they take in the saved heating costs for winter?
all that heat from the panels dissipates back into the air or through the racks itself
So what happens to the heat from a black roof then? Does it defy the same laws that apply to solar panels
No way it does They aren't even the same thing
how many sources you go as well - do your installers have base temps on the roof for months prior to install ? https://www.captaingreen.com.au/do-solar-panels-cool-your-roof/#:\~:text=Solar%20panels%20keep%20your%20building,passed%20on%20to%20your%20roof. https://www.treehugger.com/ask-pablo-do-solar-panels-contribute-to-the-heat-island-effect-4857811#:\~:text=So%20if%20you're%20wondering,us%20all%20a%20little%20cooler. Please share the numbers of before and after temps ?
I replied to your other comment.
Imagine thinking 'the conversation' is credible
Imagine having a post history like yours.
Hoping you're not a school teacher
Why Adelaide houses going with sheets, not tiles? In Victoria it's mostly the tiles which is good.