Its been in the US news that we can help save the planet by painting our roofs white. Seems like other countries have known this for ages.

There are already places that specialize (http://www.coolroofcontractor.com/) in it. Is this a good idea or has it been blown out of proportion? Other cultures do it, why is it shocking to suggest Americans should just paint their roofs?

http://farm1.static.flickr.com/44/134909781_125019ef1c.jpg?v=0

how exactly will white painted roofs help and with what? the greenhouse effect?

I am guessing it is because of reflectivity of white, right?

It depends on the temperature differential: outdoor vs. indoor.
White is a poor radiator so if it's warmer inside then the heat loss will be lower - lower heating bills since you aren't paying to heat the atmosphere.
Alternatively, if it's very sunny (not just hot) then the heat transfer to indoors will be low (reflecting a lot of the sunlight) making it cooler indoors than outdoors in direct sunlight (presumably that's why it's done in places near the equator).

yo the best idea would be to have solar panels generate electricity on every roof of every city

I don't think there are white asphalt roofing shingles available. Every thing else is expensive. It would also discolor rapidly.

I don't think there are white asphalt roofing shingles available. Every thing else is expensive. It would also discolor rapidly.

But even a lighter colour would be better right?
Here in MI we tend to go towards darker colours because it absorbs sunlight in winter. Our roof is dark green.
We have stuck to a gravel driveway vs asphalt because of the heat though. I didn't want dead grass/plants all up and down my driveway

I suppose. I'm about to get a new roof, and presently the house gets much hotter than the ambient air temperature during the day. Some of that has to do with lack of insulation.

White painted roofs would make a lot of sense in Florida, along the Gulf Coast or across the Southwest--it's not called the blazing Southwest for nothing...:)

yo the best idea would be to have solar panels generate electricity on every roof of every city

Yup - that should be law.

White is good during the summer time but come winer you would want something to absorb the suns heat, a darker color would be better then.

White is good during the summer time but come winer you would want something to absorb the suns heat, a darker color would be better then.

It would keep the housepainters busy, anyway...:)

Don't they have paint that changes colours?

Whaaaa... t? And reflect all that free solar electric and hot water heater energy back into space instead of using it to reduce electric and gas bills?

Even southern climes have cold spells, and solar heating goes a long way towards reducing those electric bills.

Speaking of which, if you're reflecting all that energy back into space, then turning around and heating the unit anyway, there's absolutely no gain.

On the other hand, if it's summertime, then reflecting that heat upwards makes sense.

But you still need hot water... :)

Yup - that should be law.
The problem is the energy required to manufacture that many solar panels vs the electricity you get in return may diminish over time. Solar water heaters on the other hand are great, I've seen these installed up close and they produce hot water even on overcast days. Better than using any electricity to generate heat.

http://www.navitron.org.uk/product/thumb/additional/1252653356_l_116.jpg

But it also has similar drawbacks as with electricity generating panels, but are a little more efficient.

Yes there are white shingles how ever it only takes a few years for them to turn Grey and look really really ugly. Just imagine housing in a million dollar plus subdivison looking like something from downtown detroit when it comes to the roof. Not likely to happen unless it is mandated that it has to happen and then there would be the cost factor who pays for it the owner or the government forcing the owner to change the colour of the roof.

And the problem with Solar pannels is the return on investment it is way too long for the average home owner to invest 20 to 30 plus on panels and connecting harware that is only rated to last 15 years when the return on the investment is between 5 to 10 years. And then there is the issue of a land owner that has multiple buildings things like this could cause a large problem very very quickly.

Yes there are white shingles how ever it only takes a few years for them to turn Grey and look really really ugly. Just imagine housing in a million dollar plus subdivison looking like something from downtown detroit when it comes to the roof. Not likely to happen unless it is mandated that it has to happen and then there would be the cost factor who pays for it the owner or the government forcing the owner to change the colour of the roof.

Mine were a light grey when installed several years ago and have been bleached by the sun so that they are actually whiter now. (I don't live in or near a city.)

Don't see your problem with who pays. Just install the whiter ones when your next replacement is due. That would get a fairly large number of them done every single year. 10 years would probably see 50% converted.

Mine were a light grey when installed several years ago and have been bleached by the sun so that they are actually whiter now. (I don't live in or near a city.)

Don't see your problem with who pays. Just install the whiter ones when your next replacement is due. That would get a fairly large number of them done every single year. 10 years would probably see 50% converted.

Well yours are likely whiter because you do not live in a city and many cities are much worse then others. And 50% of the roofs replaced in 10 years not likely considering the average min live is 15 years on shingles and can go as high as 40 which I personally have on my own home so I would be in me 90's give or take before that roof needs replacing baring natural things like wind or hail damage. in 10 years you would be lucky to see 10 percent replaced and a lot would not get replaced as the owners cannot afford or will not afford replacement due to either rental or personal reasons so yes. A mandated replacement of the roof's would have to involve government funding period.

Well yours are likely whiter because you do not live in a city and many cities are much worse then others. And 50% of the roofs replaced in 10 years not likely considering the average min live is 15 years on shingles and can go as high as 40 which I personally have on my own home so I would be in me 90's give or take before that roof needs replacing baring natural things like wind or hail damage. in 10 years you would be lucky to see 10 percent replaced and a lot would not get replaced as the owners cannot afford or will not afford replacement due to either rental or personal reasons so yes. A mandated replacement of the roof's would have to involve government funding period.

Actually, I was considering the average life-span to be 20 years when I said 50% in ten. (That's a *very* simple application of statistics.) But if it's closer to 15 years - as you say the average is - then it would take even less time. So I still do not see your claim about paying as being a major issue at all.

Those with 40 years, such as yours, are so far from the average that they wouldn't be worth counting. Metal (steel) roofing is becoming more popular in the U.S. every year, too. It's available in white, has a long life, and could be repainted with a boom truck (spray-on enamel) in less than two hours every 20 years or so.

I've had ...

http://4myroof.com/wp-content/uploads/100_0856.jpg

On my roof for over 50 years now and they do a good job in the summer and winter. They aren't to bright to reflect all of the heat away yet not to dark either to absorb heat. Having a clay tile roof is the best way to go I'd think for the tiles last a very long time and serve a duel purpose as well.

I've had ...

http://4myroof.com/wp-content/uploads/100_0856.jpg

On my roof for over 50 years now and they do a good job in the summer and winter. They aren't to bright to reflect all of the heat away yet not to dark either to absorb heat. Having a clay tile roof is the best way to go I'd think for the tiles last a very long time and serve a duel purpose as well.

A caly Tile roof is good for temperate climates but in Canada the freeze Thaw effect can shorten the life of a Clay Tile system drastically. When I was younger I used to do Roofing during the summer to help pay for schooling I have several Brothers currently in the industry and they say the same thing clay tile is not a really good solution for the Canada climate.

Actually, I was considering the average life-span to be 20 years when I said 50% in ten. (That's a *very* simple application of statistics.) But if it's closer to 15 years - as you say the average is - then it would take even less time. So I still do not see your claim about paying as being a major issue at all.

Those with 40 years, such as yours, are so far from the average that they wouldn't be worth counting. Metal (steel) roofing is becoming more popular in the U.S. every year, too. It's available in white, has a long life, and could be repainted with a boom truck (spray-on enamel) in less than two hours every 20 years or so.

You would be surprised as to the average there are more and more people getting thew 40 year life span shingles then you may think I asked my Brother who has been in the industry for over 30 years and he says most new homes that are built they are the ones receiving the 10 to 15 year shingles Replacement roofs are between 20 and 40 year shingles as the price point is minimal for the extra life span of the shingle so too discount the above 20 year in the stats is Folly at least in the area I am from.

A caly Tile roof is good for temperate climates but in Canada the freeze Thaw effect can shorten the life of a Clay Tile system drastically. When I was younger I used to do Roofing during the summer to help pay for schooling I have several Brothers currently in the industry and they say the same thing clay tile is not a really good solution for the Canada climate.

You're right - not only do they breath too much, but snow/ice buildup can backup under the tiles, lifting them. Water encroachment can be a problem if they're not installed over standard sheeting and barrier roofing.

They're great for SoCal, where it's not blatently hot, but where you don't have to worry about snow, either. Not so good for hotter climes like Vegas and Phoenix, unless you substrate them with a thermal reflector (generally perforated alumunium clad to the fiberglass attic insulation).

I looked into this before I got my roof done, and it's not practical. There are no monetary savings for the homeowner, it only helps cities act less like heat islands, and even that won't work unless everyone does it. If you want to pay for metal, that's fine, it will last longer.

It seems that the roof is already worn that need a total repair of the roof. The roof is quite better if you can use a metal roofing material.

um..propanel comes in white..

i have propaneled many houses here in new mexico..i did my own..love the stuff..

cool roof