Painted white roof drops house temps 8-10 degrees

[lucerne96]

A cheap & easy solar heat blocker is to make an exterior storm window from 1"x2" stock, and stretch over it a solar emergency blanket. Tape the edges down, install with the reflective side facing out. This system costs about $10 per opening.

[Mobile Master Tech]

Here is my solution that I and my HOA was happy with:



Landmark EnergyStar rated asphalt shingles by Certainteed in Silver Birch color. This is the only 25%+ heat reflective asphalt shingle that isn't white or $$$$$$$. In fact, this was a no additional cost upgrade. Most shingles only reflect 3-8% of heat.

On a 93F sunny day, my old shingles were 159F, the underside of the roof deck was 136F, the top of my R30 blown-in insulation was 118F, and the ceiling side of my drywall was approx 88F.

Before replacing the roof, I put a sample patch up. On a 70F mostly sunny day, the old roof was 144F while the new shingles were only 124F!

I haven't gone back up there to test since the weather is warmer, but on a couple of 90F days, the ceiling is within 1-2F of room temp, and downstairs rooms with sun coming in them are much hotter than upstairs rooms without sun!

Note the Crepe Myrtles shading the walls, windows, door & garage door. This photo was taken around 6pm.

[Mobile Master Tech]

Temp test on 70F day. Old roof:



And new roof:




The whole house pic doesn't do it justice due to low resolution. It is a very pretty light gray with some visual texture to it. A poll of my neighbors showed that most preferred it to the color of my old roof.

This was the first solar reflective roof my roofer had done. His comment when we were on the roof together inspecting the job? "Wow! It actually feels cool up here! Most roofs you just feel baked from below."

Can you say "improved PV array efficiency?"

[Exalta-STA]

That looks promising! You made me wanna try and photoshop if my house looks good with a white roof

[Mobile Master Tech]

It's actually a pleasing light gray. Wish the picture did it justice. Most white roofs are very... well, WHITE, and they tend not to stay that way. You're welcome to come look, but it looks like your trip would be a bit long!

Many home improvement stores have a large sample patch installed on the wall and smaller sample boards you can take home with a deposit. Since you aren't in the US, the specification you are looking for is "Initial Solar Reflectance". Energy star criteria are that this number must be at least 0.25 and maintain 0.15 SR after 3 years. Mine are 0.27, higher is better.

Landmark Solaris Platinum shingles from Certainteed have an ISR of 0.40 but are $$$ because of higher cost per square and more bundles to cover 1 square.

[Exalta-STA]

Hahaha the tickets for the trip would cost me my whole 401k

I saw some sold here at Home Depot and at Ace hardware...I was just passing by so I wasn't able to ask the specs on it and how to attach it and if it'll stand u to 100kph winds since typhoons hit this place 20-30 times a year.

But that color looks a lot lighter than the one on my sheetmetal roof..so i'm quite sure that it's gonna be effective like you mentioned

[Mobile Master Tech]

When installed as recommended by Certainteed(details on their site) they give a 110mph wind warranty on Landmark shingles and 130mph on Solaris and others. Homeowner's insurance also covers wind damage.

Metal roofs almost always are more thermally reflective, but many don't like the look/cost/rain noise. I'm required by my HOA to use asphalt shingles.

Craig

[TimJFowler]

Craig,

It's good to see how much cooler your new roof is and how well it fits with the house and neighborhood.

Originally Posted by Mobile Master Tech

Metal roofs almost always are more thermally reflective, but many don't like the look/cost/rain noise. I'm required by my HOA to use asphalt shingles.
Craig

FWIW, We have a 'galvalume' metal roof which fits well with our house and in our neighborhood (no HOA either). We don't notice much rain noise at all, though that may be due to the R-50 of cellulose insulation in the attic.

Tim

[TimJFowler]

FYI - Here's another study on white roofs - The long-term effect of increasing the albedo of urban areas. Researchers at the Concordia University Heat Island Group in Montreal estimate that painting 1% of the world’s urban surfaces white (rooftops and pavement) could reduce CO2 emissions by 130 gigatons over the next 50-100 years!

One more reason to Paint it White.

Tim

[S-F]

Just thought I'd toss this in there:

The Science: Why Radiant Barriers Don't Work in Connecticut