Painting house exterior - RESENE coolcolour technology!

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Wannabe Geek

#270435 9-May-2020 20:56

We need to paint the exterior of our house. Has anyone tried the RESENE Cool Colour technology paint? What was your experience with it? We quite like a blackish blue colour in this range. Would appreciate any advice.

timmmay

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#2479962 9-May-2020 21:16

Resene is good quality. I use Dulux, mostly because a friend works there, and I've had good luck with it.

Darker colors obviously keep more heat in, risking the paint failing faster. Also, the more reflective it is the more heat is reflected, so don't get matt if it's offered.

What kind of wood are you painting? I have painted cedar weatherboards, I had to use an oil based primer / sealer because nothing else would stick - Dulux 1 step oil base.

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Gordy7

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#2479965 9-May-2020 21:18

Given you want to use darker paint, check out the solar reflectance is suitable for your building materials.

Resene Cool Colours are supposed to be better for solar reflectance than regular paints.

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mdf

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#2479970 9-May-2020 21:42

The theory (marketing?) behind it is that the black tint is replaced by a different type of tint that reflects the infrared while absorbing the visible spectrum - i.e. less heat is absorbed. You do have to use a white base coat behind it for most (?) colours (Resene QuickDry is recommended). In theory it may keep the house cooler, and prolong the life of the paint.

I'm painting my house at the moment and using it. It doesn't seem any different to the non-cool colour equivalents I've used in terms of ease of application, coverage, depth of colour etc. (which is good).

I'm not entirely sure on the house cooling point. That probably has more to do with things like windows and roof than walls. I suspect any difference in IR reflectance wouldn't make a noticeable difference in house temperature. And I doubt anyone has a house painted colour X with normal paint, that then repaint in the same colour with cool colour to really advise one way or the other.

But assuming the science is sound (and Resene is a reputable company) I can certainly believe that colour X in cool colour will be more durable than the same colour X in the normal equivalent though. The colour we chose was available in cool colour and the small increase in price seemed worth it. That said, as I understand things like light reflectance values (LRV), a white house in a normal paint will still reflect more light (even in IR) than a black house using cool colours.

So if you are really sold on a dark colour, I would definitely go cool colour. But personally I would still go with a lighter colour for durability, but if you can get it cool colour it might be worth the extra. If you've picked a light colour that you can't get in cool colours, I wouldn't pick a darker colour in order to get the cool colour equivalent.

There are some slight differences in colour between normal and cool colours. This was more noticeable in one of the colours we tried than the others (so far as I know, all Resene test pots are normal paint). Just something to watch out for.

MarkusY

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Wannabe Geek

#2480082 10-May-2020 08:18

^This sums it up perfectly. I would add that some CoolColors can't be made in 10L pails, and buying a house lot of paint in 4s gets pretty expensive. Most don't actually require a white undercoat to work, there's only a handful of colours that this doesn't apply too, Black and Nero (almost black) being the common ones that do. However, a full-prime is never a bad idea!

Just be aware a dark paint is still going to get hot, even in CoolColour. It will help reduce heat related issues on the cladding, but it may not eliminate them, especially if it's only ever been painted in light colours before.

We normally recommend clients don't use darker colours on timber weatherboards, but unfortunately their specified use on Linea type cladding has made it quite a common request.

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#2480089 10-May-2020 09:02

Slightly off-topic, but I've seen a new Totalspan shed built near me, and the entire thing is black, all doors, all trim. It's a big black box.

First thing I thought of is those people either don't realise just how hot it's going to get, or they can't feel temperature haha.

I had a new shed built a couple of years ago (Totalspan), and even with very light coloured walls and a darker grey roof, I've measured temperatures of 50 degrees under the peak of the roof on high 20 degree days. I'd hate to see how hot the black box gets.

JayADee

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#2480960 11-May-2020 10:03

I'm using a darkish grey on the timber window sills and fascia, couple doors, no issues.

timmmay

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#2481509 11-May-2020 21:09

I had dark blue Dulux paint for about five years. It lost condition more quickly than lighter colored paints.

Hammerer

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#2481517 11-May-2020 21:32

We are using Resene Cool Colour because we wanted to use blue (Astronaut) and the hottest area is a north facing wall with a concrete driveway reflecting more light and heat onto it. The Cool technology does make a measurable difference but, from memory, it is only about like 10% compared with having a light colour. That doesn't seem like much but we found it was possible to feel the difference with black and dark grey paint. Just get two test pots of the same dark colout, one with Cool and one without, then see if you can tell the difference.

We will still have to repaint the northern wall twice as often as the east facing wall which only gets morning sun.

Our previous paint job lasted 25 years partly because it was a paper white colour. For this reason we are continuing to use the same colour out back. That is a west-facing rear wall that gets a lot of afternoon sun and much of the dominant northwesterly wind.

Edit: I should have said that our painter friend recommended it. We're happy we paid the extra which was only for that northern wall. Nobody can pick any difference between the colour with and without Cool.

JayADee

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#2483193 13-May-2020 21:56

JayADee:

I'm using a darkish grey on the timber window sills and fascia, couple doors, no issues.

To clarify I mean we're using the Resene Cool colour version of the dark grey.