I own a small apartment block and I've used both Behr paint and other
company's paints. Consumer Reports regularily rates Behr paint as a
"Best Buy" because it's a good paint... ...for $18 per gallon.
Apartments tend to get repainted much more often than houses because
apartments are completely empty much more often than houses are. So,
when I was looking for a paint to use in my building it was important to
me that I got good hide (so that nail hole repairs weren't visible
through ONE coat of paint) and that the paint didn't spatter (so that I
wouldn't double the workload by having to deal with drop cloths. I
found that Pratt & Lambert Accolade Satin gave me the best hide in a
fairly glossy paint (satin) with no spatter at all. The stuff costs me
$55 per gallon (Canadian), but it hides very well, I don't even bother
covering my carpets when painting in the living rooms, and it stands up
well to scrubbing stubborn spots off without losing it's gloss. When I
used Behr latex paint, I didn't get nearly as good hide, and I had to
use drop cloths because there was paint spatter all over my right hand
by the time I was finished painting an apartment.
The moral of the story is: Don't go by what Consumer Reports says. Buy
ANY major paint company's top-of-the-line exterior latex paint and
you'll get an excellent exterior latex paint.
Also, all exterior latex paints will have some mildewcide in them, but
you have to understand the nature of mildewcides. Mildewcides are a
POWDER that's added to the paint. That powder is very highly soluble in
water, and it's that high affinity for water that actually causes the
mildewcide to migrate through the paint film toward moisture or even
high humidity on one side of the paint film. By doing that, the
mildewcide that reaches the surface of the paint will kill mildew and
fungii spores before they have a chance to grow.
But, a high affinity for water is a double edge sword. What happens is
that the mildewcide that reaches the surface of the paint film to do
it's job killing mildew spores also gets washed off the paint by rain.
So, the mildew resistance of an exterior paint will gradually diminish
as it's reserve of mildewcide is depleted.
Exterior latex paints will also most often use zinc oxide as the white
pigment in the paint instead of titanium dioxide. That's cuz of two
1. titanium dioxide acts as a catalyst in the chalking of paint due to
exposure to UV light. So, a latex paint that's white because it has
titanium dioxide pigments in it will chaulk more than a latex paint
that's reddish brown because it has red iron oxide pigment in it, and
2. zinc, like copper, arsenic and boron, is a natural fungicide. So, by
using zinc oxide instead of titanium dioxide, you help prevent mildew
growth on white, off-white and pastel coloured exterior paints.
So, it very well could be that the reason why there's mildew growing on
your house is because the mildewcide reserve in the paint is depleted
and the zinc oxide isn't enough to prevent mildew growth.
What I would do is use any top-of-the-line exterior latex paint, and
give the areas of the house that have mildew growing on them another
coupla coats to double, triple or quadruple the mildewcide reserve in
the paint film so that the paint stays free of mildew two, three or four
times as long. (The fungicidal effect of the white zinc oxide pigments
I too have heard good comments on Sherwin Williams Duration paint. But,
Mr. Williams doesn't make his paint from scratch any more than Mr. Moore
or Mr. Lambert does. They all buy their acrylic resins, pigments and
additives from chemical companies like DuPont and Dow, and so making
good paint is not an engineering or chemist's challenge. It's a
management challenge of deciding whether or not the latest and greatest
acrylic resin from the S. C. Johnson Wax company is worth the higher
cost or if the newest Ti-Pure titanium dioxide pigment from DuPont is
worth it's higher price. ANY paint company in the world can make the
world's best paint by buying the latest and greatest offerings that the
chemical companies are pushing. It's management's decision to decide
whether their customer base would be better served by paying more for
the ingredients, and charging more for the paint.
Hope this helps.