How well does latex interior paint hold up to being stored in a hot garage over time? I did some painting several months ago, and without thinking too much about it kept the leftover paint in the garage. Outside temperatures sometimes reach 90+. Should I worry about the color changing, etc.?
Update: The paint color was indistinguishable from the original. In fact, I have used the same paint again more than a year later.
Best Answer
The final color of the paint depends on the ratios of the different pigments in the paint, and those ratios won't change once the paint is mixed. The storage instructions on all the interior paints that I have say nothing about high temperatures, just to protect from freezing which I believe would cause the paint to de-emulsify.
That said, a paint can's lid doesn't form a perfect seal, and higher temperatures are going to cause volatile chemicals (including water) in the paint to evaporate faster than normal. (I've noticed that paint that has been left open for a while and thinned with water behaves differently than a can of fresh paint -- I can't define exactly how, but it just doesn't paint as well). However, given that it can take weeks for a coat of paint to cure fully under normal household conditions, if the can is sealed well, my SWAG is that it would take years before you'd notice a change in the paint.