Whitewash
If you Google greenhouse whitewash you will find both paint and the strategies corporations use to recharacterize their impacts on greenhouse gases. We happened to be looking for paint. Our fabulous new studio space has a big skylight that makes it unnecessary to have lights (a good thing because they’re not installed yet). But we’re having hot and sunny weather and the mezzanine team was dealing with a tropical heat wave. Having VE’d out the fabulous modern low-E or translucent glazing, and having found that the old glass won’t accept energy saving films, we thought about screens and shade cloth, and then about the whitewash growers use on their greenhouses. Researching that we found an American product that contains formaldehyde (known to cause cancer), traditional whitewash (lime), known to turn aluminum black, and a wonderful new European product that is white when dry and clear when wet. Interestingly, the manufacturer will not publish the chemical contents, and though it states that it is “non-toxic”, it also recommends not to let it drain into a sewer. To clean it off you use sulfuric acid. All in all, it sounded like the chemistry was being withheld for a reason. A competing American product also won’t publish its contents.
So we chose to apply white latex paint diluted 8x by water. We (or more properly Leo – thanks from all your cool colleagues) cleaned the skylights and rollered on two coats. The glazing had been replaced at many different times over the life of the skylight and the added uniformity helps the appearance. The heat and glare difference is radical. We still have enough daylight to do without lights but despite the hot weather the sunglasses and sombreros have disappeared and everyone is SO much happier. But wouldn’t it be great if the variable whitewash turned out to be a safe solution - it will be winter soon and we might welcome a little more sun.