Summertime - Hot and Humid

In a much needed break from the deep thinking I‘ve been working on lately, today we are going to talk about the effects of humidity – which is seriously hindering my ability to think at all. Our current temperature on Monday afternoon in Blacksburg, VA is 88⁰ F, but the Weather Underground (www. Underground.com) site tells us that the Heat Index is 97 degrees. This takes into account the relative humidity in an attempt to determine the human-perceived equivalent temperature. HOT & STICKY.

Big Ass Fan

Not so bad when the air conditioning is working in my office, but a different story entirely in my attic apartment of an old house, which probably has little to no insulation. And though there are big trees in the neighborhood, none provide sufficient shade to the house. Since this is a rental, paying for an insulation upgrade is out of the question. This gives me great empathy for renters in the South, and makes me think afternoon siestas under a tree are a good idea. Might as well, since the humid heat induces a sort of lethargy, anyway.

Are there any good ways for natural dehumidification? High ceilings and moving air with fans is the classic Southern solution. Vents or exhaust fans next to moisture generating activities (bathroom, kitchen) is always recommended no matter the temperature, but especially in high humidity.

Traditional Air Conditioning is governed by the function of removing the sensible heat by cooling the air, as well as the functioning of dehumidification. However, these functions cannot be decoupled, so it can be tricky in a super energy efficient house which doesn’t have the necessary temperature differential to trigger on the AC unit. A separate dehumidifier is often recommended. We often hit this problem with ICF houses.

There is one company who claims to address this issue.  The Optima Air Dehumidifiers “made up of special non-chemical, non-toxic coolant and adsorbent filtration minerals that continuously (even when the compressor cycles off) removes water vapor from the air and to lower the dew point in order to prolong the stability of humidity in the air.” It appears to work in tandem with commercial AC units, and has picked up clients from Coca-Cola to Piggly Wiggly.

Unlike the adding of moisture through evaporation, removing moisture is not intuitively easy to resolve in a non power hogging way. One would need something which absorbs the moisture, and then wicks it out. This presumes that there would be some area which is dry to which the moisture would wick – but the relative humidity is pretty all pervasive.

One old-time here apparently used to hang up burlap bags of rock salt in the basement, with a can underneath to collect the water which has condenses out of the air. Another method was using charcoal briquettes to absorb the moisture (for example in a bathroom) and then periodically put them outside to dry out. Of course, the more modern version of this is silicone or clay dessicants, which the Australians have perfected. For smaller applications, there are products like Dri-Z-Air, or Well-Dry.


But the Tour-de-Force solution here was created by Patrick Ward of FossilFreedom. For all you dedicated energy geeks out there – this is the ultimate solution for a make-up air drier and heat exchanger. Check out this guy’s website.

In the meantime, I think it is time for a tall glass of ice tea, a little bit of shade, and a nice light summer novel…