It’s been a remarkably cool not-especially-hot summer so far, what with Monsoon having gotten such an early start. So it’s not that big an issue so far that the Secret Lair can get awfully hot and stuffy in the afternoon and evening. But it’s still summer in the high desert so the Lair gets kind of hot and stuffy in the afternoon and evening.
I handle this in the old school manner: Open windows, ceiling fans, a window fan sucking air inside when the sun goes down, and a sit-down with a beer on the covered porch. The Lair’s battery bank is quite small, four T-105s, so leaving electrical draws on all night is not a thing I’m all that willing to do. Fortunately the 12-volt bedroom ceiling fan draws so little juice on lower settings that I can make an exception in its case, and that has made a huge difference in sleeping comfort. Plus a stick-built cabin just naturally cools off overnight anyway. Even if it’s an exceptionally warm evening, sooner or later it’ll cool off enough that you can get some sleep.
Not so Ian’s Cave.
Thermal mass, they said. It’s your friend, they said. And we went with that, back in 2009, without sufficiently thinking things through. If we’d really seriously planned the project we’d have paid a lot more attention to ventilation.
Ian’s Cave is a concrete dome buried under I don’t know how many tons of sand. It holds heat very well in the winter, and takes a couple of months to get uncomfortably hot in the summer. But once it does, there you are. The good news is that the first couple of months of winter won’t pose much of a heating problem. But in mid-summer…
…my thoughts always turn to “how can I cool this bitch down, just a bit?” I have to work in there. I deeply regret that we didn’t put some ventilation ducts and fans through the back of the dome before we shotcreted and buried it. Too late to worry now.
I can get the overall internal temperature and humidity down a couple of points by running that big fan on a timer overnight. But I have a strong emotional resistance to doing things like that. And Ian’s batteries…
…while much more substantial than mine, are also ancient by battery standards. At twelve years old, they’ve already lived more than twice the standard lifespan. I attribute this entirely to clean living: They have a caretaker who takes loving care, and they’re seldom stressed. Basically, most of the time they run a refrigerator and that’s all.
So when I start doing things like running big fans overnight, I always feel like I’m committing at least a venal sin and I pay attention to what it’s doing to the batteries.
And I always – reluctantly – come to the conclusion that I’m not really breaking any rules. The bad thing about a big battery bank is that replacing it costs multiple thousands of dollars. The good thing about a big battery bank is that it’s pretty hard to really stress if you’re not neglecting it.
In this case, every single morning without the fan running the battery charge sits pretty at 90%. Every single morning with the fan running, it’s at 82%. Which tells me I should really just relax.
But I’m deep in the ranks of the poors, and relaxation isn’t my default state. Basically I treat batteries the same way I treat puppies – I’m something of a worrywart.
