As it happens, the heating engineer was over this morning to check the filters. He noticed it was a bit warm and stuffy so he rang the air-conditioning company to ask how to fix the problem. After a few minutes' worth of conversation the engineer passed the 'phone over to Seth.
"Here, you have a go, I can't make head nor tail of it.""Well," protested Seth, "if you can't make head nor tail of it what makes you think I'll do any better.""I'm the heating engineer, I've no idea how your air-con plant works."
Anyway, between them they seem to have had a go at something. The air's no cooler but it feels a little less stale now.