> I noticed that someone had placed an oscillating fan inside the ductwork, just before the indirect heater. “What’s this for?” I asked the plumber.
> “I’m trying to blow the heat upstairs,” he said. “It doesn’t seem to be working, though, and that’s what’s got me stumped. Heat rises.”
> “Actually, it doesn’t,” I said. “Hot air rises.”
> “Well, same thing, right?”
> “Not exactly,” I said. "Hot air will rise, but only if cold air can take its place."
> “I don’t get it.”
> “Come here; I’ll show you.” I followed the large sheet-metal duct back to where it met the foundation wall. “Where does this go?” I asked.
> “Outside,” he said.
> “Where outside?”
> “I don’t know,” he said. “I don’t do outside. I do inside.”
[...]
> I waded into the greenery and stomped around on it for a while. “The gardeners aren’t going to like that,” the plumber said.
> “It’s okay,” I said. “I do outside.”
> And that’s when my stomping made a hollow sound. I smiled. “Got a shovel?” He went to get one and I waited, and while I waited, I thought like air. If I were air, how would I get into this house? He came back in a few minutes and handed me the shovel. I dug down about six inches and hit plastic. Clear plastic. I moved some more of the dirt out of the way and saw the metal bars of the old air-inlet grate.
[...]
> When the gardener showed up, I explained what we were doing and how the air wouldn’t move across the red-hot indirect heaters because there was no fresh air coming into the house. He understood but then explained how ugly those ground-level grates were and how they had decided to cover them all with sheets of clear plastic, topsoil and pachysandra. “That’s why the house is cold,” I said.
> The gardener pointed to the plumber. “It’s his job to keep it warm. It’s my job to keep it green.”
> “The problem’s outside,” I said. “He doesn’t do outside. You do.”
> And we went back and forth like that for a while until the gardener reluctantly agreed to remove one of the clear plastic sheets, just to prove me wrong.
Clearly, the ultimate fault lies with the original architects, who unfairly designed a heating system that existed both outside and inside the house. But it's also interesting to note that the plumber's entire job was to understand how the house worked, and not only did he not understand it, he didn't seem to feel there was any reason why he should understand it.