On 2 May, 12:22, Stuart Noble wrote:

The whole concept is flawed in my view. You're simply sucking in air
from outside through the air bricks. Sure, you'll create reassuringly
large amounts of water but it won't make the cellar any drier.

My cellar is drier with a dehumidifier than it was before. I keep some
tools down there, and they no longer develop the slight coating of
rust that they used to. I take the point about it not being wholly
efficient unless it operates in a sealed room. But the same logic
applies to running the central heating - why bother, all the heat only
ends up going through the roof in the end?