On 28/12/2017 01:20, T i m wrote:
If it leaks humidity we may have to run the de-humidifier
and that reduces the efficiency a bit?

AFAIK they all leak humidity.

I'd design it with a closed cycle air system. They don't seem to do that
- they heat fresh air, then cool it again on the way out to extract some
of the moisture. Not all of it.

Andy