The one degree rule – mythbusted

The one degree rule – mythbusted

The above statement may come as something of a surprise to some, who for years have been told that the pool hall air temperature must be maintained 1ºC higher than the pool water temperature or you will suffer from condensation. But its just not an accurate fact.

It is possible to maintain the air temperature comfortably below the pool water temperature and still not get condensation on the windows. You will get a slight increase in evaporation from the pool, but your system should be designed to easily cope with this.
Issues arise when you have a heat-pump based dehumidification system, as these systems are already more expensive to operate than a controlled ‘fresh air’ system with passive heat recovery.
However –  this where you can detect where the industry ‘rule’ about maintaining the air 1ºC higher than the water temperature came from – if you lower the pool hall temperature heat pumps become even more inefficient because they are designed to take air at certain conditions in order to operate efficiently. Under these circumstances you will not be able to lower the air temperature without detrimentally affecting the performance of the heat pump unit.
This is not the case with controlled ‘fresh air’ ventilation systems which can cope with lower air temperatures providing they have been sized correctly for the project.

Pool side staff will appreciate a lower temperature as it makes their working environment become more pleasant to work in.

See the attached paper for greater Technical detail