Many homes are built with a vapor barrier inside of the insulation on outside walls, to prevent wintertime condensation in those walls. Such condensation would promote mold, rot, carpenter ants, etc. and eventually destroy the outside walls.
The same situation can exist in reverse in the summer. If the indoor temperature is lower than the outdoor dewpoint, outside humidity can condense within the walls. It is not wise to install a second vapor barrier to protect against this, as the wall could never dry,
A simple solution is to provide a low limit to the cooling temperature, that will automatically adjust so that the setpoint cannot go below the outdoor dewpoint.
I’d recommend displaying something on the thermostat user interface during the times that the limit is in effect. If you provide an override to disallow this feature, also provide a red warning on the thermostat user interface during the times that this condition exists.
The benefit to your customers would be to protect their expensive homes from one source of mold and rot.
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