Hi
I’ve been looking into VapourFlow humidity control WAD units (‘Warm Air Dehumidifier’), as I’ve been reading a book about damp houses that talks about them. It claims that they don’t just run as a normal extractor fan or heated PIV (‘Positive Input Ventilation’), but that they actually sample air from both inside and outside the property, compare humidity values, and then choose the drier source to supply/extract.
Basically it was described as follows: the unit samples outside air by pulling it into the house and passing it over a thermo-hygrometer sensor/chip, then it reverses the fan to sample air from inside in the same way. It compares the results and records the best source of dry air.
The book says it only extracts air if the humidity indoors is high, and it only brings fresh air into the house if the humidity of the outside air is low. It says it only powers up when a difference in air moisture is detected, as there are times when just doing nothing is actually best.
I haven’t been able to find any documentation from VapourFlow themselves confirming whether this is really how the system works though. The info on their website seems to suggest it uses a simpler threshold control (e.g. a sudden humidity rise indoors triggers a period of extraction, and the rest of the time it defaults to a continuous PIV function).
Does anyone here know:
I’ve been looking into VapourFlow humidity control WAD units (‘Warm Air Dehumidifier’), as I’ve been reading a book about damp houses that talks about them. It claims that they don’t just run as a normal extractor fan or heated PIV (‘Positive Input Ventilation’), but that they actually sample air from both inside and outside the property, compare humidity values, and then choose the drier source to supply/extract.
Basically it was described as follows: the unit samples outside air by pulling it into the house and passing it over a thermo-hygrometer sensor/chip, then it reverses the fan to sample air from inside in the same way. It compares the results and records the best source of dry air.
The book says it only extracts air if the humidity indoors is high, and it only brings fresh air into the house if the humidity of the outside air is low. It says it only powers up when a difference in air moisture is detected, as there are times when just doing nothing is actually best.
I haven’t been able to find any documentation from VapourFlow themselves confirming whether this is really how the system works though. The info on their website seems to suggest it uses a simpler threshold control (e.g. a sudden humidity rise indoors triggers a period of extraction, and the rest of the time it defaults to a continuous PIV function).
Does anyone here know:
- If VapourFlow WADs (or similar systems) truly operate by comparing absolute humidity inside vs outside,
- Or whether they just monitor internal humidity and react when it spikes?
