extractor fan with humidistat

[martyn88]

hi all, just want a bit of info on an extractor fan with a humidistat, i've got really high levels of moisture in my home and one of the remedys that has been sugested to me is fit these fans,
1st of all how do these work exactly, i get the general idea of them, but do they just come on and off automatically? or can they be wired to switch on with the light and then run untill the humidity drops ? if so do they get wired with a permanant live from an independant spur and then a switched live from the light ? if thats right then the only place i could install it is above the end the bath would i need a low voltage one for that ? also does anyone have any suggestions for a good reliable one, i've seen them with a variety of prices and dont know which is the best, thanks in advance for any replies

 

[PrenticeBoyofDerry]

The humidistat fans with overrun timers, work automatically when moisture levels rise to a predetermined level, they also come on when the light in the room is activated and overrun for the desired time, normally between 5-20 mins.
The wiring will depend on the set up you have but would be taken from the lighting circui. As the lives and/or neutrals could be looped in at either light fitting or switch plate, would determine the best method of install. A three pole isolator fan would also be required.

 

[flameport]

How they work is very simple.
When the air is humid, the fan switches on, and remains on until the air falls below a certain humidity.

In reality, this means the fan switches on when the shower or bath is used.
It also means the fan switches on when it's raining, when it's foggy outside, when condensation forms inside the fan ducting, when the air temperature inside or outside falls, when the moon is in a certain alignment etc.

Many models have an adjustable humidity sensor. This just means you spend hours every week adjusting it, only to find it still doesn't work as you expected.
Far better to get one with a switch and a timer, which avoids the humidity sensor shambles altogether.

Also consider that if your house has high levels of humidity all the time, other changes will be required as well as fitting an extractor.

 

[martyn88]

How they work is very simple.
When the air is humid, the fan switches on, and remains on until the air falls below a certain humidity.

In reality, this means the fan switches on when the shower or bath is used.
It also means the fan switches on when it's raining, when it's foggy outside, when condensation forms inside the fan ducting, when the air temperature inside or outside falls, when the moon is in a certain alignment etc.

Many models have an adjustable humidity sensor. This just means you spend hours every week adjusting it, only to find it still doesn't work as you expected.
Far better to get one with a switch and a timer, which avoids the humidity sensor shambles altogether.

Also consider that if your house has high levels of humidity all the time, other changes will be required as well as fitting an extractor.

thanks for the info, what kind of extractor do you mean ? i've got a list of things to get fitted to try and reduce the moisture levels

 

[PrenticeBoyofDerry]

If you want to prevent arseing about with humidistat, you just want one with a timer (overrun)

 

[Sherbertlion]

Or you could get a fan that is constantly running at a low level and then boosted either via humidity sensor or switch, like the Vent Axia Lo Carbon Centra or one of the Airflow models.