After a search there seems to be different opinions.

We have just set ours for the winter and have the control set in the comfort zone. The house is 18 months old. The AE seems to run 24/7 with the lights on the three bathroom controllers lit all the time.

Should the AE be running constantly or should it just kick in when the humidity reaches a certain point. My experience of the last house ( 10 years old ) and this one so far is that it seems to run 24/7.

Interested in your experiences.

Our A/E has three modes - min, max and cycle. In the min/max mode it runs constantly, in the cycle mode it runs on for 40 mins and off for 40 mins.

Humidity is controlled by a dial you set to the outside temp & has the 'comfort zone' thingy. I believe by setting the dial you control the amount of moisture the thing is sucking from the air by controlling the settings of the valves and dampers inside the thing. There is a light with 'max condensation' or some such title that lights up when it is in full bore and goes off presumably when the air gets dry enough.

So, yes, I'd expect the thing to be whirring away 24/7 unless you've selected the intemittent cycle.

Our AE is almost silent. A friend of ours whirrs away and is quite noisy.

must be a pain inviting them 'round for a movie night then

I have heard worse noises

built our house 2 years ago. Every winter we have the same problem. Skin rashes I'm presuming because of the dry air in the house. One winter we didn't use it all, last year we used it at maximum for the winter (off completely the rest of the year). Both of us don't really know what we're doing or how to use it or really what its for.

Not even the fitter seemed to be able to explain to us how or when to use it, they all just seem to presume we know already. Could you just explain why/when/how much? and any point to them? I'd be really grateful, cheers

The air exchanger is to supply fresh air in a house that is, to all intents and purposes, airtight. At least that's the theory with modern houses. Maybe if you google the manufacturer's name you can download the manual and follow the directions there.
Also, don't forget to clean it out regularly. There is usually debris in the chamber and the filters should be washed according to the manufacturer's instructions. Also check the screen at the exit site in the house wall. I made some finer mesh ones for mine and that stopped bugs getting in.
The dry air in the winter can be easily rectified by using a humidifier. These can be free standing or built in to the furnace and are readily available at most hardware stores.

^^^ -- What he says.

If we don't run out air exchanger during the colder months we get a lot of condensation. It is a neccessary evil in an otherwise pretty airtight house.

so its freshening the air, not putting moisture in or taking moisture out then? thanks for your help by the way its a bone of contention in our house. I walk by whack it up, hubby walks by turns it off and moans about hydro bill!

It is exchanging the damp indoor air for fresh outdoor air. Many also have a heat recovery core that means that you don't swap nice warm air for nasty cold air. If you don't have the forced ventilation an air exchanger provides, you will experience condensation and increase the likelyhood of mould problems. (Unless you have the windows open all year round of course which gets a bit problematic in January)

Yes. Ours has filters that are supposed to be cleaned monthly and a heat recovery core that's supposed to be cleaned once a year; if I forget to clean it for a few weeks in the summer then the filters are pretty well clogged by the time I do so.

Ours has a humidity control too, but I've no idea what it's meant to do and it doesn't appear to actually do anything .

Sounds like ours, it never seems to click off and I can't imagine the humidity in the house is above 70%.

Correct. It does not do anything for the lack of humidity.
Depending on what type of heating you have you need a suitable humidifier. If you have forced air you can quite easily install one yourself right on the side of the plenum. If you have in-floor or radiant heat you will need a free standing one.

I open a window.

Don't the bears / mosquitos / 5 ft wolves or cougars then get in and eat you alive in your bed?