Kitchen window humidity fan

[Brunel]

Hello, I need some advice regarding ventilating my studio flat. I am looking for a humidity tracking fan that can be installed via a kitchen window. I live in an area of high humidity all year round so it has to be able sense a slow build of RH as opposed to a rapid build up humidity from cooking (I was considering the Greenwood OL100). I have a dehumidifier however this is proving expensive to run, particularly as in summer it will be on 24/7. My flat is electric heated so a fan that doesn't create too much draught would be ideal. I am finding the dehumidifier helps to hear the flat in winter time, so I could turn the fan off during the winter months.

Additionally I have mosquitoes breeding in a sewage works next to me, so I need to avoid opening any windows and am looking at buying some insect mesh for the air bricks.

Can anyone help? Many thanks

 

[Aragorn84]

Why is a rapid build up a bad thing?

If the humidity is high the fan wants to run, regardless of wether it built up slowly or quickly due to cooking.

I would imagine you want to address the issues that are introducing lots of moisture into your flat, such as clothes drying indoors, and ensuring your bathroom has an adequate fan with timer run on.

 

[ban-all-sheds]

Brunel

Joined: 17 Feb 2015
Posts: 1
Location: United Kingdom

 

[Brunel]

I was told by Greenwood that the fan below would not pick up a slow increase in humidity overnight, say from 38 RH at 12am to 53 RH at 8am. It would only detect a large spike caused by cooking.

http://www.greenwood.co.uk/product/30/555/omnique-multifunction-fan.html

I have bought a Greenwood SF90 centrifugal, single speed humidity extractor fan for my internal bathroom - I made the mistake of having a Vent-Axia humidistat axial fan installed and now realise its the wrong type of fan. I have had a shower door fitted which contains the moisture, which was going all over the bathroom with a shower curtain. I'm hoping the new fan will help to ventilate the bathroom area better.

I only dry my clothes indoors during winter, and have the dehumidifier on at full power next to them, which drys them pretty well!

 

[EFLImpudence]

I was told by Greenwood that the fan below would not pick up a slow increase in humidity overnight, say from 38 RH at 12am to 53 RH at 8am. It would only detect a large spike caused by cooking.

How were those figures obtained?
I do not really know why a slow pick-up would make a difference but if set to 45% why would it not start?
Having said that, if set to 45% I would think it would rarely stop.
Outside here tonight the humidity is 92%; it's not raining.
Bathroom fans are usually set at around 80%.
On the other hand, is 53% in the morning anything to worry about?

I have bought a Greenwood SF90 centrifugal, single speed humidity extractor fan for my internal bathroom - I made the mistake of having a Vent-Axia humidistat axial fan installed and now realise its the wrong type of fan. I have had a shower door fitted which contains the moisture, which was going all over the bathroom with a shower curtain. I'm hoping the new fan will help to ventilate the bathroom area better.

Only by drawing air from the other rooms and eventually from outside.

I only dry my clothes indoors during winter,

Isn't that the worst time?

and have the dehumidifier on at full power next to them, which drys them pretty well!

Do you have a more fundamental problem?
Where is this area of high humidity?

 

[ericmark]

I do not have any fan but do measure the humidity in my house and outside. In the summer my house can hit the low 60's but in winter around 35% out side lowest is around 45% and meter does not measure over 95% but the important thing is the dew point as the relative humidity changes with temperature the dew point does not. In winter the dew point in the house is 7 ~ 9°C in summer it rises to around 16°C where I live in the house.

Although the temperature may rise and fall and with it the relative humidity will also rise and fall the dew point remains reasonable static.

So to dry out the house you want the drier air from outside at the moment outside here the dew point is 3.2°C and RH 88% and warm it up to inside temperature at the moment 21.3°C and the same amount of moisture would now read 10% RH where the existing air is 32% RH. The problem is of course you have to heat the air from outside.

There are units which actually heat the air coming in from the air going out clearly they will not recover all the heat but will recover some of it.

Where the problem arises is to work out if worth the money. I used a vented tumble drier and I considered the cost of pushing all that hot air outside. But the cost to heat the replacement air will be rather small compared with the cost of a heat recovery unit.

But it is often far easier to stop the moisture getting into the air than removing it once it is there. Very simple ideas like my wife and I shower one after the other so bathroom dries out once a day not twice. Closing the bathroom door and opening a window will dry out bathroom without making rest of house damp. Do not hang out wet cloths in the house dry them with a tumble drier so moisture is sent directly outside. In the old days of an airing cupboard often vented into loft so dampness did not get into the house.

Living in a caravan taught me to stop moisture getting in rather than try to dry out after. We had an awning and removing wet cloths in that before going in caravan kept caravan dry. Same with heat. Having a fan to take the heat of the fridge outside kept the caravan cool forget to turn it on in the morning and no amount of opening windows would cool the caravan down again.

So you may think a tumble drier is expensive to run but I bet it's far cheaper than running a dehumidifier and drying cloths in the room.

OK there are exceptions when in Hong Kong I had a 40 foot container with a curtain down the centre and a fan heater and air conditioner and rows of hangers for out cloths. The air was heated and blown around in a circle ending up at the air con which removed the moisture and there was a content stream of water running from the air con. All the workers would stand under to hose as they came out of the tunnel and wash off the iron ore then hang the cloths after wringing out in the container and they would be dry for next shift. With a RH of 95% and temperatures of 30°C that was the only way to dry so many pairs of overalls.

But we live in UK with temperatures rarely above 20°C and RH far lower than Hong Kong. Those methods are not required here. A simple tumble drier is all that is required or a washing line in the car port. (Wish I had one)

 

[Brunel]

Thank you for the responses, I don't have room for a tumble dryer in my flat unfortunately. I have a humidity gauge which I can use to measure the RH, not sure how accurate it is though. I am next to a sewage works so bringing air into the flat is a no no as it will smell. I do have an aerooac ventilator which brings in fresh air, perhaps I need a carbon filter to go with it?

 

[Aragorn84]

If you fit a fan to extract air, where do you think the replacement air comes from if not from outside?