Trickle vents

[JohnBishop]

Hi,

I have moved to a property that has ALL windows with trickle vents. On top of a wide ventilator in the kitchen and a smaller in the bathroom there is also an air brick in the living room for the old gas burner (removed long time ago).
This and the trickle vents on all 9 windows makes the draft like in a dog's shed. I think dog's shed is actually better.
I have already blocked the air brick but I have to address these trickle vents.
Before these windows are going to be replaced in a year or two I have to stop the draft.
Duct tape gives me mixed result because the small gap between the trickle vent cover plastic and windows frame is still leaking some air x9.

These Slotvent trickle vents cannot be removed. These are screwed in and I cannot remove the screw caps.
Should I just destroy these screw caps, remove the vents on both sides and duct tape holes on both sides and put the trickle vents back in
OR instead put some expanding foam into the holes in the window frame through the intake of the trickle vent?

 

Let me know what you think

[Nickfromwales]

The air quality and humidity will become hugely problematic if you do as you suggest. Try opening the trickle vents to 5 or 10% of their capacity and revisit.

Is this a brick and block cavity wall dwelling? Cold or warm roof?

[JohnBishop]

Hi Nick, these trickle vents have no control, fully open all the time.

I know what you mean however a single person at 84sqm does not cause that much condensation.

[JohnMo]

Why not replace with something like this.  Then they only open as much as required and do it automatically.

 

https://www.bpdstore.co.uk/glidevale-energy-saver-humidity-sensitive-trickle-ventilator/p/182

[JohnBishop]

I am a bit baffled why there is almost 10% higher humidity upstairs than downstairs? I know there is a bathroom but it has not been used while I measure the humidity.

[JohnBishop]

11 minutes ago, JohnMo said:

Why not replace with something like this.  Then they only open as much as required and do it automatically.

 

https://www.bpdstore.co.uk/glidevale-energy-saver-humidity-sensitive-trickle-ventilator/p/182

Interesting it says it's automatic without any electrical or mechanical power.

[JohnMo]

They use a material, that shrinks or expands based on humidity.  Use this to modulate the flap, simple reliable stuff that seems to work.

[JohnMo]

15 minutes ago, JohnBishop said:

I am a bit baffled why there is almost 10% higher humidity upstairs than downstairs? I know there is a bathroom but it has not been used while I measure the humidity.

Depends on the time of day you measure, if you have people upstairs they are all breathing out moisture.  Perhaps your ventilation is less well performing upstairs.

[JohnBishop]

23 minutes ago, JohnMo said:

Depends on the time of day you measure, if you have people upstairs they are all breathing out moisture.  Perhaps your ventilation is less well performing upstairs.

In my case there is no baths for a couple of days and even then the window is opened to let the excess moisture out.
I have lived in a flat before so not sure how this works. Is it possible the moisture makes its way upstairs and there always be that discrepancy?

 

I have 4 temp/humidity sensors, 1 downstairs, 2 upstairs (2 different rooms) and one outside (North side).
Two sensors upstairs are off by about 3% (59% and 62% respectively).

 

I have the display in front of me so my readings are regular not just one off.
I was just wondering if there is any of the sub floor heating or water pipes slowly dripping maybe? I have not seen any wet patches anywhere but if the rate is slow enough the sub floor dust absorbs it.

Edited October 17, 2022 by JohnBishop

[JohnBishop]

One of the sensors was on the window sill the other is a bit further away from window (2nd room). I reckon moisture level is higher closer to the window where vapour likes to condensate. I put both on the floor away from windows. Will see if there is any big difference.

Edited October 17, 2022 by JohnBishop

[MDC]

Our house is on a north/south axis. The difference in temperature at the front of the house to the back is sometimes impressive. So I bought some gadgets to measure temperature and they happen to measure humidity too. The north side humidity is higher than the south. 

 

Right now, we have 57% humidity (19.9c) south side and 67% humidity (17.1c) north side - no heating on yet.  Measuring the humidity on the window sill is always higher than by the internal wall - so there can be different measurements of humidity in the same room. Humidity is an interesting thing.

 

If I was you, I'd block all the drafts from wherever they come, as best I can. 

[Olf]

On 16/10/2022 at 23:34, JohnBishop said:

I cannot remove the screw caps

 

It will be more or less destructive: try with a tip of a blade in the gap and pry against the body of the vent. If not successful use small woodscrew acting like bottle opener

 

20 hours ago, JohnBishop said:

I am a bit baffled why there is almost 10% higher humidity upstairs than downstairs?

You mention percents, so you are talking relative humidity - relative to the temperature of air containing water vapour. That suggests you temperature upstairs is a bit lower than downstairs. Absolute humidity (expressed in g/m³) is likely similar, though bathrooms and kitchens will have it higher after use, and so bedrooms in the morning after all you breathe out.

 

19 hours ago, MDC said:

Measuring the humidity on the window sill is always higher than by the internal wall

Near windows heat is lost more easily than at the wall, the temperature locally is even lower so RH is increased for the same amount of water in the air.

 

[SteamyTea]

22 hours ago, JohnBishop said:

I am a bit baffled why there is almost 10% higher humidity upstairs than downstairs? I know there is a bathroom but it has not been used while I measure the humidity.

Try converting to absolute humidity. Probably find the mass of water is similar.

[JohnBishop]

Ok, thank you for your replies.

 

I have 4 measurements at the moment:

18.9C 51% (downstairs)

19.2C 53% (upstairs, room1)

17.6C 65% (upstairs, room2 but an opened window - some cold air and humidity is coming in, outside it's 12.3C 79%)

[SteamyTea]

40 minutes ago, JohnBishop said:

I have 4 measurements at the moment:

Run it though here, find a local WeatherUnderground station to get pressure and outside temp and RH.

 

[JohnBishop]

21 hours ago, SteamyTea said:

Run it though here, find a local WeatherUnderground station to get pressure and outside temp and RH.

 

Where can you see the pressure on WeatherUnderground?
I see Pressure but it's given as 30.27 in

From https://www.forecast.co.uk/pressure/ it's 1025

Absolute humidity, kg/m3 - 0.008 (outside)
Absolute humidity, kg/m3 - 0.009 (downstairs)

Absolute humidity, kg/m3 - 0.011 (room 1 upstairs)

Absolute humidity, kg/m3 - 0.010 (room 2 upstairs)

[SteamyTea]

3 minutes ago, JohnBishop said:

Where can you see the pressure on WeatherUnderground

In the settings.

 

 

[JohnBishop]

Ok, thank you. Yes so the number I used is correct 1024hPa

[SteamyTea]

1 minute ago, JohnBishop said:

Ok, thank you. Yes so the number I used is correct 1024hPa

It will be different now. Storm coming in (well down here anyway).

[JohnBishop]

I have removed the plastic covers from the outside.

Can I simply fill the holes with expanding foam?

Then I wanted to simply cover it with two layers duct tape and aluminium tape on top.

[Dave Jones]

house full of mould if you have no airflow.

[crispy_wafer]

Probably not a great idea, unless you have an alternate means of ventilation.

[jayc89]

Now you've ripped it off, I'd replace it with one of the automatic vents that have already been suggested. It should remain closed, or at least partially closed, when humidity is at a satisfactory level. 

Having just fitted mechanical ventilation to a house void of any trickle vents, I highly recommend you don't seal them up without some other method of ventilation to those rooms. (Over winter, even the window in our 8 year old kids room would be dripping wet every morning)

[JohnBishop]

4 hours ago, jayc89 said:

Now you've ripped it off, I'd replace it with one of the automatic vents that have already been suggested. It should remain closed, or at least partially closed, when humidity is at a satisfactory level. 

Having just fitted mechanical ventilation to a house void of any trickle vents, I highly recommend you don't seal them up without some other method of ventilation to those rooms. (Over winter, even the window in our 8 year old kids room would be dripping wet every morning)

I know but this is too expensive to fit a fancy device on every window. I don't think I need it on every window in the house. Maybe I leave one or 2 on each floor but I don't need like 10 of them.

Besides probably the screw holes do not line up and I will have to drill two more holes and it will look bad.
I want to fill the void with something then duct and aluminium tape and screw these plastics back on.

 

4 hours ago, crispy_wafer said:

Probably not a great idea, unless you have an alternate means of ventilation.

 

4 hours ago, Dave Jones said:

house full of mould if you have no airflow.

as I said I had them all blocked over the winter and no mould or humidity over 52%.
There are vents in the bathroom, a big one in the kitchen and a fire stove that most likely circulates all the air from downstairs.

Edited May 22, 2023 by JohnBishop

[SteamyTea]

Squirt foam in, easy enough to poke a hole through it with a drill if you have to.

You could get some white PVC and stick that over the holes. May look better.