PIV or humidity fan?

[Lys123]

Hi guys
I have an issue in my kitchen that a surveyor says is a failure in my damp proofing & my damp man says is only moisture. Its in one corner of my kitchen and 3 sets of solid oak worktops have bowed. Its now starting to make my metal fireplace in the adjacent room go a little rusty. Its been suggested to me to fit either a PIV or humidity extractor fan in the kitchen (one that switches on when it's humid).
I'm going to order a humidity gauge to see what it registers but which would you guys fit? What are the pros & cons to consider?
Thanks

 

[foxhole]

You have a damp man?

 

[ericmark]

The major problem with many homes is we have fitted sealed doors and windows, plus double glazing, and often blocked up vents, I remember my parents house with steel window frames with holes in bottom to outside, and the water would condense onto the window, run down it, and through the holes outside.

Clearly don't want to return to that, but you need to step back and consider where the moisture is likely coming from.

Cooking does produce moisture, but the amount with an electric cooker is small, but with a gas cooker, it is not only from the cooking, but the gas turns into water, as does any fuel when burnt, every gallon of petrol burn produces a gallon and a half of water.

So you need to look at removing the moisture before it gets into the room, the cooker hood for example with electric carbon filters can be used, but with gas, needs to be vented outside.

I know I do washing in the utility room, which is not heated, so the window is left open, and the tumble drier pipe goes out of the window, but many do the washing in the kitchen, it does not need much of a leak, for water to build up, in our flat it must have been a drip a minute, no more, but it was running under the laminate floor, so no air movement to dry it out once under the floor.

I have a meter giving relative humidity at moment 56% with is low, but run the AC and it still fills the bottle with condensate water. The portable AC can be used to cool or de-humidify, so would seem good idea to have one which can be used as required, but I would look for leaks, and life style, also check air bricks, number I have found filled with expanding foam.

 

[Groovejet]

Improve air circulation in house.
We install whole house ventilation units . Cheap enough , easy to install in the loft , locating the vent on landing ceiling . We fit them in Landlords property’s, because tenants don’t look after the homes like they would if it was theirs.
So the unit cleans the air in house, they seem to do what they say they do...in keeping homes damp free, condensation free.

 

[Harry Bloomfield]

You have a damp man?

He fell in the canal, on route to the OP's address.

 

[Harry Bloomfield]

I have a meter giving relative humidity at moment 56% with is low, but run the AC and it still fills the bottle with condensate water.

Why would it not? There is almost always moisture in the air, which is able to condense on cool surfaces.

 

[Harry Bloomfield]

Its been suggested to me to fit either a PIV or humidity extractor fan in the kitchen (one that switches on when it's humid).

I would suggest that you need to locate the cause of the moisture and find ways to reduce them. Don't boil potatoes without a lid, fit a lid and gently simmer. Fit an extracting cooker hood, so all the moisture is extracted outside. Don't hang wet clothes indoors to dry, or use a dehumidifier in the room with the clothes. Fit an extract fan in the bathroom and make sure it is always used.

Your indoor RH should be around 50%, when you get the meter. Much higher than than and you need to know why.

 

[foxhole]

Your 56% is not low it’s normal.


Both winter and summer levels fall within the 30-60% range, with a 10% variation at the appropriate end of the scale:

Optimal indoor summer humidity levels: 40-60%
Optimal indoor winter humidity levels: 30-50%

 

[Harry Bloomfield]

Below is my humidity log for the past 24 hours, which is typical and what you would expect of a home with no issues. Blue is the outdoors, green the indoor level.

You will notice the green indoor humidity begins to rise at around 11pm. That is because at around 11pm in this heat, I opened the windows wide on the upper floor, to vent the heat build up in the house during the day. You can also see a small rise at around 3pm, when I took a shower to cool down.

The blue outdoor humidity reaches a minimum in the heat of yesterday's afternoon, then gradually increases as the evening cools to a maximum by 9am. I have the system set to accept anything greater than 90% RH, to show 100%.

 

[doesitmatter]

Improve air circulation in house.
We install whole house ventilation units . Cheap enough , easy to install in the loft , locating the vent on landing ceiling . We fit them in Landlords property’s, because tenants don’t look after the homes like they would if it was theirs.
So the unit cleans the air in house, they seem to do what they say they do...in keeping homes damp free, condensation free.

I assume these aren't MVHR units?

 

[JohnD]

my damp man

Did he sell you silicone injections?

Why?

 

[JohnD]

Its in one corner of my kitchen

Kitchen, eh?

Is this a room that contains taps, pipes, sinks, dishwashers and drains? All containing water?

Which of them is leaking?

 

[RandomGrinch]

I assume these aren't MVHR units?

I may be wrong, but it sounds more like one of these to me:

Vent-Axia Pure Air Home with Heater Positive Input Ventilation 240V

Order online at Screwfix.com. Designed to eradicate condensation and mould from the home. Reduces the risk of health issues by improving indoor air quality and quickly eradicating conditions that lead to mould growth and associated health issues such as asthma and itchy skin. Reduces humidity in...

www.screwfix.com

 

[doesitmatter]

Aye, that's what I thought and was tempted to get them myself but I keep reading how they can work but require ventilation so condensation can be 'pushed out', plus really need to take fresh air, not loft air, which when it's cold (when condensation is highest) isn't sensible so would require air to be pre-warmed....as in MVHR.

 

[RandomGrinch]

Aye, that's what I thought and was tempted to get them myself but I keep reading how they can work but require ventilation so condensation can be 'pushed out', plus really need to take fresh air, not loft air, which when it's cold (when condensation is highest) isn't sensible so would require air to be pre-warmed....as in MVHR.

Anecdotally, I've heard they work well.
The one in the link does have a very small built in heater, and you do need a well ventilated loft, so it is taking in fresh air.

But it does seem to be a little wasteful to be constantly pushing expensively heated air out of the rooms, without any form of heat recovery.
Although if it helps to maintain a healthy environment, while reducing building fabric repair costs, when you can't control the whims of some tennants, then it's probably worth it?