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Advice on positive input ventilation system


herby
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Hi all

 

A friends house smells of damp mold and is a cold house with only a multi fuel stove in the lounge, has heating on in other rooms but not all the time as out a lot. Have a company round as thought is was rising damp or other damp issue. The expert came out and suggested a positive input ventilation system for £2000 would sort the problem. Any thoughts welcome as I am not convinced.

 

Thanks

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PIV will help - but £2K seems a bit steep.

 

It consists of an input fan in the loft to a single terminal at the centre of the upstairs landing.

 

The fan is left on 24/365 and provides a low level input.

 

Nu Aire do a fan unit specifically at about £250 and a read of their web site will fill in the details. Good for 5 years before filter needs changing.

Edited by Yellow Bear
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We have one-- it's a version of I think 'envirovent' or a similar name.

It's in the attic space and has a single 200mm diameter hose to a vent through the ceiling.

Output is 'warmed' in extreme cold and has the capability of different volumes.

Since using this and placing additional airbricks in we have not had a problem since ( houses here don't even have DPM's).

We use a de-humidifier in the annex.

 

Air extraction units here in our region are popular due to the climate and if like my friends house- built directly onto rocks, one room has it impinging into the room.

They have no issues either since their install.

 

Hope this helps?

Think YellowBear was posting at the same time as it sounds like the unit we have...

def less than £500

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Thanks for the advice. I forgot to mention it is a ground floor flat with a bedroom at the back, kitchen then hall and toilet together. A lounge and bedroom at the front but these are fine. The problem seems to be the toilet, kitchen and rear bedroom. Flat roof over kitchen and rear bedroom the rest of the flat has another above.

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Thanks for the advice. I forgot to mention it is a ground floor flat with a bedroom at the back, kitchen then hall and toilet together. A lounge and bedroom at the front but these are fine. The problem seems to be the toilet, kitchen and rear bedroom. Flat roof over kitchen and rear bedroom the rest of the flat has another above.

They do one specifically for flats - again look at the Nu Aire PIV website.

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As yellow bear says above, I would strongly recommend nu Aire. I had exactly the same problem, got one of those nu Aire jobs for about 300. Its the model with a heating element built in. Cost 40 quid for an electrician to fit. It stopped the condensation and mould everywhere overnight. Bloody amazing bit of kit.

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Not sure of the actual age but its old, not listed but fairly old, guessing probably early 1900s, its stone construction at the front of the house but the rear is an added extension with a flat roof and is probably about 1970s build made of brick. the damp is worse in the newer part of the building. Not sure if it has a cavity wall. some of the windows are double glazed but not all. The rooms are currently heated with electric central heating and log burner in lounge.

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A PIVS would possibly help but in my experience some times they do sometimes they don't , it depends on many factors and they work most efficiently in modern well insulated properties which surprisingly don't need any form of active ventilation ! .

 

I wouldn't shell out for a Flatmaster system just yet especially if there are no obvious signs of bad condensation. Presumably there are wall mounted extractors in wetrooms, kitchens and bathrooms where this problem is eminating from. ? Are these working OK if not I would be tempted to replace them with humidity controlled units. Kitchens particularly produce significant volumes of moisture saturated air which tends to migrate to cold surfaces.

 

Check also if there are any airbricks in the existing wall which have been covered over, if these rooms are not heated then its will do no harm to uncover them. Also check if the windows have a night vent facility either in the head or in the hinge mechanism.

 

If the Flatmaster route is chosen £ 2k is about the going rate to be honest particularly as they will probably have to punch a hole in the roof finish and deck in each of the affected rooms in order for it to be effective.

 

A small energy efficient dehumidifier might be the better option.

 

Hope they get it sorted.

 

By the way is the flat owned or rented ?

Edited by Adge Cutler
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Owned. What do you mean by deck each of the rooms?

The rear extension having a Flat roof will have to have an externally mounted system ( Flatmaster ) the ducts will have to be punched through the flat roof finish and the deck and ceiling underneath it.

 

Each aperture will need an external weather tight collar and an internal grille. Then you have to consider a weather proof electrical supply to the ventilation unit .

 

Cheers.

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The rear extension having a Flat roof will have to have an externally mounted system ( Flatmaster ) the ducts will have to be punched through the flat roof finish and the deck and ceiling underneath it.

 

Each aperture will need an external weather tight collar and an internal grille. Then you have to consider a weather proof electrical supply to the ventilation unit .

 

Cheers.

Incorrect --Flatmate requires only one outside intake and this can be wall mounted - in fact this is recommended.

 

As an aside for Adge, over 60% of water vapour within most modern dwelling is as a result of the occupants IIRC about 1 litre a day - this cannot be lost through natural vent in a correctly sealed building particularly if trickle vents are either not fitted or open.

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Incorrect --Flatmate requires only one outside intake and this can be wall mounted - in fact this is recommended.

 

As an aside for Adge, over 60% of water vapour within most modern dwelling is as a result of the occupants IIRC about 1 litre a day - this cannot be lost through natural vent in a correctly sealed building particularly if trickle vents are either not fitted or open.

Apologies I stand corrected ... yes you are quite right I'm mistaking the nuaire input system for the Glidevale passive stack system.

 

Correct again ...but in this case the building is seemingly unoccupied for most of the day.

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