Condensation/Mould Solutions - PIV

McKnze21

Hi

I am wondering if anyone has any advice on PIVs, Positive Ventilation Units?

I have an issue with condensation appearing on windows, mainly to north side of the house. Along with black mould forming in the lower external corners of the north east and north west corners of the rooms of my detached bungalow. 

Without having heating on quite a bit and/or opening windows, how can I resolve this? Would a PIV system help? 

I do not currently have any extraction units fitted in my bathroom or en-suite but I do plan to have these fitted also as I know this won’t be helping either. 

Thanks!

Ms_Chocaholic

As I understand it the air has more difficulty in circulating in bungalows, presumably due to no stairs.  You need to install those extraction units in bathroom and en suite urgently, open the windows to ventilate and buy yourself a dehumidifier.  Get yourself a humidity monitor in the meantime before you buy the dehumidifier and you will probably see that your humidity is quite high as there's no way for the steam from the bath/shower and even vapour from breathing to leave the property currently.  

Personally I wouldn't bother with a PIV, they're expensive to buy and service and even parts like a new filter cost the earth.  You can achieve the same doing the above and keeping an eye on your humidity levels.  We've got a Meaco Dehumidifier and when you switch it on the display shows the humidity level.  They're great, it cost £180 from John Lewis about 18 months ago.  This is the one we bought, it's on wheels so easy to move from room to room as needed, it even has a setting to dry clothes and save ££ using tumble dryer.  The reviews speak for themselves https://www.johnlewis.com/meaco-arete-one-dehumidifier-air-purifier-12l/p6218144

Read this, this will help

https://yorkshire-condensation-control.com/the-problem-with-bungalows

tacpot12

A PIV system is likely to help, but I can't guarantee it. The problem with the mould in the corners might not be cured by a PIV system unless you can find a way to move some air into the corners or heat these rooms at little better. 

An alternative would be a dehumidifier. These tend to be cheaper than PIV systems, but they aren't something I have any experience of. Hopefully someone that does will be along to offer more advice. 

I am a fan of extrator fans that are controlled by remote humidistats so that if the room is damp, they run until the room is dry, but if you fit a PIV you probably won't need to extractor fans in the bathroom and kitchen.

Having extractor fans running a lot might seem expensive, but these days there are very efficient fans available that are also very quiet.  

WIAWSNB

McKnze21 said:

Hi

I am wondering if anyone has any advice on PIVs, Positive Ventilation Units?

I have an issue with condensation appearing on windows, mainly to north side of the house. Along with black mould forming in the lower external corners of the north east and north west corners of the rooms of my detached bungalow. 

Without having heating on quite a bit and/or opening windows, how can I resolve this? Would a PIV system help? 

I do not currently have any extraction units fitted in my bathroom or en-suite but I do plan to have these fitted also as I know this won’t be helping either. 

Thanks!

Hi McKnze.
Which room is that? 

McKnze21

That is in a bedroom. The bedroom on the North West Corner. Window is on North face of house and that corner is the lower internal Side of the North West. 

As for PIV, I considers this as I wanted something for multiple rooms and as PIV is whole house I thought possibly better than purchasing multiple dehumidifier’s?

WIAWSNB

Whose bedroom?

Does it need to be kept at a certain - highish - temp for any reason?

Ok, assuming not, this is something to try;

1) As soon as the bedroom is left unoccupied in t'morning, open all the window openers to at least its 'vent' setting, or a good inch or two if you can, if security isn't an issue. 

2) Turn the heating - CH radiator - off in that room - ie, down to, say, 1 or 2 tops. You don't want it coming on at all during the day, and only weakly overnight if it's really bludy freezing.

3) Shut the internal door to the bedroom, and walk away. 

4) Try and keep that damp corner as open as possible, with nothing sitting close to it - let air circulate.

5) Clean and kill that mould with mould killer/bleach.

6) Before bedtime, close the windows to 'vent', but leave them like this all night. Do NOT shut them fully. DON'T!

7) If you wish, by all means have the heating come on for a half-hour or so before bedtime just to make the room more welcoming. A cheap and easy way to do this is to use an oil-filled radiator on a digital timer - rad on Fb for £15, and digi timer £10 on eBay. That way you don't even have to think about it. Oh, and set it to come on a half hour before wake up too. This will cost pennies, and is the only time you need heat in that room.

8) Keep warm using a good duvet and an electric blanket - also set to come on with a timer. If you are a complete wuss, you can buy an all-nighter.

9) No need to be chilly in your bedroom, but don't do so by shutting the windows and turning up the CH. 

10) Do the above. Your condie issues will disappear. I'd even site the oil-filled close to that corner as that is clearly the coldest spot in the room, apart from the windows, obvs.

You are very welcome

Separately, fit a good quality extractor fan in the bathroom as Tacpot suggests. My bro just had new extractors fitted in his loos, and they were silly money - around £150 each? But, they are fully controllable (I think by BT and phone App), run pretty much constantly at next-to-no power consumption, are literally silent unless working in anger, and are humidity controlled. Oh, yes, and react - it's true - to odours. 

The installation of an extractor will be the biggest part of the cost, so it's worth forking out for a model that you can then ignore, but which will keep your rooms ventilated as needed. (I'll try and remember the model). 

Any room in the house you are not actually using, then ditto - crack the windows to 'vent' 24 hours, rad down to '1', and close the door. You will have cooold rooms, but they will be dry.

bjorn_toby_wilde

Start by looking at where the moisture is coming from.

1. Your bathroom and en suite definitely need extractors. Take a look at the Airflow Icon. It has a clever design like the shutter on a camera which closes when the fan turns off and stops a cold backdraft coming through the vent in winter. We have one of these and it’s great. They do different modules; a timer, humidistat etc.  Not cheap but very good.

2. Kitchen - does your extractor hood remove air to outside? If not then that’s a big source of moisture. Consider ducting that to the outside. Do you have a condensing tumble drier? Some of them are really poor at the condensing part and will leave much of the moisture in the vented air.

When you’ve addressed those issues you’ll have a better idea of whether you need PIR I think.

Rummer65

We had similar problems in a 2 bedroom bungalow, black mould in the hallway and 1 bedroom after trying dehumidifying units we installed a PIV about 3 years ago and have never looked back

noitsnotme

I’m not in a bungalow, but fitted a PIV 3 years ago and it massively reduced the condensation problem we had.  On cold days the windows were like rivers with pooling water on the window sills.  Now we get a little bit of misting up at the very worst on the very coldest days.

It was more expensive to buy than a single dehumidifier, but as noted above, it only needed one for the whole house.  And I don’t need to constantly empty it.  I believe that a PIV unit uses less electricity to run too, certainly less than multiple dehumidifiers.  I fitted it myself which isn’t difficult if you’re handy at DIY.

The biggest downside to the PIV is that the landing directly below the fan is always cold.  But as a family we all agree this a small price to pay for the improvements it has delivered.  No one hangs around on the landing anyway, it’s just a place you’re briefly moving through between rooms.

I don't know how well they work in bungalows, but for our house it has certainly been a very good addition.

Bigphil1474

We had a condensation and mould issue in our bedroom when we first moved in. We manage it by leaving the window in the vent position all day, close it at night, then re-open on a morning (in the winter). Leave it open all the time when it's warmer. The heating comes on for an hour before bed time and again in the morning. No more condensation. Mould was cleaned off and hasn't come back. Ours is upstairs though.

We don't have extraction in the bathroom, we just leave one of the windows open to dehumidify.

noitsnotme

Ms_Chocaholic said:

Personally I wouldn't bother with a PIV, they're expensive to buy and service and even parts like a new filter cost the earth.  

£40 a pair for the filters for my PIV, not quite the earth.  I’ve not needed a new set in 3 years so far.

The unit itself was £450 but with hindsight I could have saved around £75-£100.  The one I bought is supposed to heat the air entering the house but it doesn’t work very well so I don’t have the heater switched on.  The same PIV without the heater would have been adequate at the cheaper price.  No fitting cost as I did it myself, although someone without the ability to do that would need to factor in those additional costs.

I did consider dehumidifiers initially but while researching, discovered PIVs and figured they could work out cheaper in the long run.  To cover the whole house, you would need 3, 4 or maybe more dehumidifiers.  So at £180 each in your example, it’s starting to cost more than a single PIV.  A single PIV supposedly uses less energy than a single dehumidifier.