condensation issues-positive pressure ventilation

marc3

I write as a landlord, with a minor condensation issue with a tenant (usual stuff )

Equally-we do like to maintain/constantly improve our properties..
been doing a bit of preliminary reading on this positive pressure ventilation system,

theory reads great-but do they work in practice ?

because of nature of buildingours would have to be hall as opposed to loft installed.

Has anyone any experience of these PPV units and do they work/worth the money ?

kinger101

I know what works great. Opening the windows. Make sure they're not drying clothes on radiators as well.

dirty_magic

kinger101 wrote: »

I know what works great. Opening the windows. Make sure they're not drying clothes on radiators as well.

Everyone says this but if there's a serious lack of ventilation in the house it has little effect. Our flat has condensation and it's a nuisance in winter.

We have our bathroom window open almost constantly (no extractor fan), the kitchen window is open during and after cooking and other windows are open as often as we can without getting too cold. We bought a dehumidifier to dry washing as it's not practical to say don't dry washing indoors in winter; most of our clothes can't be tumble dried.

The Windows are still wet every morning in winter and our furniture and walls still keep going mouldy, as do the tiles in the bathroom.

I think the landlord is right to consider other options, it will make his life easier with both current and future tenants.

Hanky_Panky

I often wonder what those newer properties are like with no heating but are effectively sealed - I think they even wrap them and pressure test them. With no/minimal air coming in how do they stop condensation ?

princeofpounds

With no/minimal air coming in how do they stop condensation ?

They do have air coming in. They are mechanically ventilated, but the point is that the air exiting passes through heat exchangers with the air entering, so the energy is saved.

Personally, I think they are a pretty stupid idea because maintaining the seal over decades will be near-impossible and I also dislike relying on powered ventilation alone. They are efficient though!

I've not had experience of PPV systems but I suspect that they are not that different to regular ventilation in terms of the effect they have on damp.

PS I really dislike the sarky comments that you always get talking about condensation damp

- just open the windows; yes, it works well, but is not always possible for security or noise reasons.
- stop drying clothes in the house; yes, it's not good practice - stupid even, but plenty of flats don't have outdoor spaces and even when you do, it sometimes rains.

The fact is that apart from things like clothes drying, most moisture comes from normal and almost unavoidable daily activities; cooking food, having showers and breathing.

Any property that is not able to deal with these things ultimately has some kind of design fault. And we have a lot of badly designed and built properties in the UK when it comes to damp management.

ghandi

I have been using a Nuaire drimaster 2000 (loft mounted) for a few years due to condensation problems.

I had vented soffits fitted and also have a couple of ridge vents as well so the loft gets air from outside circulating through it; I did have condensation in the loft as well but this has now gone after have the vented soffits fitted. I don't have any extractor fans fitted, all the windows have trickle vents. I have gas central heating with radiators and every radiator has a TRV.

The drimaster (vents on to landing) has worked really well and instead of seeing streaming windows in the mornings, the windows are clear or I sometimes get a little bit of condensation when it's been really cold overnight; it soon clears though. The days of black mould on walls are gone, although I do sometimes get the odd little patch of black mould on my shower curtains; I really should fit a bathroom extractor (adds to list).

The house also seems fresher and when I have turned the drimaster off for a few days I noticed how much my house 'smells'; LOL.

I have just removed the Drimaster 2000 and fitted a Drimaster 365 which can take air from a soffit/wall vent grill instead of from the loft dependant on temperatures; I wanted this feature to drag cold air into the house on summer nights when the loft air is still warm and the outside air is cooling.

For me, PIV was ideal to deal with my condensation problems. My next door neighbours (we're terraced) still suffer with bad condensation/ mouldy walls and the only difference is they don't have PIV; their bathroom window is wide open all day no matter what time of year.

The moist air in the property needs to be 'pushed' out of the property by the cooler less humid air being 'pumped' in by the PIV; so it will need ways of getting out of the property e.g. trickle vents.

stator

Or just buy a dehumidifier

booksurr

ghandi wrote: »

I have been using a Nuaire drimaster 2000 (loft mounted) for a few years due to condensation problems.

interesting

presumably the system only works if you have bad seals around interior doors otherwise how does the air being pumped into the hallway affect the other rooms in the property?

I notice that heating the dry air being pumped in is an optional extra. Therefore do you notice cold draughts around the doors - having spent a lot of time on installing draught proofing around doors I'm interested in how the system would work if there is no through flow inside the house?

theartfullodger

I took back 2 properties this year, each with reported damp/mould/condensation problems: Provided dehumidifiers, dropped rent, strenuously encouraged ventilation & heatings: problems remained. Tenants departed. Evil landlord then ensured effective ventilation & heating: In both cases problem gone after 2 weeks, albeit re-mould sprays and/or redecoration required.

No complaints from either set of new tenants...

jjlandlord

Drying clothes indoor may be unavoidable. Either:
- Use a tumble dryer,
- Or dry them near radiators but also close the door of the room and have a dehumidifier run at the same time: Heat transfers the water from the clothes to the air, and the dehumidifier transfers it from the air to a bucket for disposal.

Re. opening the windows, especially in bathrooms and overnight in winter, one must keep physics in mind and a key aspect of it, the dew point:

You take a shower while, presumably the room is warm. So the air can contain a lot of water (dew point is high).
Then you open the window while it's cold and likely humid outside: It causes the bathroom's temperature to drop, lowering the dew point, causing rapid condensation, which won't go away (in the morning there's often dew everywhere outside: the outside air is already saturated).

To avoid condensation, first keep the moisture in the air, then take the moisture away.
In a bathroom you need a fan to ventilate the room while keeping it warm, and/or a dehumidifier.

marc3

thankyou ghandi for specifically answering the question;and indeed would welcome other responses from anyone with experience of ppv systems.

with regards to the general condensation replies-thank you as well, and like most-i do have a just little bit of experience of damp/condensation issues.

Its the new stuff-ppv systems -where i have no experience that i am looking for feedbck on.