condensation issues-positive pressure ventilation

anselld

PPV system can only improve the situation if there is already some background ventilation in the rooms, e.g. trickle vents.

If the house is well sealed, double glazing, no vents, etc then it will make little difference unless the Ts also open the windows.

So the first step would be to ensure all rooms have some degree of trickle ventilation which is not dependent on the T ventilating manually.

Only once that is done and if the problem continues try the PPV.

kinger101

princeofpounds wrote: »

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 dryer, most moisture comes from normal and almost unavoidable daily activities; cooking food, having showers and breathing.

Window locks are available, and in any case, I wasn't implying that the property should be left insecure. Most of the condensation is created when the property is occupied. Either leaving the windows slightly open overnight, or if it's too cold, opening them first thing in the morning, will usually sort out humidity in the bedroom.

The bathroom should be fitted with a extractor fan to get rid to the humidity from taking a shower.

The kitchen should also have an extractor, and windows can be opened as well during and after cooking.

As for drying clothes, then a tumble drying (or even a dehumidifer) is a far better solution.

If all these simple fixes haven't been tried, then I can't really see the point in investing in a complicated solution. The problem with a positive pressure system as I see it, is that you can't guarantee that the air will circulate in such a way that it will solve the problem.....(unless you open the window ). As you pointed out, most humidity is created locally, and the solution (open window, extractor fan) also needs to be situated locally.

nod149

My home suffered with condensation for many years. I tried many many ways to reduce the problem. For the past 9 years there was only myself in the property and it still suffered with wet windows every morning in the cooler months. I have always opened windows, use extractor fans and dried washing outdoors - and used 2 dehumidifiers. Last December I had a PIV fitted and the problem was resolved almost immediately. The day after installation the windows were dry. Now after almost 1 year I would recommend the system.

ghandi

stator wrote: »

Or just buy a dehumidifier

I used to have two dehumidifiers running, a 14 litre and an 18 litre. They were using about 300 watts per hour each. The Drimaster 2000 uses about 15 watts per hour at full speed (it has 6 speeds) and the Drimaster 365 uses 24 watts per hour at full speed (it has 6 speeds).

So for me, a PIV system is cheaper to run.

anselld

ghandi wrote: »

I used to have two dehumidifiers running, a 14 litre and an 18 litre. They were using about 300 watts per hour each. The Drimaster 2000 uses about 15 watts per hour at full speed (it has 6 speeds) and the Drimaster 365 uses 24 watts per hour at full speed (it has 6 speeds).

So for me, a PIV system is cheaper to run.

Not a fair comparison as you are not counting the increased heat loss through improved ventilation in the latter case. Dehumidifiers dont have those losses as they are generally best used without ventilation.

PS there is no such thing as watts per hour, it is just watts.

ghandi

anselld wrote: »

PS there is no such thing as watts per hour, it is just watts.

There is but I 'misused' it to make it really easy for the laymen to compare (e.g. power plant ramp up). Otherwise we will end up comparing the different loads, types of power, PF, etc, etc and then it starts getting complicated

Leven

Does anyone suspect that cavity wall insulation could cause condensation/mould problems? I had cavity wall insulation installed into a hitherto 'healthy' end terraced house (been in the family many years).

Tenants were living in the property at the time of the installation and did dry a lot of washing indoors, take long showers (self confessed) and I can't prove they weren't opening windows. That year the house began to suffer from a mould problem, mainly in the living room (not on the cavity walls, but curiously on the leather suite and was starting to show on the bottom slats of wooden blinds) and their bedroom window was wet inside.

Unfortunately, I didn't find out about this problem until they left and I had a poke around.

I wondered if the cavity wall insulation caused or excaberated this mould manifestation. The next tenant didn't have a problem with it though. I'm not sure what is happening with the situation this year as new tenants are there and its not really been winter for very long.

Either way, I really wish that I hadn't had the cavity wall insulation installed. Cavity walls are cavities for a reason and I belatedly came to believe that a house needs to 'breathe', not be suffocated by whatever it is they stuff the cavity walls with.

camptownraces

I have PIV systems installed in two flats. (Envirovent)

Tenants do normal things like frequent showers, drying clothes indoors etc.

No mould. No windows open in winter either. No nagging from landlord.

Powerful extractor fans in kitchen and/or bathroom are also part of the set up in this case.

specialboy

We live in a 130 year old cottage that has been modernised over the year but probably not for the better, we suffered for years with moud and condensation until we have a vent axia system fitted and almost overnight the problem has vanished. Running costs are a fraction of a dehumidifier of which we previously had 3 running. Cost of the system is only £350 and you can easily fit it yourself