Positive input ventilation system for the home - anyone got one?

1840s house, 1880s extension, solid walls, had problems with condensation and a little mould. We had a PIV fitted in the loft with feeds into 2 of the upstairs bedrooms. Also added 4 vent tiles to the roof and a good fan to the bathroom around the same time. Already had an air brick and cooker extractor hood in the kitchen room plus the house is generally 'leaky'. No problems with condensation since, very happy with it. This was done about 10 years ago. The PIV was £1000 fitted, fan was a couple of hundred. All done by Envirovent ( https://www.envirovent.com/ ).

Not currently got one in our new house, but I fitted one in our last  house. It removed black mould within days, air quality improved, condensation massively reduced

They are very very simple to fit if it’s a loft one. I just cut the hole in the ceiling and suspended the unit from joists. 

I got a sparky to wire it up.

Is it a ‘normal’ installation ? ie going in a dry loft space?

It really is a simple DIY job

Ours just vents into the central area. Loft was already well ventilated. 1860s stone building. Was very damp, now is pretty good. Far less condensation. I also fixed a couple leaks in the room at the same time so can't say it's all the PIV but I'm convinced it makes a big difference. Was £300 or so to buy, DIY installation.

Do you need all those vents? How well sealed is your house? Personally I'd just whack one in above the stairs. If it helps great, if you still have some damp spots then maybe improve ventilation in those areas. Decent extractors, especially in a shower room are a good idea. If you already have one then putting a bigger fan in is relatively straightforward 

There's a few threads on here about them. 

Fitted one about 8 years ago (1920s semi) difference was noticeable almost straight away. 

A couple of years ago we had the double glazing replaced and the installers said the old windows were all sat in puddles which were probably causing the damp problems. Since then the ppv is set on the lowest setting, it still helps but is nowhere near as essential as before.. 

Also, I fitted it myself, very straightforward, it just vents onto the landing 

I fitted one on a landing in a terraced house many years ago. Cost around £500 with a remote. Not been round to the house it is in for several years so I can't comment on how well it performs but it could certainly push a decent amount of air through the windowless landing and probably helped. Nuaire drimaster if my memory serves me correctly. 🤔

Early 1700's stone house here. Fitted a Drimaster ourselves, 2 days later no more condensation on the windows, and bleaching the mold is maybe a little once every 6 months instead of lots every 6 weeks.

An old house is likely to be plenty leaky without fitting air bricks etc; if you did find anywhere is not improving after fitting the fan, you can always look at that sort of thing then. 

There's a long thread on PistonHeads in the "homes, gardens & DIY" with reduced pricing offers (someone who works for Nuaire is on the forum) if you work backwards through the thread a bit.

£4500 is pulling your pants down to let you feel the breeze! (Although you could/should also look at extraction in the kitchen/bathroom if you don't have any at the moment)

I don't have condensation problems but some rooms do get some mildew and mould. 60s bungalow.

I was going to fit one but delayed it as I was reading that it can push damp warm air into voids etc and move the problem where it can't be seen. I also decided I should do the basics first, fit trickle vents to the windows and trim the bottom from the internal doors as they were not allowing the required ventilation between rooms. I'm also concerned that most of the airflow would go from hall, straight into living room and up the stove flue or out the cooker hood, leaving the problematic rooms at the back of the house with stale air.

Nuaire Drimaster - Absolutely brilliant, eliminated mould and makes the house much fresher. I don't use the heating element and don't think it's needed.

another happy Nuaire user. fitted it about ten years ago and not really looked at it since. £4500 quote seems punchy.

RH current sitting at 49% in an 1880's solid wall terrace that are notorious for damp problems. 

Thanks for the replies, it all seems pretty positive and a way forward. I'm going to get some one in to install it as to say i'm cack handed at diy is an understatement and I wouldn't trust anything electrical that I have touched. 

The bathroom definitely needs some form of extraction, probably the kitchen too but I have some reservations of the extractor getting all gummed up with grease from cooking, is that likely to be a thing?

And yes, airbricks, thinking about it do we really need one in the lounge? We have a chimney for an open fire that isn't sealed as we use it so surely that is more than enough. The rest of the house is actually pretty well sealed as we had new doors and windows installed when we moved in 7 years a go.

Off to get some more quotes, if anyone knows a reputable installer in Sussex please let me know.

1950s corporation build. 

never been an issue till we tightened the building envelope and fitted new windows. 

all our ventilation from the eaves is now contained in the attic space instead of blowing around the house. 

this lead to dormer cheeks (which are poorly insulated) getting moisture and mould on. 

the PIV replaces that with a controled amount of air and has eliminated the mould. 

ours a Vent axia in the attic - feeding into above the downstairs landing. I bought the heating model - after 1 winter i turned the heating down to come on only if attic air is -10 and for the large part it was 500w of waste - the air coming out is never warm. 

Make sure the unit is hung from the rafters rather than screwed down on the legs ..... if you screw it down you will hear it . 

i self fitted - it was 330 quid for the unit and another 20 for a large holesaw. took a couple of hours to fit - stuck it on a smart switch so i can turn it off for summer without crawling around the attic and also monitor its power draw. 

Number of things

You really need extraction in the bathroom. If you have an extractor above the cooker I wouldn’t worry too much about.

As to air bricks, you are in theory supposed to have one in the lounge if you have an open fire. I would get a chimney sheep, it will save you money when your fire is not in use. Oh and a carbon monoxide alarm for the lounge if you haven’t got one already 

Had one fitted by Envirovent in Brighton for £600 over 15 years ago. Huge transformation. All black mould and condensation gone. Moved house and self fitted a nuaire in the next house which also solved almost all mould and wet walls in poorly insulated chalet style bedrooms. 

I have the experience of buying one. Was going to fit it but we moved house in the end. So if anyone fancies one of these cheap, then let me know, as it's sitting in a box in my garage taking up space.

https://www.vent-axia.com/range/lo-carbon-pozidry-pro-heater