Has anyone fitted a PIV unit?

There has been a few threads on here in the past. Pretty much all positive experiences iirc (pun intended). I put one in a couple of years ago. It's certainly helped reduce damp.

I fitted one in my last place, it worked OK. However I recently bought a 20l Meac de-humidifier and found that to be far more effective. Both houses 100/100+ yrs old.

Yes. Fitted one about 8 yrs ago and forgot about it. Just runs and works.

I'm disappointed by this thread. The title led me to believe it would be a lot more raunchy.

easilyFree Member
I’m disappointed by this thread. The title led me to believe it would be a lot more raunchy

Sorry to disappoint 😂

Nick/Jam-bo This is the general feedback I've read. Works well, for and forget basically

Bill - we have a dehumidifier running but it will only target one area where as the PIV will hopefully do the whole house

Yes we fitted a Nuair eco dry a couple of years ago.

<br />We live in a 1700’s built listed  cottage & have to have single glazed sag windows. These used to be like niagra falls in the morning, with big pools of water on the window sills. Loads of black spot mold behind wardrobes & a feeling of general dampness around the house.

Before fitting the relative humidity was regularly up in the high eighties, whereas now it’s in the fifties. The air is dryer & the house feels warmer. My Asthma is much better & we no longer have any black spot mold in any bedroom.

<br />The way ours is fitted, due to the layout of the house & landing ceiling (alcoves & no clear ceiling run) it really shouldn’t work as well as it does, but it’s been great.

If I was to fit again I would definitely get the heated version as it can feel a little bit too cold at times. Also, I’ve had to change the filters after a couple of years instead of 5 because we live on a fairly busy road, which seems to contribute to more dust/pollution.

Yep fitted one myself a few years back. ( but there was a socket already in the loft)

contray to the above I bought a heated one. Even went to the trouble of putting in a remote control for the heating side of it. The temp difference was negligible and I never used it in the end

The only reason a de humidifier would be better is if your lost space isn’t suitable in the first place. ie it needs to be dry not damp and be fairly well ventilated 

My parent's bungalow has had one for over 40 years and it was the one thing that instantly and continuously cured condensation / mould problems. I've just fitted them a new one and the previous Nuaire lasted about 25 years. It was probably just the controller/ power supply that died, but with a set of filters it was cheaper just to fit a new one.

We also had one in our old bungalow for 20 years which worked equally well. I've been under / over every nook and cranny in both houses and can confirm that they aren't pushing the problem elsewhere e.g. floor joists etc. You are just promoting the gentle flow of fresh air.

Dehumidifiers are great for localised problems and drying clothes, but they are more expensive to run and don't fix the underlying problem of lack of airflow.

Following the various threads on here I fitted a Nuaire Drymaster Eco about 6 or 7 years ago (3 bed semi). It's been brilliant at controlling the condensation on the windows and keeping the mould at bay.

It has 6 settings, I've usually kept it on 3 or 4 (1 weakest, 6 highest) which keeps the humidity in the 60s, the only down-side has been a chilly landing.

Last winter I had the ancient double-glazing replaced, the fitter said nearly all my windows had been sat in pools of water! This seems to have been the main cause of the damp in the house, and with that now resolved the house stays in the 60s with the PIV on setting 1 - I'm even considering removing it.

In summary, in my experience they do what they do very well, but it's probably better identifying the cause of the damp and resolving it if possible. Having said that, I'm not sure how I'd have found the issue with my windows without actually removing them.

Fitted one in our 4 bed 70's built house.

It just works, only gripe is the cold air being brought in during the winter months.

To remedy this I added the heater unit recently, not really noticed much of a difference tbh.

Ours is a nuaire drimaster, anyone know what frequency we should be changing the filters?

This was the thread that convinced me to try one

https://singletrackmag.com/forum/topic/positive-pressure-ventilation-loft-units-which/

Some people seem to rate them but they can have issues as they push damp air out through cracks in buildings where moisture can build up as it hits the dew point. They don’t use the fundamental method of extracting damp air at source and supplying to habitable spaces. they are no longer accepted within building regulations and are not recommended under pas 2035 which is national guidance for retrofitting properties and is a requirement for any job getting eco funding. They are reliant on trickle vents in windows and door undercuts to allow free flow of air to all rooms which many properties do not have.

A few years ago I was swapping to a combi boiler & was ripping out the old pipework to the header tank in our walk in attic room & found that there was space to run a plastic extractor fan duct down to the ground floor, exiting behind the radiator in the hallway - does the same thing for less than £50

I've not bothered with a filter but that would be easy to do.

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Sorted out most of the problems in our c 1700 house within a couple of days.

There's a big thread on PistonHeads in the homes/diy forum which also has special offer prices if you troll back through the thread a good bit.

Also curious.

What are the running costs like? Are they noisy?

Also curious.

What are the running costs like? Are they noisy?

Eventually found a range of 1.6 - 17 watts (presumably depending on fan speed) for the unheated model, which works out at from 1p to a max of 12p a day on the current energy cap prices.

You can just about hear it when you're standing right under it, and the house is quiet. If you think about it and listen on purpose.