Positive Input Ventilation

I put a Nuaire Positive Vent in the top of the stairwell, it’s fantastic. The only downside is it does very slightly drop the temperature of the house slightly. My house has concrete floors and suffered from condensation, the Nuaire has been brilliant (run for about 5yrs now). They also make the house air feel cleaner and dryer.

Think I need to sort the trickle vents first in the rear rooms that get mould, otherwise I suspect the PIV will just move air from the hall into the other three rooms (one with a ducted cooker hood, one with a ducted ceiling extractor, and one with a wood burner and flue). When I think about it, the two problem rooms just don’t have any permanent ventilation!

The thing with the PPV is making sure your loft is a dry air space first. If there is any condensation or damp up there it won’t work.

Other than that go ahead and put one in asap. They made an amazing significant difference to our 3 bed stone 150 yr old within a week, no need for extra vents etc.

Re a drop in temp, we noticed it if you stood directly under it, but the drop in temp feel in the house is prob more a difference in feel due to the drop in humidity.

We bought one with an air warmer and never used the warmer bit once

How do you know the heater has never come on? We left ours set to the stock ’10 degrees’ setting but I am assuming the air temp has been much lower than that in the loft during the -5 or whatever. I don’t have any way of knowing how much it has been on for though.

Our house is a bit older at just over 200 years, average humidity was around 75% before fitting, and is 55-60 now. Only had it through this winter. The vinegar is coming out in spring to scrub all the problem spots and see if they come back. It seems to be working well despite the loft being quite wet – it’s really well ventilated but the house vents up the gaps by the walls so much that all the humid air condenses on the lower beams/back of the wooden boarding. I was hoping the Nuair would help with this by drying the house out a bit and pulling more fresh air through the vents. So it’s a negative input ventilation for the loft, and positive for the house.

We really need to re do the loft insulation but if you add anything over the main living space it makes the boards soaking, I’m assuming by keeping the loft space colder directly above.

Next stage is buy or rent a thermal camera and try to find out where the warm air is coming up.

I did buy a Vent Axia Lo-Carbon PoziDry Pro PIV with Heater before Christmas, to fit in our house. But then we sold the house before I could fit it 😂

So if anyone would like to buy a brand new PIV then hit me up. Based J29 of the M1, if anyone is interested.

We fitted one of these some years ago and it made a huge difference to damp in the house and made the house feel warmer. It had to come out when we had a loft conversion (which seems to have been equally helpful for damp etc). That was in a ’30s semi with cavity wall insulation, double glazing and no trickle vents.