Posted 23 January 2023
Positive Input Ventilation unit
Anyone here got this? I'm looking at getting it put in for a condensation issue causing mould. I already have a dehumidifier and open the windows. i only really want it for one room but happy to have thru the house. Does it make the house cold? Any feedback would be appreciated?
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sorted byI think the unit above is different from my nuaire. But the fitting is the same by the looks of it (edited)
small sacrifice for a much more comfortable living environment (edited)
Most units have a heater that warms the air when temp falls below a set level.
We have a small MHRV unit in a bathroom and a PIV in our bedroom. Both do a good job but the PIV isnt as good as the mhrv.
It's early days but but currently very pleased with it.
I was concerned about where cold air being pushed in would make the house feel cold - and I can honestly say it has not made any difference in this respect. You do however still need to ensure the house is warm - at least 16 degrees - otherwise there may be a recurrence of problems and many (not all) mould/condensation issues are due to the property being too cold all the time.
One huge improvement we have both noticed, almost from the first night was how much cleaner and fresher feeling the air is indoors. We have never noticed it to be awful anyway but because the PIV is filtering the air it's pushing in, there is a very noticeable improvement - like standing on a mountainside breathing in pure air! Lovely! (I assume this as I have never stood on a mountain!)
So far so good. Only time will now tell. (edited)
If it's one room then is the window in it facing the prevailing wind or sheltered from it? Try opening just that window and a window elsewhere in the house where the opposite is true (and the doors between them of course).
I'd have thought the primarily advantage of having the air blown in by a fan is that it gives you more options for airflow paths in case you don't have vents in the right place.
but loft is converted to a bedroom?
don’t want the house even colder!!!
Your loft conversion may be an issue though (edited)
Its a pitched roof above the extension but no way of accessing the inside so a PIV is not gonna be possible.
To make matters worse there is not enough wall space on the outside wall in the extension to fit any sort of extractor fan.
Currently I’m running a dehumidifier which has dried it all out nicely but I was hoping for a long term solution.
Further bonus is we no longer need to open windows for fresh air thus losing our heat. We still open the bathroom window after the shower has been on to let steam out however. But it has been odd getting used to not opening other windows and also leaving doors open thru the house.
The original issue with mould seems to be resolved. I’m not sure how long to wait till I can be certain of that. We sprayed the affected area before the PIV was installed and scrubbed it out taking the paint with it. We’ve repainted with mould resistant paint so that’s a bit of wait and see now. I’m optimistic it’s resolved because of how well the PIV is doing.
Next job is to sell the dehumidifier. (edited)
Currently I have meaco dry arete one 20 litre but I only put it on every other night for at least 8 hrs. It cost about £0.70 every other night. And it has worked magic. But I like you feeling fresh air like been on mountain.
Thanks please update us you go.
I can't say at the moment about running costs but that was something I was very conscious of. I was running a Meaco Dry 12L at 0.05 per hour - and on very cold days and nights it was on almost all the time.
When the PIV surveyor came out I asked about running costs and it is meant to be very low cost - having said that some things can alter how much that it is.
Our PIV has it's own 'comfort' heater - this switches in automatically if temperatures in the loft are very slow to stop cold air being pushed into the house - it does not heat it by much but just enough to stop there being a cold draught. In warmer months the unit will switch the heater bit off. So when the heater is in use there will be some higher running cost but not a huge amount.
From the Specs -
Annual Running CostsAt speed 1 and 2 the unit will cost less than £6.00 a year to run. Annual running costs are calculated with the comfort heater disabled (All costs are based on an electricity cost of £0.15 per unit (kWh)).
I have lots of other blurb but don't think I can post it here due to copyright or advertising or falling foul of something else. Happy to be contacted for more info if you are looking at getting PIV.
Another bonus with the PIV is the lack of noise. Especially at night. Our PIV is effectively fit and forget - after 5 years the filter will need to be changed. The unit has a 10 year warranty.