PIV system

mrochester

mrochester

mrochester

Soldato
Joined
29 Sep 2003
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Location
Newcastle upon Tyne
Hello.

Im currently staying in a cottage that has a heat exchange system in the loft space with ventilation in every room. It’s really noticeable how ‘fresh’ the air feels around the house and how there is no condensation anywhere, but it’s also still warm.

I have terrible condensation on my windows at home to the extant that mould grows, and they are older double glazing units so don’t have trickle vents. Short of having the windows open all the time, which isn't practical for heating and noise reasons, im interested in other solutions.

I had no idea that these home ventilation systems even existed but apparently you can get something called a PIV that blows filtered fresh air from your loft into your home. Does anyone have any experience of these and how effective they are? It looks like the systems I’m looking at simply vent into the home in one location (say your landing). Would that be enough to ventilate an entire 3 bed semi or do you really need a system with ducting to every room (at which point replacing the windows might end up being cheaper!)?

Many thanks.

M.
 
Going off of what I’ve read so take with a pinch of salt.

The PIV systems do as you say. And they do tend to resolve a lot of condensation issues. They create positive pressure and push all the moist air out of the nooks and crannies in your house. And having just one inlet is usually enough. However you will lose heat with one of those.

The heat recovery systems are more expensive and harder to install and I believe need inlet vents in every room (could be wrong). I think they only work in effectively in a very well insulated home.
 
I had a heat recovery system in a house once, it was also a noisy bugger.

A good system that does this without generating a lot of noise sounds good, sadly not my experience and I'd have preferred trickle vents.
 
HungryHippos said:
I had a heat recovery system in a house once, it was also a noisy bugger.

A good system that does this without generating a lot of noise sounds good, sadly not my experience and I'd have preferred trickle vents.
Click to expand...

That's manufacturer dependent. There are very quiet systems available.

Mason- said:
Going off of what I’ve read so take with a pinch of salt.

The PIV systems do as you say. And they do tend to resolve a lot of condensation issues. They create positive pressure and push all the moist air out of the nooks and crannies in your house. And having just one inlet is usually enough. However you will lose heat with one of those.

The heat recovery systems are more expensive and harder to install and I believe need inlet vents in every room (could be wrong). I think they only work in effectively in a very well insulated home.
Click to expand...

I don't think you'd need them in every room, but I don't understand why you would need vents in every room if PIV doesn't require it. Positive pressure will push air and heat out, so I'm not sure why a heat exchanger would resolve that. You want to extract air from your house (negative pressure, suck moisture out of cracks), recover the heat from that and put it into the supply air pathway.
 
dirtychinchilla said:
That's manufacturer dependent. There are very quiet systems available.



I don't think you'd need them in every room, but I don't understand why you would need vents in every room if PIV doesn't require it. Positive pressure will push air and heat out, so I'm not sure why a heat exchanger would resolve that. You want to extract air from your house (negative pressure, suck moisture out of cracks), recover the heat from that and put it into the supply air pathway.
Click to expand...
Yeah heat recovery systems aren’t the same as PIV. Don’t think I said they were. The every room thing is just what I’ve seen. Don’t know if you can get away with having less vents with them.
 
thread where we discussed them last year

Positive Input Ventilation opinions please?

If all vents and windows are shut, where is the air going to? Into the loft I expect. You're not going to remove any moisture if the air has nowhere to go. I think you are over estimating the air tightness of a 90s house. Just window vents are closed, not extractor fans etc
forums.overclockers.co.uk forums.overclockers.co.uk
 
I've had a nuaire piv before, they're fine.. But in your case just drill a couple holes and add trickle vents to your windows.
 
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