Positive input ventilation

[Conner]

The system I have been looking at is just the PIV. Supposedly works by having a slightly higher pressure in the house forcing out the stale are through gaps in the house. Designed for older houses.

The air from the loft can be heated but still looks to be cold. 
I was hoping someone would have used this in real life. 

[Treetom15]

Sorry if I’ve missed something, so the fan forces the old air in the house out through gaps, to stop damp buildup etc? I would imagine it would do a similar job to open windows at opposite ends of the house and create a thru draft?

We have been in our new house since mid November, which is a timber frame near passivhaus build, with an MVHR. That works well (so far!) in terms of recirculating air, and moving air from warm areas (bathrooms) to the rest of the house. Not sure if they work so well on older houses with less of an air seal. Do these PIV pumps “warm” any air coming into the house? 

[carlos]

1 hour ago, Conner said:

The system I have been looking at is just the PIV. Supposedly works by having a slightly higher pressure in the house forcing out the stale are through gaps in the house. Designed for older houses.

The air from the loft can be heated but still looks to be cold. 
I was hoping someone would have used this in real life. 

sorry i havent got any experience with these systems, plenty of info on the net else where though.

id say finding the reasons for the damp will help to work out the best solution, this is what iam kinda doing at the moment on our house.

hope you get a solution, let us know if the system helps if you do end up installing one.

carl

[GarethM]

PIV sounds like snake oil, turning a damp house into a colander and wasting money on heat.

 

To prove you concept reverse the flow on a bathroom extractor fan.

[difflock]

On 20/01/2023 at 16:42, Conner said:

Hi gents. Hoping I can get some feedback on a PIV system. Have been looking at installing on of these to try and reduce damp in the house. Online reviews look very good so would like some real world experience before shelling out.

Open a window, or two.

[coppice cutter]

7 minutes ago, difflock said:

Open a window, or two.

I was going to suggest that but was afraid I'd be accused of being crass.

 

So I'll just agree but let you take the flak.

[Squaredy]

On 20/01/2023 at 16:42, Conner said:

Hi gents. Hoping I can get some feedback on a PIV system. Have been looking at installing on of these to try and reduce damp in the house. Online reviews look very good so would like some real world experience before shelling out.

Like most of the other replies from other members I can't comment from personal experience.  BUT, all a PIV system is doing is providing ventilation.  This can be done well with windows.  The reason you don't want to simply leave multiple windows open in your house may be to do with security and heat loss.

 

So there is the problem, it may work well, but in cold weather you are losing all the heat from the air being pushed out of your house.  In extreme heat the opposite problem will occur. If like my house you have areas that stay cool as they never get the sun, these will get hot as you are pushing the cool air out.

 

Unless I have missed the point and it actually heats the incoming air.  In which case how does it do this?  If by electrical resistance heating that will be very expensive.

 

So using logic, it may well work, but at a high cost except when the temp outside is the same as the temp inside.  I am sure you could easily "prove" that it is an efficient system if you only measure the cost of running the PIV system and not measure the extra cost of heating the house.  Or measure the performance in warm weather!  Imagine running this system in the current UK weather conditions...

[Conner]

Yes all the above arguments have crossed my mind. Heat loss windows open etc. 

The problem we have is mold along the window wall in the bedrooms. Tried keeping windows open all year round no better.  Two extractors in bathroom still no better. 
A work mate mentioned PIV looked at how it works seams to make sense. Looked at all the reviews google Amazon etc all good but do you believe them. Thought I would ask the collective  as many knowledgable people on hear 

[trigger_andy]

5 minutes ago, Conner said:

Yes all the above arguments have crossed my mind. Heat loss windows open etc. 

The problem we have is mold along the window wall in the bedrooms. Tried keeping windows open all year round no better.  Two extractors in bathroom still no better. 
A work mate mentioned PIV looked at how it works seams to make sense. Looked at all the reviews google Amazon etc all good but do you believe them. Thought I would ask the collective  as many knowledgable people on hear 

Have you thought of pulling down the Plasterboard and investigating the issue properly? 

 

Are all the Bedroom walls aligned on the same wall? Potentially an issue outside? 

[Conner]

Both bedrooms on same wall west facing. I have had the roof checked by a trusted builder and nothing found all looks ok. Guttering ok. I have removed coving and nothing under it. Seams to be condensation on a cold spot on the ceiling. Insulation done to current standards and looks to be right up to wall. This afternoons job is to pull insulation back check top of plaster board.