Still getting condensation three weeks after PIV installed

markin

The window looks very old,  early 90's with trims on the outside, so probably not great gas in them.

A dehumidifier on the landing may be far better use of electric.

Chloe_G

I had a blackout blind in my bedroom window recess for years and my window was like that most days in winter.  Since I took it down and just have curtains with airflow around I just have a couple of inches of condensation at the base on cold days.

Doubleshotdamo

Freezing cold house this morning with this thing set on number 4. Condensation again! I'm not putting it above setting 4, as my heating is constantly coming on, it's going to cost me a fortune. 
I guess I'll put this down to bad luck, or bad windows, I don't know. I'll see if I can return it as it's not fit for purpose. 

Ben1989

This isn't normal. 

Check your ducting seals or you might have a dodgy unit.

One day just run your unit at power 6 then you know for sure you have an issue!

rob7475

Do you have good ventilation in your loft (can you see daylight at all through the eaves etc?). If the loft is struggling to draw in fresh air, the unit won't be able to do it's job properly

ComicGeek

Both heat and ventilation are needed to combat condensation. You need to bring in sufficient cold dry air and then heat it, so that it can pick up water vapour - you then need to get rid of that warm moist air, replace with dry air and repeat. If it's just condensation on windows, which can be wiped down in the morning, why bother spending lots of money trying to change that? 

Condensation on bedroom windows with heating off and people sleeping = normal.
Condensation on other room windows = not normal, and would normally mean ventilation/heating issues.

We keep our bedrooms cool to help with sleeping, and don't have the heating on overnight - normally drop from 17 degrees in the evening to 14 degrees in the morning, with night time temperatures of -5 around here at the moment. Condensation on the windows is guaranteed at the moment with sub-zero outside temps, but quick wipe down in the morning in the bedrooms and all good. Our house is now at 19.5 degrees downstairs (bedrooms at 17 degrees), bedrooms, bathroom and ensuite windows open a crack, and all condensation is cleared.

If you overventilate the house (ie bringing in too much cold air), then this will in turn reduce the surface temperatures of the house and potentially result in increased surface condensation. How is the incoming air (which has now picked up the moisture from your breathing overnight) getting out of the house? You might need to open a window a crack to provide the end part of that ventilation cycle. It's about finding that compromise for your house, in terms of ventilation rate and heating.

PIV systems are good for dealing with damp issues in landings, internal walls etc, but I don't see them as being the correct answer for condensation on windows. 

Doubleshotdamo

Ben1989 said:

This isn't normal. 

Check your ducting seals or you might have a dodgy unit.

One day just run your unit at power 6 then you know for sure you have an issue!

The unit is fine, installed correctly, freezing cold air blowing out of the diffuser. 

Doubleshotdamo

rob7475 said:

Do you have good ventilation in your loft (can you see daylight at all through the eaves etc?). If the loft is struggling to draw in fresh air, the unit won't be able to do it's job properly

Yes, nice and draughty up there. There's lots of cold air coming from the diffuser. The landing window was free if condensation, my daughters room had a little bit (better than usual) but she complained her room was freezing this morning. 
Downstairs windows were covered in it, as normal, as was our bedroom windows. Oddly, we have a downstairs toilet room, and the window there was covered, usually it's not. 

Doubleshotdamo

ComicGeek said:

Both heat and ventilation are needed to combat condensation. You need to bring in sufficient cold dry air and then heat it, so that it can pick up water vapour - you then need to get rid of that warm moist air, replace with dry air and repeat. If it's just condensation on windows, which can be wiped down in the morning, why bother spending lots of money trying to change that? 

Condensation on bedroom windows with heating off and people sleeping = normal.
Condensation on other room windows = not normal, and would normally mean ventilation/heating issues.

We keep our bedrooms cool to help with sleeping, and don't have the heating on overnight - normally drop from 17 degrees in the evening to 14 degrees in the morning, with night time temperatures of -5 around here at the moment. Condensation on the windows is guaranteed at the moment with sub-zero outside temps, but quick wipe down in the morning in the bedrooms and all good. Our house is now at 19.5 degrees downstairs (bedrooms at 17 degrees), bedrooms, bathroom and ensuite windows open a crack, and all condensation is cleared.

If you overventilate the house (ie bringing in too much cold air), then this will in turn reduce the surface temperatures of the house and potentially result in increased surface condensation. How is the incoming air (which has now picked up the moisture from your breathing overnight) getting out of the house? You might need to open a window a crack to provide the end part of that ventilation cycle. It's about finding that compromise for your house, in terms of ventilation rate and heating.

PIV systems are good for dealing with damp issues in landings, internal walls etc, but I don't see them as being the correct answer for condensation on windows. 

Our living space was nice and warm yesterday evening. I checked the windows (curtains were drawn) and there was condensation about a third of the way up, that was early evening. We went to bed around 11.30pm, so a good 8 hours on no activity downstairs, yet the windows were covered with condensation. All upstairs rooms are now cold with the increased speed of the fan. 
I've now turned it off. 

Apodemus

I've got no experience with PIV, but if you were using a dehumidifier in a property with a long term problem of damp, it might take several weeks before the fabric of the house was drying enough for it to be reflected in the amount of window condensation.  I wonder if this is the same as you are seeing and that the property simply needs more time?