Like a lot of houses, we’ve got a bit of a condensation problem. Unfortunately, we recently replaced all our loft space with a bedroom so we can’t fit a PIV (apparently). What’s been recommended is something called a “heat retention alternate flow” (not SRHRV), but I’m struggling to find much in the way of information. Looks like they are a per room solution rather than a whole house set up. Anyone got any experience of these units?

TIA

I think they might be thinking of a MIV system – this creates a draft in rooms to redistribute the warm air that collects at the top of a room.

So a fan then?

Try speaking to these guys, they were very helpful with me.

This is what they have on their website

https://www.dryhomes.net/Flatmaster_2000_R/p4194111_16418390.aspx

I assume would work in a house.

IMO the PIV works more because it creates air circulation than massively reducing humidity.

That one might work FD, will take a closer look. Is it critical where they are installed?

following with interest.

Weve recently got the entire roof replaced as we were having significant damp issues in our house. Its cost a bloody fortune.

thing is theres still 4 months on) a significant amount of condensation occurring. I believe this is from several issues.

1. cold walls.?
2. we have several showers a day and even though we have a constant running extractor i still believe it has an impact.
3. we dry clothes in a room with an open window.

Weve bought a washer dryer so we can dry stuff like towels. but id be interested on others views on how to reduce the condensation.

andybrad – Member
following with interest.

thing is theres still 4 months on) a significant amount of condensation occurring.

How about the kitchen/cooking?
Do you have an extractor hood that extracts to the outside?
And do you keep pan lids on etc…?

Also, does the extractor in the bathroom actually work?
What type is it and how much ducting do you have? We had an cheap axial extractor put in to replace a failed centrifugal extractor and it wasn’t able to overcome the resistance of the pipework to create any flow. So, while it made the right noises, it wasn’t doing anything. We replaced it with a centrifugal extractor (the same that had failed) and that actually worked.

I live in a 3 bed semi with loft converted. 5 people in house. In winter all Windows closed. Clothes dried indoors on ceiling rack at top of stairs.
Point of above = a lot of moisture/condensation.
We run a dehumidifier all winter in hall. Costs pennies a week. We have zero condensation issues in any room.
I’m tight with the heating too so bedrooms etc. often cold which would result in condensation issues.

When you guys say ‘condensation issues’…..do you mean like wet windows in the morning? Or wet walls?

Wet windows and damp walls (chimney breasts particularly) for us

wet windows.

used to be wet walls before we got the roof done

You’d be surprised how much water is removed with a dehumidifier even in a dry house. We tend to run ours in the winter due to drying clothes on radiators

woody2000 – Member
Wet windows and damp walls (chimney breasts particularly) for us

SAME HERE. hence the new roof!

also weve had that cavity insulation which has marginally helped but obviously theres no cavity in a chimney breast

jumping in on this thread.

My cottage has a bit of a moisture problem. 1820’s cottage, original roof space occupied by a 1970’s full dormer so no roof space. previous owners installed UPVC windows and blocked up the fireplaces (but not the chimneys) so it’s not massively damp, but some cheap humidity meters do read between 75-85% constantly.
We run a dehumidifier, but are looking for a better solution as we get some mould staining on the ceiling in bedrooms which needs cleaned off periodically, but not often, and the bathroom as we don’t have an extractor.

Moisture from the bathroom can be managed by a decent extractor fan, question is, do I go for a manrose centrifugal type, or am I better getting some heat recovery ventilation system with a booster, like this:
heatsava

in addition, the flatmaster mentioned above, that may work for a PIV type solution for the rest of the house as it’s mostly moisture from breathing.

It’s only a small cottage and supply and fitting both will probably come in at under £800, so worth a go?
cheers 🙂

Modern lifestyles and hermetically sealing houses with airtight windows, capped non-functioning or closed functioning chimneys and old buildings are the primary reasons for condensation. Other details such as repointing and weatherproofing masonry with a Portland product as opposed to lime based mortars and renders also contribute.

Ventilation.

Either passive or forced, probably depending upon your needs for your home and lifestyle.

Alternatively, reopen your fireplaces and use them as your primary source of heat and refit the old windows and doors to let the air in 😀

Ventilation

This. Doubly so for the “1820’s cottage.” Modern building practices are death to an older house.

https://www.heritage-house.org/damp-and-condensation/managing-damp-in-old-buildings.html

Both houses I’ve lived in are over 100 years old and have needed damp management. Old houses soak up a lot of moisture so have to be able to breathe it out. Easily done by leaving window vents open all year round. You’ll be surprised how warm it is when you aren’t trying to heat up damp walls.

I use one of these (https://www.amazon.co.uk/gp/aw/d/B01DC2ZXR2/) behind the sofa where I still get a little damp.

Opening up the chimneys will create a massive flow of air. If you can live with the extra heating cost it’ll cure the damp. Bathrooms need a decent fan and short, rigid pipes if routed in the attic. Still need to get a round tuit.

My plan is to open the main fireplace in the living room, it’s not plasterboarded over, just covered in thin ply as a cover up job. Been gettin quotes for making the fireplace OK for a multifuel stove but this is slightly out of budget, next door neighbours got theirs done for around £1k, we’ve been quoted £3k, but it’s obviously not like for like.

The fireplace in the kitchen has the electric meter and distribution board in it. But this one does have an open vent to the chimney itself, so not too concerned about that.

The floors don’t have carpets, we removed these, predominantly as they were cream coloured and we have a black dog and a muddy MTBer, but they do let the house breath a bit more. we also keep the trickle vents open all year round too.

In a perfect world where we have budget I’d either strip the walls back downstairs and make sure they’re lime plastered. I quite like the crooked look anyway and I think the cottage has lost a fair bit of character from being modernised.

The upstairs dormer is essentially a STW large shed sat where the roof should be, but collects miosture as it only has the window trickle vents for ventilation.

For the moment I’m just gradually trying to manage the indoor air quality as best I can with a small budget. The PIV type systems seem attractive for a ‘on all the time’ solution as you’re not sucking warm air out of one room.

I guess a decent bathroom fan, will be a first stop for getting rid of one of the principle sources of moisture.

🙂

We live in a 200yr old cottage in Cumbria. So it’s permanently damp 😕
We suffered from condensation upstairs. Got a very good damp expert in who said he could charge me a fortune for various solutions but he simply advised to crack open all the upstairs windows slightly. We did this and for 12 months we have been condensation free.

so, got some posiive advice about the Flatmaster 2000 for our cottage and it’s a goer. not to sort the bathroom fan…budget is probably about £40-70 and it needs to be a through the wall jobbie.

manrose centrifugal
here

or something like this:
https://www.screwfix.com/p/xpelair-c4tr-12w-simply-silent-contour-bathroom-extractor-fan-with-timer/4268f

ta

Not really a fan 🙄 of Manrose stuff. I’d go for Xpelair.

ok ta

lovewookie – we had that Manrose centrifugal fan in our previous house. Due to the length of ducting in the loft, an axial fan couldn’t generate enough pressure to move the air.

It worked well & cleared the bathroom well, but can’t really say if it would be better than the axial Xpelair you link to. If it’s through a wall, you shouldn’t have masses of pipework to deal with.

The Manrose one isn’t loud, but is noticeable & takes up quite a lot of space, given that the guts of the device are in a box that has to sit in the bathroom space.

I have the xpeliair one as a replacement in my bathroom. Def set it up on the higher rating of flow, mines was on the lower setting and it doesn’t quite shift enough.

Looks like a new bathroom fan will be needed at ours too. After investigation, we have discovered that the fan in the downstairs shower is simply extracting in to the roof space. A roof space that is now 95% smaller than it was when we moved in! D’oh 🙂