Dehumidifier or PIV or window vacuum or…(listed building)?

caroline1973lefty

Edited cos I have seen on other posts on here, lots of recommendations for PIV systems, v low running costs (not sure about how much more the heated ones cost to run) and people saying maybe esp good for old houses & flats, like mine. Is that a good solution or overkill? (And would you be allowed one in a grade II listed building?)


Friends have suggested I buy a dehumidifier to deal with serious condensation (in winter) on my single glazed windows (it’s a listed building and I have no plans to change those). The condensation is damaging the wood, stone and metal surrounds (I have a mix of sash and metal leaded ones) with corrosion of the metal and recurring mould on all of them. There is no mould on walls. 

I’m a bit worried about energy use running costs/noise of dehumidifier, esp as the problem is in all my rooms (not as bad in living room which is probably warmest and most regularly window-ventilated, but still significant mould on frames) and also whether dehumidifeir is the healthiest and most eco option. Opening the windows more than I already do, and or keeping the bathroom and bedroom radiators on full blast as opposed to low, seems such a waste of heat, and I’m not sure how much it would fix the problem anyway. I confess I have underused the extractor fans in the cooker hood and bathroom - part of the problem is they’re so noisy (they’re quite old) and I’m quite sensitive to ongoing background noise. I also dry clothes inside (have no tumble dryer or outdoor space) and have a gas hob.

I’d be really interested in what people thought my best options might be. I had thought in past about window vac but didn’t know if I’d need to do it every cold day or if it would work enough - though I have just discovered there are little attachments that would work on my leaded panes, I guess. I was sort of thinking that my windows currently perform part of the function a dehumidifier creates anyway - ie, they provide a cool surface where water condenses - so it might be more money saving to use that process, rather than use a machine to recreate it, if you see what I mean? But the small panes throughout do make the hoovering up bit of that, quite fiddly.

or I dunno maybe there’s something else I should do first. Better extractor fans? A tumble dryer?

or PIV?

sorry for long post.

ps - I’m now (first time ever!) the owner of the property, but I have been living in it for along time as the tenant, so I now have more freedom to do work on it, and (in all honesty) more incentive to maintain it brilliantly  - though I *did* do my best as a tenant! 

FreeBear

caroline1973lefty said: Edited cos I have seen on other posts on here, lots of recommendations for PIV systems, v low running costs (not sure about how much more the heated ones cost to run) and people saying maybe esp good for old houses & flats, like mine. Is that a good solution or overkill? (And would you be allowed one in a grade II listed building?)

PIV systems can be relatively low cost to run but.... I recall seeing a post (on the energy board I think) about someone bemoaning high electricity bills. Turns out he had a ~400W heater built into the PIV system that was permanently on. A Mechanical Heat Recovery & Ventilation (MHVR) system would have a lower running cost although the purchase & installation would be more expensive. Depending on where the ducts & vents are located, I see no reason why a PIV or MHRV would not be permitted in a GII building - Have a chat with your local Conservation Officer. He may tell you that LBC is not required.

As for the windows, while you are talking to the CO, run the idea of secondary glazing past him - I know of several people over on the Period Property forum that have secondary glazing, and it makes a huge difference for them. The other alternative might be ultra thin sealed units to replace the existing glass (dependent on CO approval).

BUFF

caroline1973lefty said:
 I also dry clothes inside (have no tumble dryer or outdoor space) and have a gas hob.

I’d be really interested in what people thought my best options might be. I had thought in past about window vac but didn’t know if I’d need to do it every cold day or if it would work enough - though I have just discovered there are little attachments that would work on my leaded panes, I guess. I was sort of thinking that my windows currently perform part of the function a dehumidifier creates anyway - ie, they provide a cool surface where water condenses - so it might be more money saving to use that process, rather than use a machine to recreate it, if you see what I mean? 

Going by my experience (yours may vary depending upon what temp. you keep your rooms at & humidity levels) you would be able to use the window vac pretty much any night/morning that it gets to 3-5C outside or lower. Iirc either Aldi or Lidl has 1 on offer this week for ~£20 so not too expensive to try.
Having said that, hopefully, we are 1/2 way through this winter.

The drying clothes inside may make it worth having a dehumidifier though, if you don't do that in the bathroom with the extractor on. Perhaps a hybrid solution of window vac+ dehumidifier for the room with the drying clothes?

Eldi_Dos

Sounds like your property could be quite drafty with having single glazed sash windows so I am not sure that a dehumidifier is the best place to start. It may seem counter intuitive but I would start by replacing both your extractor fans with newer models with humidstat controls to deal with moisture caused by cooking, bathing and drying laundry. This is one of the most common improvements made when local authorities are upgrading flats. As the windows are something of a cold spot would thermal curtains be a benefit.

twopenny

I'd also ask about secondary glazing.
I used to put clingfilm across from wood to wood inside the frames. It was much warmer and no condensation.
Used the foam draught excluder. Any real ill fitting windows I would screw up lengths of cling film and press into the gaps with a blunt knife. That worked really well and didnt show.

Gers

I've recently had a PIV unit installed in my loft, an old listed stone cottage with double glazed windows. It's made a huge difference even though it's not the heating model. I also use a dehumidifier for drying washing when needed - in one room with the door shut for the duration. 

Certainly you should look to modify or replace your windows as a starting point. Good luck with it all. 

TimSynths

I use Stormguard secondary glazing film on my single glazed windows- no more condensation or draughts, so simple and it works.

3 X DOUBLE GLAZING FILM DRAUGHT INSULATION KIT WINDOWS 6sqm : Amazon.co.uk: DIY & Tools

Goes on in November and I take it off in April.

Bendy_House

caroline1973lefty said:

Friends have suggested I buy a dehumidifier to deal with serious condensation (in winter) on my single glazed windows (it’s a listed building and I have no plans to change those). The condensation is damaging the wood, stone and metal surrounds (I have a mix of sash and metal leaded ones) with corrosion of the metal and recurring mould on all of them. There is no mould on walls.

1) (not as bad in living room which is probably warmest and most regularly window-ventilated, but still significant mould on frames)

2) Opening the windows more than I already do, and or keeping the bathroom and bedroom radiators on full blast as opposed to low, seems such a waste of heat, and I’m not sure how much it would fix the problem anyway.

3) I confess I have underused the extractor fans in the cooker hood and bathroom - part of the problem is they’re so noisy (they’re quite old) and I’m quite sensitive to ongoing background noise. I also dry clothes inside (have no tumble dryer or outdoor space) and have a gas hob.

4) I’d be really interested in what people thought my best options might be. I had thought in past about window vac but didn’t know if I’d need to do it every cold day or if it would work enough - though I have just discovered there are little attachments that would work on my leaded panes, I guess.

5) Better extractor fans? A tumble dryer?

What does one do about too much moisture inside their house? Two things - one is reduce its production in the first place as far as possible, and then ventilate away the remaining.

1) Yes, it's likely to be better in the living room for the two reasons mentioned. Spray mould killer on the frames to sort the other issue.

2) Opening the windows when the heating is on is, indeed, a waste of heat. It would work, tho' - ventilation is key - but it is a waste of heat. Instead, wait until the heating is off - ie overnight - when I bet most of the condensation forms anyway? Crack open the bedrooms windows, and get under yer duvet. First thing in morn, get someone to shut the windows...

3) Change that to over-use extractors in the kitchen and bathroom. Where do these vent out to - the wall or the roof? If the latter, do you have access to the loft space? If so, consider (if needed) upgrading the bathroom extractor, possibly up to 5", and in-line with the fan suspended on cords nicely away from the ceiling vent = less noise. Either leave it running for 10 minutes after any moist use, or get a timer model (tho' you probably won't want it running every time you have a weewee). There are also humidistat models.

You need to DO this, every time. That's half the cause.

4) Window vac or an absorbent cloth - either. It'll take you 5 minutes to wipe up all the cond each morning - not a biggie. In any room you then don't use during the day - bedrooms, for example - crack open the windows to 'vent' position, turn off the heating, and shut the door. When you next go in there, it'll be bone dry. In the evening, before the bedroom rads come on, close the windows to retain heat. When it's bed time, and after the rads have gone off, crack open a window to vent position and jump into bed. I'll bet you you'll have a hugely reduced amount of cond in the morning.

5) Yes. And yes. First, USE the extractors you have. If they are underpowered, then consider upgrading them if it's cost-effective. Tumble drier? Of course! Venting outside if you can, or a condensing model (not as good, but hey) if you cannot. Do NOT dry your clothes in the air in your flat.

PIV? I understand they work well, but why would you want to do this when you can almost certainly achieve a major improvement by doing simple, often free, things? Dehumidifiers? Nasty nasty things - noisy, ugly, yuck. They should only be needed when you've had a water disaster - they should not be required for day-to-day living.

Cut down the water production. Ventilate away as much as you can when you can - bedrooms overnight and during the day. Mop up all remaining cond each morning, finish with a paper towel so's it's fully dry, and give regular sprays of mould-killer on any stubborn mouldie bits.

And wait for Summer :-)

PollyWollyDoodle

I had a PIV unit fitted in my last house and it was amazing - mould and condensation problems disappeared completely.  Noiseless, cost very little to run and I hardly knew it was there. A friend who is a landlord had told me about them, he fits them in all his rental properties. I’m planning to have one in my current house later this year when I have some work done.

caroline1973lefty

thanks thanks so much, some really helpful advice here. I think I’ll investigate getting better (quieter) extractor fans so I can bear to use them consistently, and perhaps venting the windows a crack overnight and see what difference that makes - I live on an upper floor in a very safe area but I’ve always been a little bit jumpy about security, but that’s probably a bit silly. I do really like the feeling of a chilly bedroom under a nice hefty duvet, seems healthier and less stuffy for sure! And I’m off to check out the cheapo window vacs now. But I might do a bit more research into PIV running costs too. And maybe either a tumble dryer or a dehumidifier… this is possibly an absurd question, but I wonder which would actually use more energy to dry a load of clothing? (Tho actually a lot of my clothes are wool or delicates so they have to be air-dried anyway). 

Bendy_House

Yup, I like the cool breeze blowing across your nose when snug under a duvet too. Great feeling.

If you try that just once, you'll see that it works. Bedroom heating off or very low all night, and window cracked open. You should find a HUGE reduction in condensation on the window the following morning. Have the heating still coming on a half-hour before you get up, and if you like a lay-in, just jump out and close the window and jump back under with a cuppa, because the job will have been done.

When you leave the bedroom for the day, by all means crack open a window again and leave the heat off in there - it'll be completely dry come the next bedtime.

Yes, a tumble drier will have running costs, but probably not that much - 30p a load? I dunno. But the whole reason for it is that you don't have the problems you currently have.

It might be that drying your clothes in the room air will be ok provided you start ventilating the room more. But there's no point doing this to save a few pennies if it means you have running windows and mould.

If you have a spare bedroom, you can even try setting up your clothes in there on a 'orse, and leaving the window(s) nicely open to allow a proper breeze through there - heating off, door closed; let the room get on with it, and there will be no condensation because t'll all have been ventilated away. If it's proper cold, tho', good chance your clothes will remain a bit damp, so you can then bring it in to the warm rooms for a final airing.