PIV loft mounted units

[transatlantic]

I'm looking into getting one of these to hopefully help reduce a lot of the cendensation I get in my bungalow. It doesn't suffer from damp, but in cold weather, I generally wake up to all my windows soaking wet at the bottom due to the condensation build up over night.

I appreciate that a site survey will need to be undertaken by the company I choose to fit it, but has anyone had one installed? did it solve the problem? any pros/cons?

 

[Rorschach]

Be prepared for a big increase in your heating bill.

Bungalows (single story properties in general) will usually suffer from condensation. Get a dehumidifier, it will save you an awful lot of money.

 

[transatlantic]

A dehumidifier that can handle the whole house is also not going to be cheap to run though?

 

[Rorschach]

You don't need a large one for your purposes, big ones are only needed when drying a water damaged property, you are just looking to control the humidity levels.

There are also lots of lifestyle habits you can change to reduce moisture in the air, they will make a big difference as well.

 

[Blackswanwood]

I think you can get these as part of a heat recovery unit so arguably heating costs would not go up. This is where we miss the input of MikeG.

 

[Rorschach]

I think you can get these as part of a heat recovery unit so arguably heating costs would not go up. This is where we miss the input of MikeG.

Be wary of the efficiency figures quoted on those, they are in optimal situations in purposely designed homes that been leak tested and sealed.

 

[transatlantic]

There are also lots of lifestyle habits you can change to reduce moisture in the air, they will make a big difference as well.

Yes, I have tried those. But I don't think that is the issue. I live alone, so one bath a day, and I don't dry clothes or anything indoors.

 

[artie]

Was in your position one month ago.
RF in the bedroom in the morning up to 85%
Bathroom the same almost all the time, unused rooms musty ( is that a word?) smell
I bought one of these
https://www.amazon.co.uk/gp/product/B005J3334I/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1
and replaced my previous rather pathetic bathroom ceiling fan. I hooked it up to a humidistat.

I then bought one of these.

https://www.amazon.co.uk/Meaco-12L-...&qid=1604415443&sprefix=meaco+,aps,202&sr=8-3
I leave it on in the bedroom all day and put it out in the hall at night. it's quiet but not quiet enough to sleep with. I did a rough calculation, if it ran 24/7 it would cost around 75p per week. (Edit to add £5 per week)
I empty around a litre of water out of it twice a day. Volume of water is decreasing as the old house dries out.
It will be in use 1 month tomorrow. rh in the bedroom is low 50s and sometimes in the high 40s.
The bathroom is always mid 50s except immediately after showering, but returns to mid 50s quickly.

Quite cheap solution and no new holes made.

I intend once the house is dried out to put the dehumidifier in the penthouse and circulate the dry air to the bedrooms.
75p max ( edit £5 ) per week is a paltry sum to keep the house dry.

 

[Cabinetman]

Hi Artie, yes that’s exactly what I did fitted a chunky fan unit in the hose and then a dehumidifier, mine is a desiccant type but I’m not sure what difference that makes. Another thing I do is to collect the water and supply it to my local charity shop for their clothes steaming machine, Ian

 

[Rorschach]

Hi Artie, yes that’s exactly what I did fitted a chunky fan unit in the hose and then a dehumidifier, mine is a desiccant type but I’m not sure what difference that makes. Another thing I do is to collect the water and supply it to my local charity shop for their clothes steaming machine, Ian

Desiccant cost more to run but work down to very low temperatures. Compressor types are cheaper and more efficient but only when the ambient temp is high enough.

 

[HappyHacker]

I put a PIV in for a customer with an old sandstone farmhouse. He had done all the standard damp prevention measures but two foot thick sandstone walls were still slightly damp, his damp specialist recommended a PIV. He was very happy with the result.

Not sure about if it would work in your situation but it would increase air changes (and heating bills?) so you should see an improvement. The suggestions above for a dehumidifier or heat recovery may be more reliable.

Are your windows double glazed?

 

[transatlantic]

Was in your position one month ago.
RF in the bedroom in the morning up to 85%
Bathroom the same almost all the time, unused rooms musty ( is that a word?) smell
I bought one of these
https://www.amazon.co.uk/gp/product/B005J3334I/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1
and replaced my previous rather pathetic bathroom ceiling fan. I hooked it up to a humidistat.

I then bought one of these.

https://www.amazon.co.uk/Meaco-12L-...&qid=1604415443&sprefix=meaco+,aps,202&sr=8-3
I leave it on in the bedroom all day and put it out in the hall at night. it's quiet but not quiet enough to sleep with. I did a rough calculation, if it ran 24/7 it would cost around 75p per week.
I empty around a litre of water out of it twice a day. Volume of water is decreasing as the old house dries out.
It will be in use 1 month tomorrow. rf in the bedroom is low 50s and sometimes in the high 40s.
The bathroom is always mid 50s except immediately after showering, but returns to mid 50s quickly.

Quite cheap solution and no new holes made.

I intend once the house is dried out to put the dehumidifier in the penthouse and circulate the dry air to the bedrooms.
75p max per week is a paltry sum to keep the house dry.

Interesting.

Not sure about your maths though?

165w an hour is about 4kw a day, so 28kw a week.
28 * 15p = £4.20 a week.

Unless of course you're getting a cracking deal on your electricity

 

[transatlantic]

I put a PIV in for a customer with an old sandstone farmhouse. He had done all the standard damp prevention measures but two foot thick sandstone walls were still slightly damp, his damp specialist recommended a PIV. He was very happy with the result.

Not sure about if it would work in your situation but it would increase air changes (and heating bills?) so you should see an improvement. The suggestions above for a dehumidifier or heat recovery may be more reliable.

Are your windows double glazed?

I'm sure a dehumidifier would help, but it feels like a bit of a work around as opposed to a solution. I'll have to look into the running costs of a PIV that also heats the air too.

They are double glazed but they're super old by now, I'd guess at least 20 years old.

I've also done some experiments with leaving a window or two open over night, but it didn't help. I suspect because there isn't actually a a flow of air going in/out.

 

[artie]

Interesting.

Not sure about your maths though?

165w an hour is about 4kw a day, so 28kw a week.
28 * 15p = £4.20 a week.

Unless of course you're getting a cracking deal on your electricity

You are quite right I got confused I recently calculated costs for a few low watt items.
Still a fiver a week is still well worth it imo.
As the house dries out it will be on less and less.

 

[Rorschach]

Running ours probably costs about a £1-2 a week I reckon, we use it a few hours a day, but we only use it in the winter months so about 1/2 the year and it's definitely worth it.

 

[porker]

I live in a big old house that is predominantly single glazed and we had a few humidity problems. I fitted a PIV and we have had good results. Ours has a heater but I've never used it. Been running it for 3-4 years andonly switch it off in the Summer when it is drawing hot air from the roof space which I don't want. I know there are a few people who don't believe in them (including Peter Ward who I have a lot of time for) but it definately improved things for me. I also need to improve extraction from my bathroom and had been looking at the fan that artie points out. My biggest issue is venting to the outside as my house roof doesn't lend itself to venting out of the soffits (I don't have any). Not sure venting into the roof space is a good idea. Fitting a heat recovery system would be nice but retrofitting to an existing building would be a challenge in a lot of cases.
I would go the dehumidifier route as well if I were you as the reduction in humidity makes the house feel warmer irrespective of the actual temperature, prevents mould etc.

 

[artie]

My biggest issue is venting to the outside as my house roof doesn't lend itself to venting out of the soffits (I don't have any). Not sure venting into the roof space is a good idea.

I'm pretty sure there's a vent available that replaces a tile or slate.

 

[artie]

I'll have to look into the running costs of a PIV that also heats the air too.

I don't think you're going to get much heat benefit, even 1 kw would hardly be noticeable in the volume of air you need to shift.
What tipped the balance in favour of the dehumidifier for me was, although it uses 160 watts it is making the air easier to heat because the moisture content is lower.
I may get some of that back in reduced heating bills.
also with the PIV you are forcing out warm air and bringing in cooler air, with the dehumidifier the air stays put.

 

[Rorschach]

with the PIV you are forcing out warm air and bringing in cooler air, with the dehumidifier the air stays put.

I tried to argue this on a thread a while back and was roundly shouted down by certain members, they couldn't seem to see the benefit of keeping your nice (expensive) warm air inside the house and were insistent on blowing it outside instead.

 

[artie]

I tried to argue this on a thread a while back and was roundly shouted down by certain members, they couldn't seem to see the benefit of keeping your nice (expensive) warm air inside the house and were insistent on blowing it outside instead.

My Ulster Scots blood won't let me waste things, lol.
I have a wood burning stove in the sitting room, I have an air intake which brings in air from outside to fuel the fire without taking nice warm air from the room.
The trouble I had convincing the fitter what I wanted was unbelievable.