Improving living conditions in my mum's damp and humid small bungalow

[torre]

I'd go dmev, not PIV. PIV pulls fresh air in, which is good, but it's pushing the humid air out via gaps and holes in brickwork, around frames etc. Forcing damp air through the building fabric doesn't sound a great idea

[Crofter]

3 hours ago, minty said:

 A2A heating could be good. Is that the same as an air source heat pump.

 

Yes, it's a different version of ASHP. The outside unit (with the fan) looks the same. It's also the same thing as air conditioning, you're just running it in reverse.

A conventional ASHP heats water for radiators or underfloor heating. A2A heats (or cools) air directly. They tend to be more efficient and easier to install, making them cheaper. The main downside is that there are no grants available for them.

If you're looking for A2A heating, it's easier to just look for air conditioning, it's the same thing.

 

[Iceverge]

9 hours ago, Crofter said:

Yes, it's a different version of ASHP. The outside unit (with the fan) looks the same. It's also the same thing as air conditioning, you're just running it in reverse.

A conventional ASHP heats water for radiators or underfloor heating. A2A heats (or cools) air directly. They tend to be more efficient and easier to install, making them cheaper. The main downside is that there are no grants available for them.

If you're looking for A2A heating, it's easier to just look for air conditioning, it's the same thing.

 

 

I'd be cautious with the unit you buy as those optimised only for cooling may not work efficiently when heating. 

 

I bought a Daikin FTXM25R. 

 

I will update 

 

IF

 

I 

 

EVER

 

MANAGE

 

TO

 

GETTING 

 

AROUND 

 

INSTALLING 

 

IT. 

 

 

[minty]

17 hours ago, SteamyTea said:

?

 

 

When it comes to condensation, the absolute humidity (the grams of water in a kg of air) can become important.

The graph shows that as humidity increases condensation will occur on warmer walls than air with lower humidity which is why there is mould in my mum's house; ventilation and dehumidifiers will reduce the vapour in the air but why is it so high in the first place? How do we find out where it's coming from. Obviously the chalet is wrapped in plastic and there is a dog so is that alone the answer? 

[minty]

3 hours ago, Iceverge said:

 

I'd be cautious with the unit you buy as those optimised only for cooling may not work efficiently when heating. 

 

I bought a Daikin FTXM25R. 

 

I will update 

 

IF

 

I 

 

EVER

 

MANAGE

 

TO

 

GETTING 

 

AROUND 

 

INSTALLING 

 

IT. 

 

 

The mouldy damp living conditions are the primary concern. Will this unit solve the problem?

[minty]

13 hours ago, Crofter said:

Yes, it's a different version of ASHP. The outside unit (with the fan) looks the same. It's also the same thing as air conditioning, you're just running it in reverse.

A conventional ASHP heats water for radiators or underfloor heating. A2A heats (or cools) air directly. They tend to be more efficient and easier to install, making them cheaper. The main downside is that there are no grants available for them.

If you're looking for A2A heating, it's easier to just look for air conditioning, it's the same thing.

 

So what do we do to make the living conditions healthy and free from damp? 

[minty]

15 hours ago, Iceverge said:

 

Probably not enough, 

 

You need 2x windows open to get a decent cross flow. The trouble is then that the house gets cold and they get closed. 

 

 

 

This needs to be on 24/7 a max power. 

 

 

Take this out and replace with one of these. 

 

 

As mentioned above, it runs continuously and ramps up when the humidity does. and sucks out all the damp air. Costs about 1/20th of what a dehumidifier does to run. 

 

Hi

If I run a dehumidifier constantly until the percentage is reduced to 50 , then get my mum and her dog to move out for a few days and the humidity remains the same then does that prove the high air vapour content is caused by the dog and one person?

[minty]

18 hours ago, Roger440 said:

As a short term fix, get a couple of de-humidifiers. If you get dessicant ones, they generate a degree of heat too.

 

Eventually, you will get to a sensible number, say 50%. Once there, see how long it takes to start to rise. If its rapid, then you really need to understand why.

 

Several have said ventilate. Thats great, so long as its lower humidity outside than in. To an extent, thats going to depend where it is, but its been pretty much 90% and over here since mid July here (mid wales) apart from a few notable days. Opening the windows to ventilate would make things worse, not better.

 

I suspect, a lack of ventilation management of any sort just sees the humidity climb ever higher.

 

The above is what i did, the house was humid, mainly as not inhabited for 10 years. It took 6 months of running 2 de-humidifiers to get to the point, where it now sits at 50% and requires, maybe a couple of ours a week of one de-humidifier to keep it there.

So if I get the humidity down to 50% and Mum and dog go away for a few will it stay at 50% even if outside humidity is higher? Surely the humidity inside depends on the humidity outside . How does she maintain a constant 50%- for example- if humidity outside is 80%?

[Crofter]

7 minutes ago, minty said:

So what do we do to make the living conditions healthy and free from damp? 

The choice of heating system doesn't really affect the humidity (assuming you're not using some sort of open flame gas heater, which will spew out moisture). But the advantage of ASHP, of whichever type, is that they convert one unit of electricity in to three or four units of heat, so compared to basic electric heating you can have the house much warmer. Anything you can do to raise the temperature will help.

 

In theory the air movement of A2A might help eliminate dead spots where damp air can linger. But if you under-spec the A2A you can end up with high airflow rates which will lead to noise and drafts.

 

I'm in the process of planning an A2A install myself but can't report back any actual feedback yet...

[Kelvin]

Here’s a reasonable article that might help. Every day living produces quite a lot of water vapour in a typical house (20 litres for a family of four according to this article). Your mum’s small poorly ventilated house with plastic in the walls will keep a lot of this water vapour trapped in the building. 
 

https://www.cityoflondon.gov.uk/assets/Services-DCCS/condensation-booklet.pdf

 

 

Edited April 11 by Kelvin

[SteamyTea]

2 hours ago, minty said:

So if I get the humidity down to 50% and Mum and dog go away for a few will it stay at 50% even if outside humidity is higher? Surely the humidity inside depends on the humidity outside . How does she maintain a constant 50%- for example- if humidity outside is 80%?

It is a bit difficult to track internal relative humidity (RH_I) and the contribution from the outside air relative humidity (RH_O) sometimes.

I suspect you have a leak somewhere, finding it may prove to be hard as liquid water can travel quite a distance from the entry point.

Is there any sign, inside or outside that water is leaking out i.e. a damp carpet, a stain in the bathroom, an odd dripping noise (water meters really help here), staining on the outside cladding.

Worth having a very good look around the windows, especially if they are replacement ones. The vapour control layer (VLC) may have been damaged.

 

2 hours ago, Kelvin said:

Every day living produces quite a lot of water vapour

I seem to remember that a person expires 2 litres a day, not a lot in a big building but quite a bit in a small one.

[SteamyTea]

@minty

 

Are you any good at playing with wires and computers.

For a few quid you can make a multiple sensor temperature and RH data logger.

They come in handy all the time.

 

Thinking about the damp more, it is worth remembering that it takes quite a lot of energy to evaporate liquid water.

Liquid water takes 4.18 kJ/kg.K, to get from liquid to vapour (phase change) takes 2256 kJ/kg.

That is 540 times more energy.

So sometimes drying a place out is much harder than you think.

[Roger440]

3 hours ago, minty said:

So if I get the humidity down to 50% and Mum and dog go away for a few will it stay at 50% even if outside humidity is higher? Surely the humidity inside depends on the humidity outside . How does she maintain a constant 50%- for example- if humidity outside is 80%?

 

If the house was 100% air tight and theres no "leaks of water, then yes, in theory it will stay at 50%

 

However, no house is air tight, and an older house probably very much NOT air tight.

 

My house, even with 2 people living in it, takes a week to go fro 50 to 60% , which, logically is our prescence plus some degree of infiltration from outside, where its currently 99%.

 

A de-humidifier will have a dial to set what level you are targetting. Set it to, say, 50% and just let it sort itself out. Any heat it generates, just means less heat required from whatever other source of heat the house has.

 

If theres no actual water leaks into the house, then to be honest, its a cheap simple fix.

 

You original post suggests the structure is dry, in which case, not much else to do. 

 

More technical, clever solutions are of course available.

 

Edited to add, if its been damp for a long time, it will take a long time to bring it under control as everything thats absorbent in any way, so all the sift furnisjhing, carper, anything made of wood, plasterwork etc will all have settled at the background level. Some of this will take months to dry out.

Edited April 11 by Roger440

[Iceverge]

9 hours ago, minty said:

The mouldy damp living conditions are the primary concern. Will this unit solve the problem?

 

It's just a way of heating the air. Like an electric rad but costs about 4 times cheaper to run.

 

Your mould is caused by poor ventilation. You need to tackle this first. 

[Iceverge]

@minty  Sorry I think I(we) might have git a bit bogged down here in an effort to assist. 

 

Shortest answer I have to solve your problem. 

 

1. Stop any water leaks from outside or inside. ( Roofs, windows, doors, pipes, shower trays, washing machines etc etc)

 

2. Replace the bathroom fan with this. You can DIY it or pay an electrician.

 

3. Make the house hotter by leaving the rads on. 

 

4. Give it time. 

 

 

 

 

 

 

 

[minty]

13 hours ago, Roger440 said:

 

If the house was 100% air tight and theres no "leaks of water, then yes, in theory it will stay at 50%

 

However, no house is air tight, and an older house probably very much NOT air tight.

 

My house, even with 2 people living in it, takes a week to go fro 50 to 60% , which, logically is our prescence plus some degree of infiltration from outside, where its currently 99%.

 

A de-humidifier will have a dial to set what level you are targetting. Set it to, say, 50% and just let it sort itself out. Any heat it generates, just means less heat required from whatever other source of heat the house has.

 

If theres no actual water leaks into the house, then to be honest, its a cheap simple fix.

 

You original post suggests the structure is dry, in which case, not much else to do. 

 

More technical, clever solutions are of course available.

 

Edited to add, if its been damp for a long time, it will take a long time to bring it under control as everything thats absorbent in any way, so all the sift furnisjhing, carper, anything made of wood, plasterwork etc will all have settled at the background level. Some of this will take months to dry out.

Thank you. I understand this post and the way you have described the situation. I like the idea of experiments to make a diagnosis. I will measure the humidity, then reduce it to 50- even if we rent a bigger dehumidifier- then see how long it takes to get back to the original measurement and make a conclusion from there. It would be interesting to repeat this experiment without any dogs or people in the house for a few days and compare results.

There is a very small extension added to living space which I have not explored for leaks etc, however I noticed the mould in there is really bad and the nails in the external cladding are rusty on the extension but not on the original chalet building. I will look inside the walls, floor and roof for signs of excessive moisture. 

Edited April 12 by minty

[minty]

7 hours ago, Iceverge said:

@minty  Sorry I think I(we) might have git a bit bogged down here in an effort to assist. 

 

Shortest answer I have to solve your problem. 

 

1. Stop any water leaks from outside or inside. ( Roofs, windows, doors, pipes, shower trays, washing machines etc etc)

 

2. Replace the bathroom fan with this. You can DIY it or pay an electrician.

 

3. Make the house hotter by leaving the rads on. 

 

4. Give it time. 

 

 

 

 

 

 

 

This is perfect, thank you for your post.  the info on the fan is particularly useful. I'm more focused now.