Is condensation in the loft reduced by having central heating on?

[ZACCCC]

I've got a problem with condensation in my loft and I was wondering whether having central heating on throughout the house, as opposed to just using a gas fire downstairs, would increase condensation in the loft or decrease it. I'm an OAP and live on my own and therefore I try to cut down on heating costs by mainly just using the fire in the living room rather than heating the whole house with the CH.

However, I'm now wondering if my thriftiness is creating condensation problems for me. The theory, as I understand it, is that warm moist air caused by cooking, washing and even just breathing rises eventually into the loft and when it reaches the cold surface of the roof felt it forms condensation. Now, if your house has its CH on presumably that will extract the moisture out of the air and therefore less warm moist air will rise into the loft to form condensation. Am I right here? Or am I missing something? Any advice would be welcome. Thanks.

 

[endecotp]

if your house has its CH on presumably that will extract the moisture out of the air

No, central heating does not extract moisture from the air.

But if the whole house is warmer, maybe the loft will also be warmer and there might be less condensation as the surfaces are less cold.

If you're suffering from condensation in the loft, I suspect the first thing to do is to check for sufficient ventillation in the loft.

 

[vinn]

A first prevention against condensation is to have trickle heating in all rooms, and trickle ventilation in all rooms.
Two powerful extractors in bathroom and kitchen, and read the massive info on here about what you ask.

 

[^woody^]

You don't have a condensation problem, rather a ventilation problem. And probably inadequate insulation.

 

[JohnD]

//www.diynot.com/diy/threads/condensation-in-loft-answers.160032/

 

[KenGMac]

ZACCCC, good evening.

Your hypothesis as regards the Science behind water vapour and how it occurs to form Condensation in cold areas is good the rational is correct in that water vapour will condense in cold places, such as wall to ceiling corners in unheated bedrooms, indeed any cool rooms where ther is little or no air movement. air movement plays a big part in halting condensation occurring.

As an aside, there is a lot of information on the Board in the Floors stairs and lofts section suggest you have a look??

Back to your question, there are several things that you may wish to consider??

1/. After a Shower, open the window in the bathroom, BUT that will cause a loss of heat in the room, BUT will remove the so called "Free Water" [Steam] from the room and the house, BUT, to maintain a reasonable house temperature close the window after about 5 Mins, even if you set a timer to remind you?

2/. In the kitchen you could consider installing an extractor which vents the steam and water laden air from the cooker directly to the outside of the Building, after all when cooking Pasta, Potatoes, anything that produces Steam "Free Water" the vast majority of extractor hoods simply recirculate the hot wet air into the house, hence the "free Water" load is increased greatly.

3/. In the loft area, you could consider installing ventilation? which generally entails installing purpose made roof vents which are fitted near the eaves and at the ridge, these vents ensure an air flow inside the loft space, that sounds crazy? but if there is a good level of Insulation in the loft??? [what depth of insulation do you have?] there is no problem, in that the Insulation keeps you warm, the vents in on the roof ensure that there is no roof void Condensation.

Lets see what the board has to say about this? but hope this gives food for thought?

Ken.

 

[^woody^]

Loft condensation is not from condensation in the rooms below

It's from heat.

 

[JohnD]

the vast majority of extractor hoods simply recirculate the hot wet air into the house

Surely not.

An extractor has to suck the steam and fumes out of the house. A recirculating hood serves no useful purpose.

 

[ZACCCC]

No, central heating does not extract moisture from the air.

But if the whole house is warmer, maybe the loft will also be warmer and there might be less condensation as the surfaces are less cold.

If you're suffering from condensation in the loft, I suspect the first thing to do is to check for sufficient ventillation in the loft.

I take your point about ventilation in the loft and I'm in the process of getting a roofer to put vented roof tiles and/or vented eaves trays in my roof. However, I'm not sure about your assertion that CH doesn't extract moisture from the air. I'm thinking of the things people say about CH drying things (and themselves) out and the advice about leaving a bowl of water near a CH radiator to rehumidify the air.

 

[ZACCCC]

ZACCCC, good evening.

Your hypothesis as regards the Science behind water vapour and how it occurs to form Condensation in cold areas is good the rational is correct in that water vapour will condense in cold places, such as wall to ceiling corners in unheated bedrooms, indeed any cool rooms where ther is little or no air movement. air movement plays a big part in halting condensation occurring.

As an aside, there is a lot of information on the Board in the Floors stairs and lofts section suggest you have a look??

Back to your question, there are several things that you may wish to consider??

1/. After a Shower, open the window in the bathroom, BUT that will cause a loss of heat in the room, BUT will remove the so called "Free Water" [Steam] from the room and the house, BUT, to maintain a reasonable house temperature close the window after about 5 Mins, even if you set a timer to remind you?

2/. In the kitchen you could consider installing an extractor which vents the steam and water laden air from the cooker directly to the outside of the Building, after all when cooking Pasta, Potatoes, anything that produces Steam "Free Water" the vast majority of extractor hoods simply recirculate the hot wet air into the house, hence the "free Water" load is increased greatly.

3/. In the loft area, you could consider installing ventilation? which generally entails installing purpose made roof vents which are fitted near the eaves and at the ridge, these vents ensure an air flow inside the loft space, that sounds crazy? but if there is a good level of Insulation in the loft??? [what depth of insulation do you have?] there is no problem, in that the Insulation keeps you warm, the vents in on the roof ensure that there is no roof void Condensation.

Lets see what the board has to say about this? but hope this gives food for thought?

Ken.

 

[ZACCCC]

Thanks Ken for your long answer. I'll have a look at Floors, stairs and lofts section, as you suggest.

As regards no.1, I do open the window after having a bath, usually for more than 5 minutes and I also have an extractor fan going while I'm in the bath but it still takes much longer for the condensation to disappear.

No.2: I already have an extractor fan in the kitchen and also I use pan lids when cooking, which also reduces steam.

No.3: I'm actually in the process of searching out a roofer to do exactly what you suggest i.e. installing vented roof tiles and also vented eaves trays, but it's always reassuring to have your own thoughts supported by others' opinions so thanks anyway for that.

I'm still not clear whether using CH for the whole house rather than just using a living room fire would help solve the problem or make it worse but thanks for your input.

 

[ZACCCC]

ZACCCC, good evening.

Your hypothesis as regards the Science behind water vapour and how it occurs to form Condensation in cold areas is good the rational is correct in that water vapour will condense in cold places, such as wall to ceiling corners in unheated bedrooms, indeed any cool rooms where ther is little or no air movement. air movement plays a big part in halting condensation occurring.

As an aside, there is a lot of information on the Board in the Floors stairs and lofts section suggest you have a look??

Back to your question, there are several things that you may wish to consider??

1/. After a Shower, open the window in the bathroom, BUT that will cause a loss of heat in the room, BUT will remove the so called "Free Water" [Steam] from the room and the house, BUT, to maintain a reasonable house temperature close the window after about 5 Mins, even if you set a timer to remind you?

2/. In the kitchen you could consider installing an extractor which vents the steam and water laden air from the cooker directly to the outside of the Building, after all when cooking Pasta, Potatoes, anything that produces Steam "Free Water" the vast majority of extractor hoods simply recirculate the hot wet air into the house, hence the "free Water" load is increased greatly.

3/. In the loft area, you could consider installing ventilation? which generally entails installing purpose made roof vents which are fitted near the eaves and at the ridge, these vents ensure an air flow inside the loft space, that sounds crazy? but if there is a good level of Insulation in the loft??? [what depth of insulation do you have?] there is no problem, in that the Insulation keeps you warm, the vents in on the roof ensure that there is no roof void Condensation.

Lets see what the board has to say about this? but hope this gives food for thought?

Ken.

Sorry, you asked about my insulation. As far as I've been able I've put in 12 to 13 inches throughout.

 

[chappers]

I'm not sure about your assertion that CH doesn't extract moisture from the air. I'm thinking of the things people say about CH drying things (and themselves) out and the advice about leaving a bowl of water near a CH radiator to rehumidify the air.

Never really understood that one, warm air holds more moisture than cold but yes heat can evaporate moisture, but only if it's got somewhere to go.
If you put some water in a plastic bottle and leave it in the sun to warm up, what happens? Yes the water evaporates but it re-condenses on the inside of the bottle but doesn't leave the system, but if you leave the lid off the bottle it will all eventually evaporate away. Your house is the same, if the vapour in the air is carried away then it won't re-condense and cause condensation.
Warming the air via central heating will just allow the air to hold more water vapour and when it cools down again it will then condense back out, unless it is carried away by ventilation

 

[ZACCCC]

Never really understood that one, warm air holds more moisture than cold but yes heat can evaporate moisture, but only if it's got somewhere to go.
If you put some water in a plastic bottle and leave it in the sun to warm up, what happens? Yes the water evaporates but it re-condenses on the inside of the bottle but doesn't leave the system, but if you leave the lid off the bottle it will all eventually evaporate away. Your house is the same, if the vapour in the air is carried away then it won't re-condense and cause condensation.
Warming the air via central heating will just allow the air to hold more water vapour and when it cools down again it will then condense back out, unless it is carried away by ventilation

Thanks mate. I still don't think I completely understand how it works but your explanation has certainly given me food for thought. So the CH warms the air up and it is now able to absorb more moisture. But you would think that anybody breathing that air would now be absorbing more moist air when they breathe and yet people blame CH for drying them up(?)