keeping boiler on all time saves money

rogerblack

Cardew wrote: »

I am a little puzzled by the advice in the articleabout heating unoccupied rooms to prevent mould.

If an unoccupied room becomes damp it is because there is an inherent problem. All heating a room achieves is for the air to hold more moisture and initially mask the problem.

Indeed mould is a far bigger problem for properties in sub-tropical/tropical climates.

If there is a problem of dampness in an unoccupied room that cannot be cured, it would be better to use a small dehumidifier than keep it heated.

I missed this part of the article somehow.

Stating there is an 'inherent problem' isn't really accurate.
Condensation is a natural phenomenon when air meets a cold surface.

If you have air at 25 degrees C and 50% humidity, and cool it to 14C, then it will condense.
50% humidity is not unreasonable.

The 'problem' here is that you have different temperatures.

Ventilation is an alternative way to remove the excess humidity, and may work out less expensive. (dehumidifiers are far from cheap to run).

Cardew

rogerblack wrote: »

I missed this part of the article somehow.

Stating there is an 'inherent problem' isn't really accurate.
Condensation is a natural phenomenon when air meets a cold surface.

If you have air at 25 degrees C and 50% humidity, and cool it to 14C, then it will condense.
50% humidity is not unreasonable.

The 'problem' here is that you have different temperatures.

Ventilation is an alternative way to remove the excess humidity, and may work out less expensive. (dehumidifiers are far from cheap to run).

Roger,

I am not sure you have read my post correctly as I didn't mention condensation! - which of course occurs ' when (warmer) air meets a cold surface.'

If the unused room is not heated there will be less of a differential between the air and an outside surface. In places like Canada unoccupied buildings(hunting lodges etc) are winterized by draining all water and leaving the interior temperature to drop well below freezing.

Indeed there was a programme on TV about the hut Scott(of the Antartic) used. It is 100 years old and the contents are undamaged.

I have a little used detached annex that I don't heat at all when unoccupied, unless there is a danger of freezing. In winter the temperature might drop to 2C without any sign of dampness.

The article suggests that you heat the unused rooms to prevent dampness. If you need to do this the warm air will hold more moisture and condensaton will occur if there is an inherent problem. - The inherent problem to which I refer could be lack of ventilation or ingress of moisture.

With regard to the use of a dehumidifier, I stated that it would be better to use one if there was a problem of dampness.

P.S.
Not sure of the relevance in this context of cooling a room to 14C from 25C.

rogerblack

Cardew wrote: »

Roger,

I am not sure you have read my post correctly as I didn't mention condensation! - which of course occurs ' when (warmer) air meets a cold surface.'

If the unused room is not heated there will be less of a differential between the air and an outside surface. In places like Canada unoccupied buildings(hunting lodges etc) are winterized by draining all water and leaving the interior temperature to drop well below freezing.

This works because the humidity is well below 100%, as the room equilibrates in humidity with the outside.

In the case of an unheated room, this may not be the case - unless ventilation to the outside is significantly more than the ventilation or leaks from the heated volume in the house.