Dehumidifier and loft question

[DoodleMum12]

This is a bit of a weird one! Last year I got a dehumidifier and not long after I noticed droplets on the inside of my roof (in the loft) this happened when we had snow. The only thing we did different last year was the dehumidifier. We got a roofer out and he installed 4 vents ans no issues since .
In the last few days I have used the dehumidifier again and we’ve had some frost and today I noticed some droplets of water on the roof felt in my loft. Nowhere near as bad as last year but have been using the dehumidifier a lot in the recent days. I’m wondering if they might be connected . I know it’s a weird one!

If anything using a dehumidifier will make your house less humid, so air that rises into the loft should be less humid.

However lofts are pretty open anyway or at least should be if they are vented.

Has the dehumidifier caused you to change your behaviour in other ways ? For example maybe you are now running your house colder because it doesn't feel as damp.

What humidity level is your house in general ? I keep mine about 50%, but the loft is currently about 75% and outside it is 94%.

Could it just be that you are using the dehumidifier when the weather is colder and damper, and that is when the loft is more likely to show evidence of condensation?

@GasPanic it’s usually between 50-60. I haven’t changed anything else, in fact I keep the home warmer overnight so that the house is at a constant temperature of around 16 at night and 18/19 in daytime . I wasn’t doing this last year

@ClematisBlue49 it’s weird as I never noticed droplets before and we’ve been in this house 22 years.

I’m wondering if it’s because my bathroom is extremely warm when the dehumidifier is on the that’s where the loft hatch is. It’s not insulated so maybe that’s the problem- more heat is entering the loft. I really need to sort some insulation. This has given me the push to register for the government grant check so this is now with EDF and we will see what happens, hopefully they will at least send someone out to survey it and give us a quote. I need to at least insulate the hatch!

Thank you for responding 🙂

Just to help you. Warm air from within the house is rising (this is what hot air does) and it is then condensing on a cold surface. More insulation on the floor of the loft will help to stop the heat from escaping into the loft.

Nothing to do with the dehumidifier, just warm air hitting a cold surface.

When the weather is frosty and the air is still it will get very cold in the loft ( night) frosty nights usually lead to sunny days so as soon as the sun comes out the temperature in the loft can rise quickly, if there is no wind to give airflow through the loft then it can lead to condensation.