awful humidity indoors

[Marasme]

we re up North; the humidity inside the house is between 75 and 88% (we have several small humidity meters around the place).

I have a dehumidifier which i run for a few hours everyday to bring the humidity down to 65% in selected areas (mostly my bedroom), said humidity climbs back up to >75% in the morning.

we don t dry laundry indoors
we don t have long baths or showers (we tend to shower at the gym)
the house temp is 16-17 degrees, with the occasional morning blast of heat to 18-19c, and wood burner fire once or twice a week.
we have a new roof
we have new windows
no obvious leak

where does it come from? is it normal?
i m finding it extremely puzzling, annoying and ... uncomfortable

Agree - windows need to opened daily to air the house.

Us breathing out is main source of humidity in my home. Our household temps have also been about 16-18 lately. I also cook, but breathing is main source of wet in air.

thank you everyone!

will respond more methodologically tonight - just back form work

to the PP who asked - humidity outdoors is 99%. it s raining all day, everyday just now.

i have not opened the windows this morning - the rain was horizontal. We possibly have a render problem and this will be the next thing we look into (although i gues snow is not the time for this).

no chance to heat above 18c whilst also ventilating - no budget for this. The dehumidifier seems to be a sort of compromise so far.

no loft insulation, and the loft has veen turned into rooms, so not much space to add insulation except in the eaves.

we also have similar issues with humidity in the summer (but less marked) despite every window being open...

no mold, though, and no sign of raising damp

1. Try to keep the temperature of your house 19-20 degrees. This should bring the RH down to 40-50%. 2. Ventilate, ventilate , ventilate. The windows in my house are open just a little bit in every room all year around. Check if there is no rising, penetrating damp.

I have had the same problem for the last 5 years and tried numerous fixes some helped a little.
Dehumidifier.
Damp proof paint/wallpaper.

In the end I opted to try a nuaire Positive Input Ventilation
expensive but have to say best £450 i have spent.
After 4 days Humidity dropped from 75+ to 45 and the house is so much dryer and fresher .really wish i had done this sooner as would have saved me all the cost of cleaning mold from around windows and decorating.
no more windows dripping anymore.
hope this helps someone