Bedroom always smells 'stale'

[NoNameNoGame]

We sleep with our windows open all year round and leave them open during the day. I wash the bedsheets once a week and use candles (which help temporarily) and have a reed diffuser. I shake down the pillows and duvet every morning. What am I doing wrong?

We had a similar issue and we found that replacing the AAV valve on the soil stack sorted it. It wasn't a mouldy mildew smell, it was sort of a musty old washing smell.

I couldn't remember exactly how the Air Admittance Valve worked but found this which explains it on the Screwfix forum.

"The aav works on the principle of negative pressure in the stack will lift the diaphragm and allow air in the stack.

What can happen, after months or years of use, the steam and vapour from baths etc. can make th diaphragm sticky, and when it lifts to let air in, it sticks and lets sewer gas out! "

Put DH in the washing machine?!