Painting wood/window frame - moisture advice?

[SidneyCasing]

Hi, just looking for a bit of advice.

My wooden windows frames seem to be absorbing moisture in places, noticeable more as the weather is getting colder and condensation is appearing. I am wondering if there is anything I can treat them with before painting? They are wood and varnish atm but I want to sand them down and gloss them. Do I use a sealant? Can anyone point me in the right direction?

www.crownwindows.co.uk/2018/07/how-to-paint-wooden-window-frames/

Some fairly comprehensive information here OP.

Not what you've asked but I thoroughly recommend purchasing an electric dehumidifier. Ours has completely eradicated this issue and collects a great deal of water daily from across the house. Plus laundry dries much quicker. If it were me I'd invest in one and then repaint the windows etc in the spring when they're dried out and it isn't a faff having them open whilst painting.

Another point. If you're sanding/using a heat gun to remove old paint from windows do ventilate and wear PPE. Lots of the older window paints can contain lead and you don't want to be breathing it in.

Not what you've asked but I thoroughly recommend purchasing an electric dehumidifier. Ours has completely eradicated this issue and collects a great deal of water daily from across the house. Plus laundry dries much quicker. If it were me I'd invest in one and then repaint the windows etc in the spring when they're dried out and it isn't a faff having them open whilst painting.

Thanks, i definitely will look into dehumidifiers. The windows are not old at all, 4/5 years, but the sills are just drawing in moisture. It's just wood and varnish but a really bad job. I have already done the fight with the company who installed them and refuse to have them in my house again so just wondered if I could paint them myself whilst we are redecorating the whole room.