Correcting ~10% humidity by closing sun room with fan blowing?

[@JCar]

Hi

I've gotten into orchid husbandry in the last two months and I'm slowly but surely building my collection (expensiveee). I've been reading and exploring obsessively and now I'm looking to close my sum room with a fan circulating air inside to increase the humidity (Johannesburg humidity is around 15% at the moment- winter/spring). This is for about 2 more months until humidity is around %50 again naturally. Will the closed setup cause issues if I air it out for a few times throughout the day (and spray fungicide)?

My children so far:
Vanda chulee no. 5 (vase culture)
Aliceara 'peggy ruth carpenter'
Dendrobium Sea Marion/Sea Mary
Cymbidum Udaigiri
Cymbidium 'twinkie'
Oncidium 'dancing lady's
Paphiopedilum Hsinying Citron
3 Phal hybrids (new medium sized one in bloom with 5 spikes!!)
Cycnodes wine delight
Cattleya Mona Pink 'Hiromi'


Thanks in advance for your time!
Any general advise about these species/genera would also be very much appreciated.