Re: Terrariums.
Look at temperature regulated Basking Rocks, or under case heating pads. A cloth pad or spacer under your case will help achieve a stable
in the range you desire.
I still think too-much humidity is less of a problem for flutes than not-enough air circulation. Tenon thread might need to be reduced (cork should, theoretically, adapt), and taking them apart during storage is important (especially with boxwood). But, after all, when we play our flutes, often for hours on end, we suddenly fill them with moisture that undoubtedly rivals the Amazon. Unlike guitars and such, which have glue and other components that might react badly (separate, for eg, or corrode) in extra-high humidity, flutes will simply regain their fullest, hydrated potential; what you want to avoid at that stage, mostly, is mold and fungus, which only really occurs during storage - in other words, don’t store a fully-hydrated flute in dead-air containers. But, overall, I can’t see the flute itself damaged by relatively high-end humidity, or the occasional fluctuations of a drafty house. If you’re dealing with that sort of iffy-humidity, the flute’s probably better off not in a storage box at all, and definitely not in a snug, plastic case. Too humid? Leave it out, disassembled, or in a case that allows for some air exchange. Unless we’re talking about creating long-term, museum-like storage, finding some sort of temperature and humidity controlled constant makes little sense, since you then take the flute out fairly regularly into the real world anyway - rooms that are too warm, wet, dry or air conditioned, whether in your living room, a pub or on brightly lighted stage. And then you play for hours and drive home, the flute in the trunk of your car, etc. Wood is pretty tough - again, it’s the extremes we have to guard against, and a good case and regular playing does most of that for you.
Yes, i was wondering about that as well. My flute spends the majority of time with me in it’s cavallaro zippered case which, in the winter, i keep in a plastic bag. I feel that this is the most stable environment for the flute. I put both the case and the flute in the humidified and vented box when i’m at home and not playing to give them time to breathe so they don’t mold. I like the idea of that box being a relatively stable environment and i don’t want the humidity too high in part because i keep the case in there too. I am willing to believe that i don’t need to keep the flute in the box when at home but i’m not willing to actually do it. I already cracked one headjoint and i don’t want to crack another one.
Always better safe than sorry, I think, particularly if you’ve had a headjoint crack on you. Ultimately, do what feels safest - you won’t hurt your flute being vigilant - it’s that awful “I only left it near the fireplace for ten minutes!” that’ll get you. Any case, you know your flute and its particular environment better than anyone else. FWIW, what you’re doing sounds sensible to me.
Having to babysit several wooden flutes in SoCal where the humidity goes from 60% down to 5% over night! I keep them in plastic tote boxes, during the low humidity days. The boxes are made by Sterilite, and have a loose fitted lid, I just put a sponge in a baggy, it keeps the humidity at 50-60%. I am up in the high desert at the moment, I have my R&R with me, it is happy as can be!
Gordon is right, better safe then sorry! Humidifing is a lot more important then oiling, heat fluctuations are not a problem, as long as the humidity is constant. Terry McGee did some experimenting with heat fluctuation, the mad scientist that he is… 
His findings were that tempriture was not critical. Effect of heat and cold on flutes
Thanks Gordon and Jon. It is nice to hear i am using the same sort of box you are using Jon, a sterilite storage box with a non-airtight lid. To be clear, my problem with temperature fluctuation is that it is causing humidity fluxuations in the box. The classic scenario is that the heat is off in the room for a long period of time and the humidity in the box stabilizes at around 54% or so (i think it was suggested earlier in this thread that cooler is better and i agree, the humidity seems to be more stable when the room is cool). as the room heats up the humidity in the box initially drops, then starts to climb as the sponge water evaporates and if i don’t open the lid some the humidity will get in the 70% range and the flute will start to feel clammy. when the heat drops i have to re-adjust the ventillation again. I have tried just leaving the lid alone and i always seem to wind up with a clammy flute and high humidity. If i leave the lid open a bit the moisture eventually drops below 40%. This really sucks because i wish i could just plop the flute in there and forget about it.
I think i really should just plop the flute in there and forget about it and not sweat the occasional 70%. 
Thanks for the advice,
Bob
Yes, it is better to occasionally go up to 70% then to let it drop below 40%…
I wouldn’t fret much, don’t worry, be happy! 
Cold and dry here, snowing today. It’s been 33/34 inside with the heating off. I have the flutes in their boxes with a piece of damp sponge, then the box is wrapped in a plastic carrier bag. For the old Rudall I have a small digital hygrometer which fits in the box, reading only 38 this morning 
.
I think it is better to put the flute case in a larger plastic case, with a loose top. Over here they make a flat cake box, the flutes case will fit nicely. This gives you more volume of humidified air. For larger boxes you need a larger sponge, which will in most cases not dry out, unless you are dealing with 5% desert humidity, in that case, check the sponge everyday! If you are putting the humidifing sponge in a small closed box, you are not getting air flow.
Be sure to put the wet sponge in a open baggy so it doesn’t do any water damage to the flute case. 38% is to low,you will start getting loose rings, then bits will start falling off!
Remember also that tempriture is directly proportional to humidity, the lower the temp the less moisture can be retained in the air, the higher the temp the more moisture will be retained in the air… This explains why you are getting a lower humidity when the temp changes.
If you have not already done so i would recommend calibrating that hygrometer using the salt method described in this thread:
https://forums.chiffandfipple.com/t/hygrometer-recommendation/85665/1
I did it and found my hygrometer reads 14 percentage points below actual humidity so 38% for me would be about 52% actual.
Thanks for the tips. Came home after work and it was 39. Now it’s reading 41 now. Temp is 20 centigrade. I’ll keep an eye on it. The digital hygrometer is about the size of matchbox and is called TFA 30.5005 Elektronisches Thermo-Hygrometer. Costs around 8-11 euros
Thanks for all your comments. I have been checking the closet I mentioned earlier and it stays around 60% all the time day and night. Its an old antique Flemish furniture. I have opened the lids of the flute boxes by placing a bit of cork between cover and box so boxes are open 1cm. I hope this works. Thanks for all your comments. I noticed that some of you keep the flutes out of their boxes but I find that a bit risky. I noticed in the Olwell documentary that Patrick also keeps his flutes in their boxes in his vault…thanks this was of help to me 