First time Hatcher here so please keep this in mind. This is what I have learned since I started this little adventure. Others may have had totally different experiences.
I have the LG still air. I have had temp spikes to 108 and as low as 96 degrees.
You really have to watch the temp on these units. Especially the first few days. If you haven't added eggs already, you may want to run it empty with water in the wells and plugs out until it stabilizes. The turner knob is
very sensitive. Only a hair of a twist will increase or decrease temps
substantially. (Ask me how I know
I've also seen ways to modify this by adding a bigger knob on other posts.
Ive heard the addition of a circulating fan can increase your hatch rates by stabilizing air temps. .The prices Ive seen on these range from 28.00 to 40.00 plus.
I have one plug in and one out and move the plug over part of the ventilation hole to manage small fluctuations in temp. This may also decrease humidity so it can be a real challenge or not, depending on which school of thought you subscribe to with incubating humidity. I heard both plugs need to be out at lockdown, but again, there are several opinions about this so you will need to draw your own conclusions.
Every time you open this Bator you will have a temp decrease but it may be delayed and may come up slowly or really fast so remember that before you touch that knob. Every time I have moved the little knob I've had to CLOSELY monitor temps for 6 hours afterwards until temps have become stable. This alone is a good reason to get the egg turner.
Get a hygrometer if you don't have one. It is sooo worth the 6 to 10 dollars.
I am on day 9 and am curious myself about how to manage humidity on these units, as I have never gotten it over 50% and know I will have to master this by hatch time.
All of this said, many people have had successful hatches with these units and excellent results..
Best of luck to you.
Keep us posted.