There is a basement which does get a musty smell in the summer (hello humid Michigan summers) but i don’t think that would cause a problem. 

Gets hot and humid there.

Last year (in a flip) we had professionally installed vinyl flooring glued to a perfectly good subfloor & because of a very hot humid summer it was a peeling/lifting in spots nightmare.Definitely not something I would be prepared to experiment with but would be interested in following your progress. 

They provide a backup monitor for temp, humidity, sound and light in the house.

Avila-I installed a light/fanswitch that has a moisture detector on it where the fan will turn on automatically when a certain humidity is reached and it automatically turns off later.

They will monitor and control temperature, you can also monitor humidity.

If you can follow the pipe into the basement or similar, you can verify if it's connected to a gas line.One thing to watch out for on "ventless" gas anything: if you use it a lot, you'll put a lot of water vapor / humidity into the house.  

They theorized a reflection maybe (we have dangerously low humidity right now). 

Have had IAQ tested twice and readings showed higher levels of Co2 (house was closed up prior to testing), as well as slightly elevated humidity and slightly elevated levels of VoCs.

Then again, California almost burned down in 2018, partly thanks to the low humidity.