I found this wireless indoor out door thermometer in the listing for Lowe's pre Black Friday sale. It was under 10 bucks and works fine. Jack(https://busconversionmagazine.com/forum/proxy.php?request=http%3A%2F%2Fi1075.photobucket.com%2Falbums%2Fw435%2Foltrunt%2FIMG_20151118_210128_zpsdspac8rq.jpg&hash=767dd3d41160f3a91c27bf4ec28c40dfb0d96b2b)
i actually have a similar device with 3 transmitters i keep two in my baggage/utility bays and one hanging in a tree :)
I have 1 of those a different model with a ,snooze,alarm,clock, light, 4 sensors and humidity reader I like it but mine eats the AA batteries lol and I paid a lot more than 10 bucks
I got 1 of those in my bus saw it say 110 outside 56 inside lol
Wow! I thought my over the road A/C was good but that is truly remarkable! :D :D :D
I have 3 roof airs and 2 basement units :P
You're not truly camping until you are wearing two sweaters and a turtleneck inside your bus in July in Tennessee... ;D
I have one of those inside/outside dealies too, I like it a lot.
Brian
In the past I had one in the engine compartment and one in the generator bay, worked great,