if you can connect some jumper wires from point to point then I would suggest looking at using a arduino micro controller. I know that it looks complicated but with some assistance from people with the same interests we can help you assemble and write code to control anything,
arduino uno clone $5
dht22 temp and humidity sensor $7
dual relay $3
7 seg led driver plus leds $2
premade cables $6
the great thing with arduino is skys the limit
If you want a few more temp sensors ($2 each) that's no problem, If you want a lcd screen instead of 7 segment leds then that's only a few bucks more.