temp control in an unstable (temp) apt

[Humble_Stoner]

Hey everyone.
I'm growing some Dinafem Roadrunner in a growcab (20x33x50"). right now they are seedlings with just 1 26w 6700k cfl on them, and a heater to keep them at 70f.
i'm planning on getting a 250w hps soon but i want to know how i should go about dealing with temp control first considering my apartment temperature fluctuates with the weather due to no central air/heat.
i'm on a very limited budget, so i might have to get a little creative.

is there a cheap thermostat that i can buy and somehow connect to my lights and or a fan?

any other ideas?

help is very much appreciated from my online teachers and peers.
thanks

 

[geopolitical]

If you have a heater that's working now I would go for the 250w HPS. There may be some very brief times you won't be able to use it due to heat (I'm guessing you fry in august?), but you'll find that the extra output compared to a 26w bulb will more than make up for it.

 

[Sam the Caveman]

don't know what country your in, but you can find used window air conditioners for $50 on craigslist.

There are attic fan thermostats that can be had for about ~$30.

I run a 400w cmh in a bedroom with no supplimental a/c and the temps stay in check, but I'm in a warm climate. we don't need the heat much down here.