Warming and Cooling the Room

Alright, I'm starting up my first grow and I'm being relatively serious about it on a small scale. It's a box going to be 6ft x 23 inch x 23 inch for personal grow.
But where I live gets 17C degrees cooler than where the plants want to be during the winter months and our houses are poorly insulated. That's because during the summer months we exceed 40C degrees. I need a way to cool and warm my room that can follow a thermostat. I want to keep in that 24 degrees celcius sweet spot.
Thanks in advance.

Just get a good fan that exchanges the air at least every five minutes. Cooler temps r not a horrible thing. Just make sure to not let them get too hot. In nature temps go up and down. It's ok.

I disagree with MMJ. You do need to control your temps Haxzorr. For example... If it is too cold the plants can refuse to go into flower. Yes, temps go up and down in nature, but cannabis has a temperature range it likes to grow in.

Yeah I agree with PhatJay. It's okay for the temperatures to go up and down. But with the amount of effort I've put into this I don't want to grow schwagg bud. Humidity goes up and down in nature but the plants still prefer a solid range don't they?
Anyone got some viable answers?

Get an AC unit. Problem solved

Re-read the question man. The box is 23inches at it's widest. There is no space to mount an aircon of relatively any size. Let alone a temperature precise air conditioner. For certain there will be SOMETHING on the market that would suit my needs, but not within my budget.
Anyone?

I guess I'm throwed off by the Celsius shit. All I'm saying is that my plants stay at 75 with the lights on and it might drop to 62 at night. This has not had an effect on my grows. Only time I had problems was when my fan broke and the temps got too high. I tried to finish the grow without another one and suffered. Once I got a new one everything has been fine since. So I guess we can agree to disagree. Although 17 degrees Celsius is probably a lot. I read fast and I was thinking F.