Hey thats a good point i have never realy considerd the heat patterns before but i always thought it was only realy an issue if you were growing in a roof conversion or something my grow room is at the bottom of 2 floors so i think they would have a hard time seeing it. As for the laws regarding cultivation in the UK its very much dependant on if they can prove your selling it or your just growing it for personal use. Its unlikely you would do jail time for anything less than a trully major operation and even then only if they can prove you are selling it. If they can link money that your not supposed to have to your weed thats when they start to get serious and the max penalty is still 15 years in the UK..