Red hot chilli pepper

Found a wiki page that might help you with this.
http://en.wikipedia.org/wiki/Chili_pepper
Reading the intensity values is eye opening!! HOT!!

Hi UKSlim. I planted my chili plant out in the garden in May and it has been happy there until the recent frosts (I harvested a while ago though). The fruit are small and have quite a kick to them but I did nothing to them and suspect that the heat is down to variety.

Heat is pretty much down to variety. Smaller fruiting varieties tend to be hotter. Hungarian Hotwax, for instance, despite the name, has large fairly mild chillies, and Jalapenos are relatively mild too. We have some I'm going to plant in the New Year that have seeds you have to handle wearing rubber gloves - can't remember the name though, I'll check. They should be ripe by the time you come to visit!!

I have read somewhere that if you give the plant some stress ie dont water it in the greenhouse, and give it extra heat that this will increase the hotness of the chilli. I also understand that the heat comes from the seeds, which we often dont eat.

Try and get plants from a nursery rather than garden centre - you will get more info and more choice. There's the South Devon Chili Farm down this way - i don't know where you are but they might post. I've had some great - and hot ones from them! Try Aji Lemon, bright yellow - devilishly hot - but calms down once its pickled. Or Twilight - a lovely small bushy plant with fruits in red, orange and purple, tiny but very powerful, this is an easy one to overwinter, keep above 5 degrees, and give it a good prune. Good luck!

You cannot change the "heat" of your chillis. The "heat" comes, not from the seeds, but from the "juice", which is called capsaicin. The hotness of the capsaicin varies from variety to variety, and is measured in Scoville Heat Units (SHUs).