Will this heat mat make my pedes too hot?

I'm in the UK and my house can get very cold so I thought having heat mats for my girls would help.

This heat mat is 12W and will be put on the end of their tanks, will it be too hot for them? Or will they be okay?

I'm in the UK and my house can get very cold so I thought having heat mats for my girls would help.

This heat mat is 12W and will be put on the end of their tanks, will it be too hot for them? Or will they be okay?