yes, even when i'm at home i do that coz the tiger bag has a layer of insulation in the bag. Maybe u put into your bag then see if it works better?i still have not give up lol. use it today again and see how. if really cannot then bo bian.. i bought from amazon .. think cannot change.. it can keep my boiling water very warm inside even after 6hrs but then my cereal and porridge so easily cold dont know why...
oh do you keep the containers into the bag when keeping warm? cos i didnt. i only put on my kitchen top