Not that sure about heavy and battery consuming because if we do speak about on this manner then there would be tons of factors that affecting out on battery consumption and just like Zwei said above that you are making use of your mobile phone. Bare in mind that you arent just that opening a single app or browser on this case on which it causes up that drain. Same goes to the factor about on how your phone specs will be affecting it out. If ever you've been that dealing with some images or animations that requires better chipset then if you do have that low spec phone then it will have that kind of feeling of being heavy. Well, as long you do enjoy up then battery consumption will be that least of your concern.