I had a LABRADOR , wish to have a ST Bernard?

Some years ago i had a Labrador , as a dog lover i loved labs very much coz they are lovely cute and obedient , but the problem is i'm native of south india ( kerala) here the climate is too hot he is go on drinking water always , we don't put dogs inside the home but there is a good big cage outside with a fan installed , ma lab face many diseases like ear infection eye problems and walking problems vet had treated even many other disease affected him at the end , so i don't like to have a lab any more so and next plan to have St bernard how about this dog is compared with Labrador , are they similar in behaviour ??