The best brand ensures quality, efficiency, and good after-sales service. From so many brands here comes the best ones- AO Smith, Havells, Crompton, Bajaj, Racold, V-Guard, and Kenstar.  They offer geysers with a capacity of 10L-35 L. They are available on Amazon and so many online shops. Some of them provide free installation. Even if it is paid they are always better than a calling local plumber.