There are several types of water tanks depending on the fuel they use. Each type has its own pros and cons:
Electric water heater
These tanks use replaceable electric heating elements to heat up water. Their biggest advantage is their price, which is significantly lower compared to hybrid or gas heaters. Plus, some commercially available electric tanks are highly energy efficient.
Gas water heater
These tanks use gas burners to heat water, which is why they require adequate air circulation around them at all times. Plus, you need to ensure that there are no flammable or combustible materials in the vicinity of the heater. While these tanks are more expensive than their electric counterparts, they are also more energy-efficient, which can save you money in the long run.
Hybrid or heat pump heaters
These appliances take energy from the air and use it to heat up water. Even though these tanks are more expensive than units that utilize other energy sources, they are more energy-efficient. Plus, they generally have a larger capacity than other heaters.