Most of the water heaters that are sold today are of the Atmospheric or conventional variety. This type of water heater is a gas burning appliance that vents through a flue or chimney. Next to a standard electric water heater, an Atmospheric vent water heater is the least expensive type that can be purchased.
The efficiency standards for water heaters has been increasing over the last 10 years. In 2015, the requirements for tanks under 55 gallons will be raised from .58 to .62 which means the types of Atmospheric water heaters you can buy will be very limited. Starting next year Atmospheric water heaters will require an extra 2″ on insulation increasing the diameter of the water heater.
When an Atmospheric water heater just won’t cut it for efficiency requirements or space limitations next step is a powered flue damper water heater.
A flue damper helps conserve energy by blocking off the flue when the water heater shuts off. This type of water heater will require an electrician to run 110 power in order for the water heater to operate. This type of water heater will not work if the electricity is not on.