Hot water tanks ensure that homeowners have hot water on demand, whether they are washing pots and pans or taking a relaxing bath. Residential hot water tanks usually hold 40 to 60 gallons of water; commercial tanks will have increased capacity. The size of the tank needed depends on the size of the house or building, the amount of hot water typically used and the tank's recovery rate.
Cold water is fed into the interior of the tank, where the heating mechanism raises it to the appropriate temperature. The water rises within the tank as it heats, ensuring that the quantity of water released from the tank is always the hottest water available within the tank.
As homeowners consider purchasing new hot water tanks, they should start by considering the capacity of their old tank. If the old tank failed to keep up with the home's hot water demand, then homeowners should consider purchasing a larger tank. Also, if homeowners expect their family to grow, a larger tank may be a good idea.
Recovery rate is also an important consideration. The First Hour Rating (FHR) on the Energy Guide sticker will show the amount of water that the tank can heat in one hour. A one or two-person household may choose a tank with only a 30 to 40 gallon FHR, while a large family of five or more people may purchase a 50 to 80 gallon model. Also, a gas unit will typically have a higher FHR than an electric unit, so gas units can do the same job with a smaller tank.