Traditional water heaters are the most common type of water heating system in the home. The main benefits of a tank water heater are the low purchase cost, simple installation and large selection of sizes and configurations to choose from.
The primary downside to traditional water heaters is, because the water in the storage tank is almost always being heated, energy is wasted even when a hot water tap isn’t running. However, there are water heater models that have heavily insulated tanks, which greatly reduces standby heat losses, lowering the operating cost. These models have tanks that have a thermal resistance (R-Value) of between R-12 to R-25.
A tank-style gas water heater can be expected to last 8-12 years, while an electric model ususally last a little longer at 10-15 years.
Tankless Water Heaters
The benefits of tankless water heaters include:
Energy Efficient and Environmentally Friendly – Tankless water heaters are environmentally friendly because they are on average 22 percent more energy efficient than conventional water heaters. Conventional hot water heaters heat water all the time while tankless water heaters heat the water only when it’s needed. Since heating water accounts for 30% of the average home’s energy budget the higher efficiency of a tankless gas water heater can save you money on your utility bill.
Endless Flow Of Hot Water – Tankless water heaters heat water directly with out the use of a storage tank. Therefore hot water is supplied on demand.
Long life – In the short run, a tankless system will use less energy, immediately lowering your utility bill. Over the long run, a tankless water heater will last about twice as long as a tank water heater, with most systems having a life expectancy of more than 20 years. They also have easily replaceable parts that can extend their life by many more years. In contrast, conventional tank water heaters typically last 10 to 15 years.
The disadvantages of tankless water heaters include:
Limited Flow Rate – A tankless water heater’s output limits the flow rate of hot water. Therefore problems can arise when hot water is need for more than one use simultaneously. For example a shower is being taken at the same time the dishwasher is being run. In this case the hot water flow will be restricted. To overcome this problem, you can change your lifestyle to limit how much hot water is called for at one time or you can install more than one tankless water heater.
Up-front Costs Are Higher – A tankless heating unit costs more than a tank heater and gas load requirements may require upgrading gas service. Venting restrictions may also limit where the unit can be installed.
Additional Maintenance Requirements – Calcium build up can decrease efficiency, restrict water flow and damage the unit. While not complicated, performing regular maintenance is essential to the achieve the best performance full lifespan of the tankless water heater.