If your demand for hot water is not being met there are a few options that you can consider. Most of the time people will jump to the possibility of a tankless water heater. A tankless water heater works well for many applications but for most homeowners it is more of an investment that it’s worth.
Another option that people often ask about when they are not getting enough hot water is to go with a larger unit such as a 75 or 80 gallon water heater. There are several different types of large capacity units, most of them are commercial water heaters. Some commercial water heaters can exceed over $3000 just for the tank alone. However for residential applications you can use a Bradford White 75 gallon water heater which will cost a little over $1200.
The third option for increasing your hot water supply is to install a second water heater. When installing two water heaters there are two methods that are commonly used are the Series installation and Parallel Installation. For most cases we will usually recommend installing the water heaters in series. This is going to be the most efficient way to install the units and it’s also easier to install.
Series vs Parallel Water Heaters
This is a debatable issue even among professional plumbers. My personal opinion is that they both have their advantage for certain applications. The biggest advantage for many plumbers is that a series application is a little easier to install. If you run your water heaters in parallel then it has to be perfectly symmetrical. Water will always take the path of least resistance. If you don’t setup your parallel series properly, you will have the majority of your water running through only one of your hot water heaters. This will result in a poor performance in both output and energy consumption.
The main advantage to installing a water heater in series application is in a situation where there is not a constant high demand for hot water. When we install two water heaters inside of a residence we will usually set the first water heater on the lowest setting and the second water heater to run a little hotter. By having the first water heater on a lower setting you will be able to save on energy. Maybe you only need the extra hot water when you have family visiting for a period of time. If this is the case you can actually turn off your first water heater when you don’t need the additional hot water.
For most commercial or multi-family applications where you constantly need a supply of hot water it may be better to install the water heaters in parallel. This installation method will provide a little more hot water in terms of output but you will likely increase your energy consumption. Both water heater will need to be set to operating temperature. If you install multiple water heaters in series and add the appropriate check valves you can shut down one of the water heaters by closing off the ball valves.