Understanding the Advantages and Disadvantages of Tankless Water Heaters

We rely on hot water every day for cleaning, washing, showering, and more. This is why a water heater is an essential appliance and they work hard. In the past, the only option was a water heater with a tank where the heated water is stored for on-demand use. But, there are tankless models that heat the water immediately with no need to store the hot water. In this article, we will take a closer look at tankless water heaters and explain the pros and cons when compared to a traditional unit.

4 Tankless Water Heater Pros

A tankless water heater tends to have a longer lifespan of around 20 years. The flow rate is in the 2-5 GPM (gallons per minute) range, but the upfront purchasing costs are typically higher.  A tankless unit would save an average home $100 per year on water heating costs. Let’s take a look at four tankless water heater advantages in more detail. They are:

1.   Hot Water On-Demand

The main advantage of a tankless water heater is that it delivers hot water instantly. Because there is no hot water storage tank, there is no need to worry about the volume of hot water used. As an example: several people could take a hot shower consecutively and the hot water would not run out.

2.   Improved Energy Efficiency

A tankless water has improved energy efficiency when it’s compared to a traditional unit. There is no need to reserve water and maintain that heat to ensure that it can meet on-demand needs. The energy consumption requirements are higher to create hot water instantly. But, the majority of energy used in water heating is the endless cycle of heating and reheating to keep the water hot and ready to use.

This is probably the biggest drawback of a traditional bulky water tank heater. Experts estimate that tankless units have improved energy efficiency in the 24-34% range if the home consumes 41 gallons or less per day. A home that uses 86 gallons or more per day would still have an energy efficiency improvement in the 8-14% range. A home that consumes around 40 gallons of hot water each day would equate to annual energy savings of $80-$100.

3.   Longer Useful Lifespan

A traditional tank water heater has an average expected lifespan of 10 years. Tankless units have a much longer useful lifespan of around 20 years which is double. This ensures that your home has a reliable source of hot water for many years with no need for a premature replacement. This saves money on the cost of a new water heater and the extra installation costs.

4.   Saving Space

There is no getting around the fact that traditional hot water tanks are big. They come in different sizes, but they all have a cylindrical shape which can be hard to accommodate. A standard size water heater tank is 5 feet tall and it has a diameter of 2 feet. This is almost the size of a full size adult and the associated water carrying pipes can be hard to install.

In comparison, a tankless unit has a simple box shape which is 27” tall, 18” wide, and 10” deep. In a smaller home, this saves a significant amount of space even when compared to a small tank unit. A tankless water heater looks sleek and modern and it’s easy to install in a wider variety of locations. A water tank is bulky and harder to accommodate and it will take up far more space in your home.

2 Tankless Water Heater Cons

There are a few tankless water heater disadvantages to consider. They are:

1.   The Higher Upfront Purchasing Cost

A tankless water heater will cost more than a traditional tank unit and for many people, this will be a decisive factor when they are looking for a replacement or upgrade. The average cost of a tankless unit is three times more than a storage tank unit. This places the appliance out of reach for some people and the installation costs tend to be higher too. A good tankless model could start at $500 and the price could rise to $2000 or more for a high quality unit.

The increased installation costs are incurred due to extra wiring to handle the extra load and gas units require a new vent pipe to remove gas fumes. Traditional units have lower installation costs because the technology is simpler and they have been around for much longer. Of course, these extra costs are offset by the energy efficiency improvements and the longer lifespan if the initial costs can be overcome.

2.   Inconsistent Temperatures and Limited Water Flow Rates

One of the main disadvantages of a tankless hot water heater may be related to the volume of hot water that you’re using in your home. The capability of a hot water appliance to meet all your needs is largely determined by the flow rates. Every water using appliance, such as the dishwasher, washer, shower, and more have flow rate requirements. So the flow rate capacity of your water heater is important when you want to run multiple appliances at the same time. To put this into some perspective most on-demand tankless water heaters supply hot water in the 2-5 GPM range. Let’s take a look at an example of this principle in action:

Let’s say that your shower head has a 2 GPM flow rate and a washer that has a 3 GPM flow rate. If your home has a tankless water heater that supplies 5 GPM, it can deal with the shower and washer running at the same time. But, in this scenario, if the shower and washer are in use and then someone turns on the dishwasher, this will limit the supply of hot water. This will lead to inconsistent water temperatures and we all know that sinking feeling when the hot water runs out as we take a shower.

There is an easy workaround, but it requires some advance planning and everyone in the home needs to understand the implications. It’s important to spread out the hot water demands that occur during the day and if you can make adjustments this is not a major issue. Another possibility in a larger home with higher demands for hot water could require a second tankless water heater installation.

If you’re still unsure about a tankless water heater for your home, speak to your plumber.