Pros and Cons of Tankless Water Heaters

Have you thought about a tankless water heater for your home?  There are many benefits long-term.  We use them in most of our construction projects.

A tankless water heater uses 30 to 50 percent less energy, saving a typical family about $100 or more per year, depending on water usage. Tankless units (also called “on demand” units) heat water only when you turn on the faucet. They usually operate on natural gas or propane. The main advantage is that they eliminate the extra cost of keeping 40 to 50 gallons of water hot in a storage tank, so you waste less energy. They also offer a continuous supply of hot water, which is ideal for filling a big hot tub or a whirlpool. They provide very clean water – you avoid using water that has been stored in a tank with accumulated rust and scale.

Tankless are more compact than a standard water heater and mount on a wall. Traditional water heaters with 40 to 60 gallon capacity are generally around 60″ tall and 24″ wide. That bulky metal tank can take up real estate in a home where space is at a premium. A tankless water heater, in comparison, might be the size of a large computer, perhaps 20″ wide by 28″ tall and just 10″ deep.

Their life span is longer. While a typical tank water heater is supposed to last 10 to 13 years, tankless water heaters are estimated to last up to 20 years. If you’re planning to stay in your home for a while, that’s a hefty replacement cost you are saving.

What are the disadvantages?

The primary disadvantage is the upfront cost. The smaller units that you often see won’t produce enough hot water to serve most households. They will only serve one faucet at a time—a problem if you want to shower while the dishwasher is running. A tankless water heater has a throughput limit, able to supply a few gallons of hot water at all times but also at a time. So if you have a large family and everyone’s taking a shower, doing the laundry and dishes at the same time, a tankless water heater might not be up to the task or suitable for your family’s particular needs.  Larger units that can handle the demand of a whole family are more expensive, or sometimes you need to buy two.

Because tankless units have high-powered burners, they also have special venting requirements (a dedicated, sealed vent system, which requires professional installation). Natural gas burners often need a larger diameter gas pipe, which can add to the initial installation cost.

The bottom line is that you will make up for the extra cost of a tankless water heater since  you will use less energy over time, but having to put up that money up front is not always an option for everyone. When you are pricing a unit, be sure to get an estimate or firm bid on installation costs. This is not a do-it yourself project unless you have pro-level skills. Talk to your contractor or you can find tankless water heaters at many home centers and plumbing specialty stores.