Top 3 Pros and Cons of a Tankless Water Heater

Tank water heaters have been the traditional source for hot water in most homes for decades. Whether they use gas or electricity, they offer a supply of water that is already heated and ready for use, with average-sized tanks holding 40-50 gallons of water. However, tankless water heaters are becoming more popular due to their on-demand design, energy efficiency and small space needs. Here are the top 3 pros and cons of tankless water heaters for residential use.

Pros of Tankless Water Heaters

  1. Lower energy costs. Tankless water heaters only heat the water on-demand, saving money off energy costs. Unlike tank water heaters that keep water hot 24/7, the tankless water heaters heat water as needed.
  2. Smaller unit. Since there is not a tank, these water heaters are much smaller in size. They can be hung on a wall or even put on the outside wall of a home.
  3. Less risk of water damage. If a water heater tank springs a leak, it can cause extensive water damage in a home. No tank means no risk of a tank leak.

Cons of Tankless Water Heaters

  1. Higher initial cost. Tankless water heaters tend to be higher in initial cost than their tank counterparts, but make up the difference in long-term energy savings.
  2. Slower hot water. Tank water heaters have many gallons of hot water ready to go, while tankless must heat water as needed. This can make it slower to get hot water, but the hot water will not run out like with a tank.
  3. Not well-suited for larger homes. If there are several rooms using hot water at one time in a home, a tankless water heater may have trouble keeping up with the demand. Most tankless water heaters can heat about 3.5 gallons per minute.

If you are looking for a more energy efficient hot water source that will never run out of hot water, tankless may be the way to go for your home. Talk to your local plumber about the options available in tankless water heaters.

Posted on behalf of:
Seagraves Plumbing Sewer & Septic
4980 Plant Atkinson Rd SE
Smyrna, GA 30080
(494) 792-2221

 

Tankless Water Heater Sizing

If you are replacing your storage type water heater with a tankless water heater (also called a demand water heater), you will need to make sure that you choose a water heater large enough to meet your demands.  At the same time, you don’t want to choose one that is unnecessarily large which would waste money and energy.

Storage type water heaters are sized based on their capacity and first hour rating which is the amount of hot water they can deliver in an hour.  Demand water heaters don’t have a tank and are sized based on their flow rate and rise in water temperature.

To choose an appropriately sized demand water heater, you will have to determine the maximum flow rate for all of the appliances and fixtures that you will be using at the same time and how much of an increase in the water temperature you will need.

For example, if you will never have more than one shower going and can remember not to run the dishwasher or clothes washer while you are in the shower, you can choose a smaller unit.  On the other hand, if you have a larger household where two people might be taking showers at the same time, or if you run the dishwater, clothes washer, bathtub or shower at the same time, you will need a larger capacity water heater.

Your plumber can help you determine the flow rate of the various fixtures and appliances in your home.  With that information, you can take into consideration your lifestyle and hot water usage patterns to determine the proper size tankless hot water heater.  The maximum flow rate for a typical tankless water heater is around five gallons per minute.  If your needs are greater than that, consider installing two tankless water heaters to handle the load.

Tankless Water Heater Considerations

If you are building a new home or replacing your existing gas storage water heater, now is a great time to consider switching to a gas tankless water heater.  Unlike a standard storage type water heater that keeps a full tank of water hot 24 hours a day whether it is needed or not, tankless water heaters(also called demand water heaters) only heat water when there is a demand for hot water.

According to EPA estimates, gas tankless water heaters can cut energy usage for water heating by about 30%.  For a family of four, this can amount to about $100 per year.  This may not seem like a huge savings, but considering that tankless water heaters have a much longer life expectancy than storage water heaters, the savings can really add up.

Tankless water heaters can be expected to provide endless hot water for about 20 years.  That’s twice as long as a typical storage water heater.  In the long run, a tankless water heater can pay for itself in energy savings.

There are other advantages too.  Since tankless water heaters heat water as it is needed, you never have to worry about running out of hot water.  In addition, a tankless water heater takes up much less space than a storage type water heater which is a significant advantage when space is at a premium.  Also, with a tankless water heater you don’t have to worry about the tank corroding and flooding your home.

Talk to your plumber about installing an energy efficient  tankless water heater in your home.  The initial cost is higher than a storage water heater, but you can enjoy endless hot water while saving money on energy costs year after year.

Demand Water Heaters

If you are looking for ways to cut your energy costs, consider having demand water heaters (also called tankless water heaters) installed in your home.  A standard tank type water heater wastes energy by keeping water hot 24 hours a day whether it will be needed soon or not.  The energy wasted keeping water hot during period of no demand is called the standby energy loss.

Demand or tankless water heaters eliminate the standby energy loss by only heating water as it is used.  When a faucet is opened or a shower is turned on, the water runs through the heater where it is heated  and then delivered to the tap.  The heating process only takes a few seconds so the supply of hot water is almost instantaneous.  However, just like with a standard tank type water heater, if the tankless water heater is located some distance from the tap it will take a little time for the hot water to make its way there.

The main advantages of tankless water heaters are the elimination of standby energy loss and an endless supply of hot water.  The primary disadvantages are a higher initial cost and a limited flow rate.  The limited flow rate can be a problem if multiple demands for hot water are made at the same time such as running the dishwasher and the shower.  If the demand exceeds the unit’s flow rate, it will not be able to keep up.  One way to deal with this problem is to install multiple demand water heaters that are dedicated to the heavy users of hot water like the washing machine, shower, and dishwasher.

The cost issue becomes less of a concern when you consider that the demand water heater is far more efficient than a storage type water heater.  In the long run, the energy savings will offset the increased initial cost.

Water Heating Energy Savings Tips

According to EPA estimates, up to 25% of the energy used in the typical home is spent on water heating.  You can save money on your energy bills by implementing a few water heating strategies.

Reducing your hot water usage not only saves money on water heating but also on your water bills.  Fix any leaking water fixtures such as sink, tub, and shower faucets as soon as you notice them.  Low flow showerheads are easy for your plumber to install and can save as much as half the hot water used in a typical shower.

Installing a water heater insulation blanket can reduce standby heat loss by up to 45%, especially on older poorly insulated water heaters.  These insulation blankets are readily available at your local home improvement center.  Installation on an electric water heater is something most homeowners can do, but if you have a gas water heater you should have the insulation blanket installed by a professional.

If you have an electric water heater, you may be able to save money by installing a timer that turns your water heater off at night and during the day while you are away from home.  Timers can be especially effective if your utility company charges more for electricity used during peak demand periods.  You can set the timer so that the water heater is turned off during these peak usage periods and heats water during low demand periods when electricity is less expensive.

Finally, when it comes time to replace your water heater, consider installing a tankless water heater and be sure to look for a water heater with the ENERGY STAR label.  You will save energy throughout the service life of the water heater.

Disadvantages of Electric Tankless Water Heaters

The allure of unlimited hot water and the thought of saving energy on water heating costs have led many homeowners to consider installing a tankless water heater to replace their conventional storage type water heater.  Tankless water heaters can be a great choice for many applications, but they are not a “no-brainer” type of purchase especially if you are considering an electric tankless water heater.  There are some disadvantages to consider before you take the plunge on a tankless water heater installation.

A storage type water heater wastes energy by continuously keeping a tank of water hot, even when there is no demand for hot water.  Tankless water heaters (also called “on-demand” water heaters) save energy by only heating water when it is needed.  Since they heat water on demand, they can continuously supply hot water and will not run out like a storage type water heater.

However, if you are considering an electric tankless water heater, you may not see any cost savings on your energy bill and may even spend more on electric energy for water heating.  The reason is that electric tankless water heaters use a lot of electricity when hot water is needed which is often during peak usage periods such as during the day when people are bathing or doing laundry.

Some utility companies charge higher rates for electricity usage during high demand periods.  You may end up using less electricity with the tankless water heater, but paying higher rates for electricity which would wipe out any energy cost savings.

In addition, because they use large amounts of electricity when they are heating water, installing an electric tankless water heater may require upgrading the electrical wiring in your home.  Your plumbing professional can help you decide if an electric tankless water heater is good choice for your home.

Endless Hot Water

With fall here, and winter around the corner, you want plenty of hot water for those early morning showers or late night baths.  The colder it is, the harder it is to handle cold water and there is nothing worse than having a shower turn cold on you on a cold day outside.

The best solution to this problem is having endless hot water, but how can you do this without spending a fortune?  The answer really is quite simple:  the best bet is an endless (also called an ‘on demand’ or ‘tankless’) hot water system.  Endless hot water systems actually save energy and water by providing on demand hot water when needed.

Endless hot water systems generally provide hot water around 5 gallons per minute.  Gas fired tankless heaters tend to produce slightly higher amounts, and electric tankless heaters slightly lower amounts.  When you are shopping for your tankless system, consider the number of outlets (sinks, showers, tubs, washers and dishwashers) that may require hot water.  Then, seriously consider what the usage is.  How often are more than one item used at the same time?  Make sure to purchase the tankless system that is sized realistically for your home.

As the temperatures cooler, investing in a tankless water heater may be a great choice for you and your family.  Having plenty of hot water for everyone at home will always bring a smile to faces.  The energy savings from a tankless heater will bring a smile to your face, too.  On the average, tankless water heaters are 20% more energy efficient than traditional water heaters.  This helps lower your energy costs and allows you to be more energy friendly while still enjoying your hot showers!