Tankless Water Heater vs. Storage Tank Water Heater

Water heating is a process of heat transfer to water from an energy source after the energy has been converted.

12:31 20 February 2020

Hot water is needed in a domestic setting for different reasons, like; cleaning, bathing, cooking, space heating, laundry, etc. While in Industrial settings, hot water and steam are used for a lot more reasons.

Traditionally, water is heated in kettles or cauldrons, made of metals like aluminum or copper. These vessels are somewhat archaic as they do not continuously heat water. Due to the advancements of technology, there are now appliances that supply hot water continually. They are known as water heaters. These heaters can be used domestically or industrially, their energy source can be gas or electric, and they can be tankless or possess a storage tank.

Since the invention of the tankless water heaters, there has been a debate about the better option. Both types of heaters have their advantages and disadvantages, and to settle the tankless water heater vs. storage tank water heater debate, a look into their pros and cons is necessary.

Storage Tank water heaters

The standard method for heating water is with the storage tank units; they are quite useful and have a low installation cost. They store hot water, about 20-80 gallons, for use on demand. The way it works is that cold water is pumped into the tank from the bottom, where it is heated to replace the hot water that has been collected and used.

When the temperature of the water stored in the tank is less than a certain amount, the heating mechanism is triggered, turning on the electric element or the gas burner which heats the water till its temperature reaches the upper limit. In this way, it is ensured that the water in the tank is always heated.

Tank-type water heaters have an estimated lifespan of 8 to 12 years. Installing one costs between $500 and $800. The operation cost of each tank-type unit depends on its energy source, i.e., gas or electric heating option. Electric powered water heaters are often more expensive to maintain than their gas counterparts. This is because of storage tank water heaters powered by gas use about 50% less energy. Maintenance of tank-type water heaters needs to be done by a qualified professional at least two (2) times per year, and this is necessary to enable the tank function properly for its entire lifespan. A more detailed review and analysis on water heater installation cost can be found in this post.

Pros

• Tank-type units are cheaper to purchase.
  
  
• Installing storage tank water heaters is relatively inexpensive.
  
  
• This type of water heater has a higher rate of hot water production, i.e., gallons per minute.
  
  

Cons

• Significant standby heat loss reduces the energy efficiency of these units.
  
  
• Not enough hot water available at a time because the water contained in the tank is limited.
  
  
• Sediment buildup is quite high with storage tank heaters.
  
  
• Risk of leaking tank and other associated hazards like slips and falls.
  
  
• Storage tank heaters are quite bulky and detract from the aesthetics of a room.
  
  

Tankless Water heater

Tankless water heaters do not require a storage tank; they heat water as it flows through the unit instead of using a tank. In this unit, the cold water runs through the pipes to a point where a gas burner or an electric element will up heat the water to a specific temperature. The heated water then flows through the piping to wherever it is in demand. Due to this, tankless water heaters are quite small and unobtrusive. This helps in saving space and makes placement quite flexible.

Tankless water heaters have an average lifespan of about twenty (20) years and an installation cost of between $2,000 and $4,000. This is based on the type of model and the additional renovations to make this tankless unit operational. Cost of installation for electric tankless heaters can be next to nothing because some houses are already wired well enough to handle an electric tankless unit. Costs of running tankless water heaters depend on the type of energy source used; electric tankless heaters or tankless gas heaters. However, these are more inexpensive than storage tank units. 

The energy efficiency of tankless heaters is higher than with tank-type water heaters. This is because much less energy is used in storing hot water. According to Verner Ellen, home improvement expert and founder of Verellen Home Comfort, tankless water heaters require less maintenance than their storage tank counterparts, and these are usually restricted to changing the filters. With some models, especially like those recommended in this list, homeowners can do this maintenance themselves, so they are also economically friendly.

Pros

• Tankless water heaters are up to 34% more energy efficient than Tank-type water heaters.
  
  
• By design, tankless water heaters can supply an unlimited amount of hot water.
  
  
• With tankless units, issues like leaking tanks, unsightly tanks, noise, sediments, etc. are eliminated.
  
  
• These tankers are much smaller in size and so increase placement options.
  
  

Cons

• Due to the small number of gallons of water, a tankless heater can heat up in a minute (2-5 GPM); the flow of hot water is limited.
  
  
• The energy savings made by using tankless water heaters do not always cover the initial cost of purchase and installation.
  
  

Based on the tankless water heater vs. storage tank water heater debate; storage tank water heaters are well regarded by users because they have been the norm for decades, and this is an excellent advantage because people are familiar with it.

The installation costs of tank-type heaters are much less than those of the tankless water heaters, but the tank-type units have a lifespan that is half of what is obtainable from the tankless units. If you have a fixed income, then a storage tank water heater will be ideal for you.

In conclusion, while a traditional storage tank water heater is still an acceptable heating appliance, it is quite obvious that there is a better performing improvement available especially if one is looking for a replacement or a new unit.