Storage Water Heater Vs Tankless Water Heater: Which is the Best?

Storage Water Heater Vs Tankless Water Heater

According to ‘Edward Allen and Rob Thallon’ (Author of book called Fundamentals of Residential Construction), Water heater is a device that heats the water for domestic consumption. Physically looking, there is no difference between a water heater and a geyser as such. The word ‘geyser’ is used colloquially in many countries for water heater when it is used for domestic purpose.

Hot water serves several domestic purposes. It is required in house for cooking, bathing, cleaning, etc. For that purpose, water heaters are installed and are connected to various appliances. In order to supply the hot water through the water heater, generally Copper pipes, Polybutylene (PB) pipes, Chlorinated Polyvinyl Chloride (CPVC or PVC) pipes, Random Polypropylene (PP-R) pipes, Cross linked Polyethylene (PEX) pipes are used in hot water system.

Water heaters operate on different fuels such as electricity, gas, oil and solid fuel i.e. wood and biomass. There are water heaters which also operate on solar energy. Depending upon the fuel on which it operates, the water heater is classified accordingly as gas water heater, electric water heater and solar water heater. These water heaters are available in two types – storage and tankless water heater.

Let us see how Storage Water Heaters and Tankless Water Heaters differ from each other:

Storage Water Heater Vs Tankless Water Heater

Mentioned here are the dissimilarities between the storage water heater and tankless water heater/instant hot water heater.

01. Definition

Storage Water Heater

A storage water heater is a device that contains a storage tank to maximize heating capacity and provide instantaneous delivery of hot water.

Storage Water Heater

 

Tankless Water Heater

Tankless water heater is a device that heats the water instantaneously and simultaneously as it is being used.

Tankless Water Heater

 

02. Synonyms

Storage Water Heater

Storage water Heater is also called Storage tank water Heater.

Tankless Water Heater

Tankless water heater is also called instant water heater or demand type water heater.

03. How Water Heater Work?

Storage Water Heater

  • In Storage Water Heater, water is first filled in the tank and later heated. It requires time to heat the water i.e. hot water is not instantly available. If it is an electric heater, you will have to switch on before you use it.
  • When water gets heated up to a specific temperature, the thermostat will sense the water temperature and further heating of water shall stop automatically.
  • Only the quantity of water that the tank can accommodate is heated, i.e., the quantity of hot water available would depend on the capacity of the heater.
  • Once the hot water in the tank is used, the tank gets refilled, and water is heated again in it. This process requires time.

Tankless Water Heater

  • In Tankless Water Heater, the incoming cold water enters through the inlet, passes through a heat exchanger in which it gets heated, and hot water is instantly available at the outlet.
  • The switch has to be turned off to stop the heating of incoming water.
  • Once the hot water is used, the incoming water is heated instantly, and thus, hot water is available continuously.

04. Components of Hot Water Heaters

Storage Water Heater

  • It consists of thermally insulated storage tank, thermostats (temperature sensitive device), pipes and heating elements (either electric heating or gas burners).
Storage water Heater Elements

Tankless Water Heater

  • It consists of a switch, small pressure vessel with a heat exchanger and a pilot lamp (a lamp that lights up when circuit is closed). The heater is to be switched off immediately after use, hence no thermostat is required.
Tankless Water Heater Elements

05. Carbon Dioxide (CO2) Emission of water Heaters

Storage Water Heater

  • CO2 emission is more.

Tankless Water Heater

  • CO2 emission is less.

06. Efficiency

Storage Water Heater

  • As compared toTankless water heater, efficiency of storage water heater is less.

Tankless Water Heater

  • Efficiency of tankless water heater is better compared to the storage water heater.

07. Life of Hot Water Heaters

Storage Water Heater

  • Life span is 10 to 12 years.

Tankless Water Heater

  • Life span is about 20 years.

08. Advantages

Storage Water Heater

  • Suitable for large establishments.
  • They are available in variety of sizes.
  • The flow (quantity of water coming from the tap) and the velocity (the speed at which water comes) is acceptable. Hence, it is better for use and provides adequate flow.
  • If there is more than one bathroom in a house, it reduces capital costs.

Tankless Water Heater

  • Continuous hot water flow is available.
  • It does not generate standby energy (heat) losses.
  • Water quality is not affected because water is not stored.
  • Water is not contamination as it is not stored in the heater.
  • Suitable for small establishments.
  • Heat loss is less due to short pipe length for the conveyance of hot water.

09. Disadvantages

Storage Water Heater

  • Continuous hot water flow is not available.
  • Hot water stored in the tank continually loses heat.
  • These heaters affect the quality of water due to the storage of water in tanks.
  • Hot water flow is available as soon as the hot water tap is turned on. Of course, this is possible after the initial heating, which may take time between 10 to 20 minutes depending upon its capacity.
  • If the temperature of hot water reduces below 60° C, water stored in the tank gets contaminated due to the breeding of bacteria.
  • More pipelines causes heat loss during conveyance of hot water from the storage water heater to the fixture.

Tankless Water Heater

  • Exchanger first builds up the temperature, and later the hot water comes out. This process may take a couple of minutes or more.
  • The flow and velocity both are comparatively lesser than the storage water heater and hence it is not suitable where enormous quantity of hot water is required.
  • It is not suitable as water flow is not adequate.
  • A gas geyser befits more than one bathroom, i.e. there is no need of separate geyser in each bathroom. Whereas in case of electric geyser, separate electric geyser is required for each bathroom.

10. Cost of Water Heaters

Storage Water Heater

  • Capital cost i.e. initial cost is more.

Tankless Water Heater

  • Capital cost is less but more power is used in case of electric geyser. Gas geysers are cheaper than electric geysers.

11. Fuels for Water Heaters

Storage Water Heater

  • Electricity
  • Gas
  • Solid Fuel (wood, coal, biomass, charcoal)
  • Sunlight – (Solar Energy)

Tankless Water Heater

  • Electricity
  • Gas

12. Purchasing Guide for Water Heaters

Storage Water Heater

  • These heaters are recommended as per the capacity i.e. minimum amount (gallons/liters) of hot water a geyser can deliver. Eg: A 30 gallon storage heater will store and yield 30 gallons (114 L) of water. One may choose the geyser depending upon the family size. Make choice of heater accordingly.
Storage Capacity Recommendations
  • First Hour Rating (FHR) is taken into consideration. It is the number of gallons of hot water the heater can supply per hour (starting with a tank full of hot water). More FHR means more quantity of hot water available.
  • Always choose more efficient (more stars) water heater.

Tankless Water Heater

  • Theses heaters are recommended on the basis of quantity of water required at fixtures. Normally this is the water quantity required for various domestic purposes.
Average Flow at Fixtures
  • Add the GPM of fixtures in use and make the choice of heater accordingly.

For Example: If a user has a shower, washing machine and a sink, he should prefer (3.0+2.0+1.5 = 6.5GPM) capacity water heater.

  • Gallons per Minute rating (GPM) i.e. quantity of water flow available per minute is taken into consideration.
  • Eg: A 6.5 GPM water heater will deliver 6.5 gallons (25L or 1 bucket) water in 1 minute.
  • Always choose more efficient (more stars) water heater.

Summing up, Now that you have already gone through the comparison of storage water heater and tankless water heater, you should consider your needs and then go for the one that is best for you. What is furthermore essential is; you also need to consider your budget while making the selection of water heater.

Well, we would still recommend you to go ahead with the tankless water heater. It is the best choice as it is energy saving, and its efficiency is better than the storage water heater. Apart from these good features, the heater also maintains the quality of water. The storage water heater would be a perfect choice if the quantity of hot water required is more and sufficient space is available at home.

Must Read:

How to Choose the Best Tankless Water Heater for your Home?
Best Water Heater-How to Choose as per the Need of Your Home?
Electric vs Gas vs Solar Water Heater

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