A comparison between electric, solar and gas water heaters

   
The electric water heater
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The solar water heater
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The gas water heater
Historically, the electric water heater (EWH) is probably the first of the three water heating technologies to have found its way to Mauritius. The EWH was very popular as recently as 5 years ago. However, unfortunate electrocution cases that occur from time to time and the introduction of the gas water heater (GWH) meant that the public, in its majority, rapidly abandoned the EWH. What follows are the advantages and disadvantages of the EWH compared to the gas and solar water heaters.

  The solar water heater (SWH) has been present in Mauritius for a fairly long time now. It is only recently, however, that it is gaining popularity thanks largely to high prices of electricity, gas, and environmental concerns. The advantages and disadvantages of SWHs are given next.   The gas water heater (GWH) is, today, the most common means of heating water for baths. The GWH is inexpensive, quite safe (compared to the EWH, in particular), and has good reliability. The advantages and disadvantages of the GWH are given below.
Advantages        
The EWH is much less costly than the solar water heater (SWH).
The EWH provides hot water at any time of the day and however the weather is (as long as there is electricity, of course).
 
  • It costs absolutely nothing to heat water since freely available sun rays are used for that purpose.
  • Since the heating costs nothing, the warm water may readily be used for such purposes as dishwashing; in addition to baths.
  • Since no fossil fuels are burnt, this translates into zero greenhouse gas emissions. Therefore, using solar water heaters helps combat global warming as well as other kinds of pollution problems.
  • Because the SWH has essentially no moving parts, it will not break down easily and can last for 10 – 30 years.
  • Therefore, the up front cost of the SWH is more than recovered over its lifetime.
 
  1. The main advantage of the GWH is its low initial cost. The prices start as low as Rs 2000.
  2. Hot water is available at any time of the day and whatever the weather is.
Disadvantages        
Since electricity and water make a potentially lethal mix, low quality EWHs or faulty electrical installations may represent a risk of electrocution.
Over the lifetime of the electric heater, the cost of electricity used will amount to sizable proportions. This is especially true in view of recent electricity price hikes.
The use of electric water heaters contributes to the emission of greenhouse gases as well as plain air pollution.
Unless there is a water tank already installed; the EWH will provide no hot water during cuts. This is not the case with solar water heaters which have built-in tanks to store hot water.
The EWH is more expensive than the GWH. Prices start at around Rs 5000.
 
  • The up-front cost of the SWH is quite high.
  • If sufficient sunlight is not available for extended periods of time (e.g. during cyclones, torrential rains etc.), the water will not heat up adequately. However, new SWH models usually come with an auxiliary electric heater that can be used to heat the water during very cloudy days.
  • If hot water is not drawn from the SWH for some time, the water in the pipe from the SWH to the tap will lose its heat. Therefore, when the tap is opened, some cold water will flow before hot one arrives. The amount of cold water that will flow will depend on the length of the connecting pipe. This is, however, a minor issue compared to the benefits the SWH brings.
 
  • Even though the GWH is, apparently, comparatively safer than the EWH; there still are risks associated with its use. For example, there have been a number of fatalities due to gas explosions and carbon monoxide suffocation. These unfortunate accidents may have been caused by negligence or poor quality of the water heaters.
  • The gas water heater user is totally at the mercy of any rise in the price of gas.
  • The use of GWHs is environmentally harmful since it releases carbon dioxide gas.