By Karen Thuranira

What is a Solar Water Heater?

A solar water heater is a device that captures sunlight to heat water.

Water heating accounts for a substantial portion of energy use in residential, commercial and institutional premises. Solar water heating systems which use the sun’s energy to heat water rather than electricity, gas or fossil fuels can efficiently meet up to 60% of the hot water demand.

How does a solar water heater work?

1. Light is absorbed by solar collector – The solar water heater absorbs light by means of a collector placed on the roof and converts it into heat.

2. Heat transferred to water tank – The heat is then passed to a water tank by means of a circulating pump. This exchange is triggered by the thermal regulator, but exclusively when the collector is hotter than the water in the tank. This not only prevents the circulating pumps from needlessly using electricity but conversely, also avoids overheating.

3. Insufficient sunlight? Back-up heating system  – When there is insufficient sunlight, the water is preheated and a back-up system takes over to bring the water to the required temperature. This system can therefore be used at a constant temperature throughout the year.

Monetary savings from installing a solar water heating system will depend on a variety of factors including;

  • Climate
  • Hot water demand
  • Electricity cost
  • Water temperature required and
  • System efficiency.

On average however, a solar water heating system can realize a saving in electricity bills of 50-80%.

The expected life span of a SWH system is approximately 40 years and therefore a consumer can look forward to at least 30 years of “free-energy”

Here below are some of the key benefits offered by Solar Water Heating Systems. They include;

  • Development and utilization of indigenous energy resources – solar energy is the principle source of energy and the most indigenous source ever used by man-kind
  • Provision of hot water throughout the year- solar resource is relatively available all year round especially in Kenya.
  • Reduced energy bills – solar resource is free and one only needs to purchase the components
  • Reduced pressure on expensively-run power plants – resulting from increased peak demand for grid electricity partly used to heat water.
  • Reduction of carbon emission footprints – solar energy is free of carbon emissions and we get hot water which is also free of the same. By replacing or substituting the fuels used to heat water with solar energy, the amounts of carbon emissions are directly or indirectly eliminated and/or reduced.
  • Enhanced national energy security- through diversification of energy supply options and reduction in the over-reliance on petroleum and biomass use
  • Increased employment, capacity building and income generation resulting from the expanded solar water heating industry
  • Source of national revenue–SWHs provides an opportunity for the government to trade on Carbon Credits with emissions-ridden nations. 

Below are a few situations that would be ideal for installing Solar Water Heating Systems. They include:

  • Buildings that use hot water 7 days in a week
  • Buildings that are open all 12 months of the year
  • High cost of avoided fuel (electricity, oil)
  • Available roof or ground area to mount the collectors (unshaded)
  • Large hot water usage to justify installation of solar thermal system
  • Temperature requirements that are within the range of solar thermal systems
  • Uniform load; hot water used at all times of the day or more at noon/afternoon

Examples include: hospitals; laundries; apartments/hotels; military bases; prisons; restaurants, etc.

Recent studies show that residential energy use during the CORONAVIRUS pandemic has risen by 15% to 20% compared to the same period last year. Some people are now opting to Install Solar PV and Water Heating Systems to help bring down the rising energy bills.

Eenovators Limited has over the years trained hundreds of professionals in Energy Efficiency, Energy Management and Renewable Energy. In Kenya, Eenovators is a recognized training provider certified by the National Industrial Training Authority (NITA) to carry out energy training.

Due to the rising demand for Solar Water Heating technicians, we have scheduled a Solar Hot Water training on 22nd and 23rd September at the Best Western Plus Meridian Hotel. All recommendations from the Ministry of Health on Coronavirus prevention will be observed. More details below;