Solar Water Heaters

All You Need to Know

Air source heat pumps use an innovative and energy efficient water heating technology that is quickly replacing the traditional Solar Water Heaters and Electric Heaters for residential and commercial use.

An air source heat pump is a system that absorbs heat energy from the surrounding environment and transfers the energy to water, thereby creating an eco-friendly heating system.

This type of water heaters use about a 30% of the electricity of standard electric water heaters because they take advantage of existing heat in the air.

Types of Solar Water Heaters

All the designs consist of two main components; a collector (panel) to harness the sun’s thermal energy (heat), and a storage tank to store the hot water.

Solar water heaters are defined according to three main criteria: the manner in which water is heated, the collector type, and the water circulation method. Therefore, to fully describe the required solution, one must state where it falls in each of the three categories.

Components of a Heat Pump Water Heater

A heat pump water heater is a relatively straightforward system to understand. The system can be broken down into nine main components:


  • Tank: Like a standard water heater, a key component of the heat pump water heater is an insulated water storage tank.

  • Compressor: Usually located at the top of the heat pump water heater, the compressor pressurizes the refrigerant inside the evaporator and condenser coils causing it to expand and heat up. This also propels it throughout the system.

  • Evaporator: The evaporator coils are located near the top of the heat pump where they can collect warm air pulled in via the fan. The refrigerant, which runs inside, warms up, is compressed, and evaporates creating high pressure and high heat.

  • Condenser: Located either surrounding or inside of the water tank, the condenser coils are where the refrigerant loses pressure, cools and condenses back to a liquid. In doing so, it releases the hot temperature to the water inside the tank.

  • Fan: The fan, located at the very top of the heat pump water heater, is responsible for pulling in ambient warm air from the surrounding environment.

  • Thermostats: Most hot water heaters will have two thermostats—one to measure the water temperature at the bottom of the tank and one to measure at the top. These thermostats control the system, telling it to either heat the water up or stop heating temporarily.

  • Cold Water Inlet: This is the inlet pipe where cold water comes in from your home’s main line.

  • Hot Water Outlet: This is the outlet pipe where now-heated water leaves the water heater to go to your shower, sink, washing machine or dishwasher.

  • Drain: This is a release drain at the bottom of your water heater if you ever need to drain any water out of the tank.

Cost of Heat Pump Water Heaters

Heat pump water heaters cost slightly more than traditional solar water heaters. Below is a list of the common sizes in the market and their indicative prices.

Cost of Heat Pump Water Heaters


Indicative Price (KSh)

150 Liters


200 Liters


300 Liters


Luckily, after the initial cost, a heat pump will save you about 70 – 80% of the usual cost of heating water using electric water heaters.

Are Heat Pump Water Heaters Worth It?

Whether you’re thinking about a new solar water heater or trying to find a way of reducing a high electricity bill due to an existing electric water heater, you might find it worthwhile to consider a heat pump.

Heat pumps are significantly more energy efficient than standard electric water heaters because instead of using energy to generate new heat, they collect existing ambient warmth and transfer it to the water. This efficiency can save you hundreds of dollars on energy bills each year.

As opposed to solar water heaters that rely on direct sun’s radiation to heat water, and whose performance is directly affected by the weather and orientation relative to the sun’s path, heat pumps can be installed anywhere in the house and only use a little amount of electricity to heat water all day and night. The fact that they are rated about 400 – 600 watts means they can be powered by your Solar Home System just like the other household appliances!

Ready to get a Heat Pump?

Find out more information on selection, costing, and installation by contacting us today!

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