Solar PV vs Solar Water Heater

 When talking about Solar Power or energy. 

People always think of the device installed on our roof to boil water used for showers.

This is the Solar Power device that we most commonly see and use. Or more specifically it is a Solar Water Heater.

This device is designed to absorb the heat from sunlight, and raise water temperature to produce hot water.

Most Malaysians need hot water for showers, thus we install Solar Water Heater so we can save electricity by generating hot water from the sunlight instead.

On the other hand, we have another type of Solar Power system, namely Solar Photovoltaic (PV) system.

This system is a totally different technology. It uses solar cells made of silicon to convert the Sunlight into electricity that can be used by our home appliances including the electric water heater.

Compared to Solar Water Heater, the Solar PV system comprises slightly more components. 

• The PV panels which convert Sunlight to Direct Current (DC) power.
• The DC cable which channels the DC current to the Inverters.
• The Inverters which convert the DC power to Alternating Current (AC) Power that are used by our appliances.
• The AC Cable which channels the AC power to our house from Inverters.
• And of course the circuit breakers etc that serve for protection purposes.

Compared to Solar Water Heater, Solar PV System requires more roof space, and also higher investment. But at the same time the resulting savings is also much higher.

On average we use about 60 liters of water for showers. Assuming the 30 liters of the water is heated from 25 deg C to 65 deg C.

Based on the above, the energy required shall be 1.4kWh per bath. (refer: https://www.omnicalculator.com/physics/water-heating#what-is-the-specific-heat-capacity)

A family of two, taking showers twice a day shall consume about 84kWh/month to generate hot water for showers.

If most of your electricity consumption is on the water heater, then installing a Solar Water Heater is an option for you.

But if you have electricity consumption for air-conditioner, iron, fridge, etc etc then installing Solar PV system may be a better option for you.