Solar-powered heating systems are becoming more popular as governments encourage a transition away from fossil fuels to renewable alternatives and consumers look for ways to reduce their utility bills. Just like residential solar panels that provide consumers with electricity, solar heaters are being installed in homes around the globe as part of government initiatives as well as privately. 

Solar water heating systems include a storage tank and a solar collector. There are two types of systems available: active, which have circulating pumps and controls, and passive, which do not. There are two types of active solar water heating systems: direct circulation systems, which have pumps that circulate household water through the collectors and into the home and indirect circulation systems, which have pumps that circulate non-freezing, heat-transfer fluid through the collectors and a heat exchanger, heating the water that flows into the home. The latter works more effectively in cold climates than the former.  

Passive solar water heating systems are generally less expensive than active systems, although not as efficient. However, they can be more reliable and last longer. There are also two basic types of passive systems. The Integral collector-storage passive system has a storage tank covered with a transparent material, which allows the sun to heat the water before delivering it to the plumbing system. Thermosyphon systems work by heating water in a collector on the roof before transporting it to the plumbing system when a hot water faucet is opened. Most of these systems have a 40-gallon capacity.  

As they rely on solar power, these systems typically require a backup system for cloudy days and times of high demand. Backups can come in the form of conventional storage water heaters or as part of the solar collector, such as rooftop tanks with thermosyphon systems. Solar water heaters need to be maintained every three to five years and some parts may need replacing every two to 10 years. Once installed, they can massively reduce consumer utility bills, particularly in regions with greater solar irradiance.

In Europe, Cyprus has the largest proportion of solar-powered water heaters. The island country in the eastern Mediterranean Sea is embracing solar heaters to take advantage of its favourable weather conditions, support a green transition, and help reduce consumer energy bills. Around 93.5 percent of households now use solar water heaters, which has helped Cypris to exceed its renewable energy targets for the heating and cooling of buildings. 

Cyprus’s environment commissioner Charalampos Theopemptou stated, “There are many areas where Cyprus has not achieved greenhouse gas emission goals… But in terms of renewable energy resources being used for the sustainable heating and cooling of buildings, we’ve met the target easily, precisely because of such extensive utilisation of solar water heaters for so many years.”

Cyprus has been using solar water heaters since the 1960s, putting it way ahead of most other countries. The technology became popular as it requires just solar panels, a tank and copper pipes – as well as the right weather conditions. On average, Cyprus enjoys over 300 days of sunshine a year, making it the perfect environment for the technology. The rollout of solar heaters has led to the development of a domestic manufacturing industry and the creation of many jobs. Although installation costs have risen over the years, there are EU-funded grants for households looking to install solar heaters. 

In the Middle East and North Africa region, solar-powered water heaters have also grown in popularity in recent years. In Jordan this September, the Energy and Mineral Resources Minister Saleh Kharabsheh launched phase two of the government’s solar heater subsidy programme, which covers 30 percent of the cost. The scheme will support the installation of 5,000 solar systems at a cost of up to $4.2 million. The previous phase saw the installation of 3,500 solar water heaters. 

In Egypt, three out of four households relied on butane cylinders just a decade ago, as there was little access to a grid-connected supply of natural gas. In 2023, Egyptians consumed around 800,000 butane cylinders a day, many of which were subsidised by the government. This has encouraged many households to invest in solar-powered water heaters in recent years. In 2024, Egypt’s solar water heater market is estimated at over $100 million, as it deploys its UNIDO-backed Solar Heating in Industrial Process (SHIP) programme. There are now 11 solar heater manufacturing operations in Egypt and the government is looking to strengthen ties with Tunisia and Jordan to grow the market further. 

The solar water heater market value is expected to increase from $4.26 billion in 2023 to around $6.18 billion by 2028, with a compound annual growth rate of 7.4 percent. Asia-Pacific is expected to be the fastest-growing region for solar water heaters in this period. Industry growth will be supported by technological innovation, as companies introduce predictive analytics and artificial intelligence into their heaters to improve performance. The market will largely be driven by government policies to transition away from fossil fuels to green alternatives, national and regional grants for disadvantaged communities, and the increased consumer demand to reduce their energy bills.  

By Felicity Bradstock for Oilprice.com 

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