Solar panels covered in snow, yet still functioning

24 Aug. 23

Do Solar Hot Water Systems Work in Winter? A Deep Dive

As a solar hot water plumber in Sydney with over 20 years of experience, I often encounter a common concern among homeowners: “Do solar hot water systems work in winter?” Today, we’ll address this question and explore the performance of solar hot water systems during colder months.

Understanding Solar Hot Water Systems

Before delving into winter performance, let’s revisit how solar hot water systems work. These systems capture sunlight using solar collectors, typically mounted on a rooftop, and convert it into heat energy. This energy is then used to heat water stored in a tank for later use. Additionally, incorporating Thermal Solar Hot Water technology can enhance the efficiency of this process even during colder months. Thermal Solar Hot Water systems utilize specialized collectors and heat exchangers to maximize heat absorption from the sun and transfer it to the water, ensuring that the system can effectively provide hot water even in lower temperatures. This integration of Thermal Solar Hot Water technology adds a layer of resilience to solar hot water systems, allowing them to continue operating efficiently and sustainably throughout the year, regardless of seasonal variations.

Solar Hot Water Systems in Winter

The idea that solar hot water systems might struggle in winter stems from a basic misconception: the systems need hot weather to work. In reality, they need sunlight, not heat. As long as there is sunlight, a solar hot water system can produce hot water, even if the air temperature is cold.

Here’s how:

  1. Solar Collectors: The two common types of solar collectors – flat plate and evacuated tube collectors – are designed to capture and retain as much heat from the sun as possible, even on cloudy days. Particularly, evacuated tube collectors are highly efficient, with a vacuum between the two layers of glass to reduce heat loss, allowing them to perform well in colder climates.
  2. System Design: Many solar hot water systems include a gas or electric booster, which automatically heats the water if the solar energy isn’t sufficient, ensuring a continuous hot water supply, even in less-than-ideal conditions.
  3. Sunlight vs Heat: As long as there is sunlight, your solar hot water system will work. Solar radiation reaches the earth even on cold, overcast days, and these rays can be harnessed to heat your water. In fact, Australia’s solar radiation averages a high of 58 million petajoules of energy per year, more than enough to supply the nation’s energy needs, according to Geoscience Australia.

Optimizing Your Solar Hot Water System for Winter

While it’s true that solar hot water systems can work efficiently during winter, here are some tips to maximize their performance:

  1. Ensure Correct Installation: The position and tilt angle of solar collectors should take into account the sun’s lower winter path. This ensures the collectors receive maximum sunlight during shorter winter days.
  2. Regular Maintenance: Regular servicing ensures your system operates at peak efficiency year-round. Servicing should include cleaning the solar collectors to ensure maximum sunlight absorption and checking the system’s components for wear and tear.
  3. Use a Timer: If your system has an electric or gas booster, consider using a timer to limit boosting to off-peak hours, helping to save energy and reduce costs.
Close-up of evacuated solar tubes during winter conditions

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Embracing Solar Energy All Year Round

In the words of former U.S. Secretary of Energy, Ernest Moniz, “The cost of solar energy has not been opened up because the oil industry does not own the sun.” Solar energy is a free, abundant resource we can harness throughout the year, including during winter.

Rest assured, as a solar hot water plumber, I am committed to ensuring your system delivers hot water all year round, rain or shine, summer or winter. With the right system, proper installation, and regular maintenance, you can enjoy the numerous benefits of solar hot water even in the chilliest of months.

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