What is the most energy efficient hot water system?

Soltaro AIO Hot Water Heat Pump situated at rear of house
25th February 2025

We all want the most efficient energy systems in our homes, and it comes no surprise that heating hot water is second only to heating or cooling the house in terms of energy priorities.

However, what is the most energy efficient way to heat your hot water?

As energy costs continue to rise and sustainability becomes a top priority for homeowners, finding the most efficient way to heat water is more important than ever. Among the various options available, hot water heat pumps stand out as the most energy-efficient solution. When combined with excess solar energy, they offer even greater savings, making them an ideal choice for eco-conscious households looking to reduce both their carbon footprint and electricity bills.

How Hot Water Heat Pumps Work

A hot water heat pump operates differently from traditional electric or gas water heaters. Instead of directly generating heat, it extracts heat from the surrounding air and transfers it to the water in the storage tank. This process is similar to how a refrigerator works but in reverse.

Since heat pumps move heat rather than create it, they use significantly less electricity than conventional water heaters, making them an energy-efficient and cost-effective choice.

Why Are Hot Water Heat Pumps the Most Efficient Option?

Compared to traditional water heating systems, hot water heat pumps can be up to four times more efficient. Here’s why:

  1. Lower Energy Consumption

Traditional electric resistance water heaters convert electricity directly into heat, which is an inefficient process. Gas water heaters burn fossil fuels, losing energy through exhaust gases. In contrast, heat pumps use 70-80% less electricity by leveraging ambient air heat, significantly reducing energy waste.

  1. High Coefficient of Performance (COP)

A key measure of efficiency is the Coefficient of Performance (COP), which represents the ratio of heat output to energy input. Electric water heaters typically have a COP of 1, meaning they produce one unit of heat for every unit of electricity used. Heat pumps, however, can achieve a COP of 3 to 4, meaning they generate three to four times more heat than the electricity they consume. In the case of the Soltaro AIO Hot Water Heat Pump, it can achieve a COP of 4.15, higher than its competitors.

  1. Lower Operating Costs

Due to their high efficiency, heat pumps lead to substantial savings on electricity bills. While the upfront cost may be higher than traditional systems, the long-term energy savings quickly offset the initial investment. Many households experience 50-75% lower water heating costs after switching to a heat pump.

Maximizing Savings with Excess Solar Energy

For homeowners with solar panels, pairing a hot water heat pump with excess solar generation further increases savings. Here’s how:

  1. Utilising Surplus Solar Power

Solar panels often produce more electricity than a household consumes during daylight hours. Instead of exporting excess power to the grid for a low feed-in tariff, a heat pump can store that excess energy as hot water, essentially acting as a thermal battery. Soltaro have designed their AIO Hot Water Heat Pump with even more flexibility as the back up element is larger to store even more solar energy.

  1. Time-Based Heating Optimization

By programming the heat pump to run during peak solar production hours, homeowners can use free, renewable energy instead of drawing power from the grid. This reduces reliance on nighttime grid electricity, lowering energy bills even further.

  1. Reducing Carbon Footprint

When powered by solar energy, a hot water heat pump becomes virtually carbon-neutral, eliminating the need for gas or fossil-fuel-based electricity. This contributes to lower greenhouse gas emissions and a more sustainable home.

Conclusion

Hot water heat pumps are the most efficient, cost-effective, and environmentally friendly water heating solution available today. Their ability to extract heat from the air significantly reduces electricity consumption, leading to lower energy bills. When paired with excess solar energy, they become even more beneficial, allowing homeowners to maximise their renewable energy use and further cut costs.

With rising electricity prices and increasing concerns about sustainability, investing in a hot water heat pump—especially when combined with solar power—is one of the smartest moves a homeowner can make.

Find out about the solar optimised All-in-One Hot Water Heat pump from Soltaro by clicking here.

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