Surplus solar power could heat household water in NL after 2027

Households that replace a modern gas boiler with a heat-pump boiler for hot water could cut their annual hot-water energy costs by between €110 and €329, according to calculations by manufacturer Dimplex Benelux.

The figures are modelled savings in running costs only. They do not include the cost of buying, installing or maintaining the equipment.

Dimplex compared a gas boiler up to five years old with its Edel range of heat-pump boilers, which draw heat from the surrounding air. A two-person household using 70 litres of hot water a day would pay €243 a year with gas and €133 with a heat-pump boiler, the company said. For six people using 210 litres a day, the figures were €730 and €400.

That works out at a 45% reduction for every household size. The percentage follows from the company’s assumptions: an electricity price of 30 cents per kWh, a gas price of €1.66 per cubic metre, water heated to 55°C, and a heat-pump boiler producing three units of heat for every unit of electricity it uses.

Tested performance across the Edel range runs from 2.38 to 3.19 units of heat per unit of electricity, depending on the model, so savings with lower-rated models would be smaller. Dimplex said the savings were not guaranteed and would change with water use, equipment and energy prices.

Solar power
The calculations assume all electricity is bought from the grid. Households with solar panels can reduce that further by using surplus daytime power to heat and store water, the company said. This needs a compatible solar inverter or switching module.

The Netherlands’ net metering scheme, which lets households offset the solar power they export against the electricity they take from the grid, ends on 1 January 2027, the government says. Households will still be paid for the power they export, but the payment will no longer cancel out what they buy.

Where buying electricity costs more than the export payment, using solar power at home will become more valuable, Dimplex said.

“Solar panels do more than power appliances,” Sander Zijnstra, trade marketing manager at Dimplex Benelux, said in a statement. “Combined with the right hot-water technology, surplus daytime generation can be turned into hot water for use later.”