Heat-pump hot water + solar PV: get the timing right and save more

A heat pump already cuts your hot-water bill by 60–75%. Add solar panels, and you can push that bill close to zero.

The trick isn’t just owning both—it’s using them together.

Timing is everything

Solar panels make the most power from late morning through mid-afternoon. That’s when you want your heat pump to run. If it kicks in at night, you’re just drawing from the grid.

Think of your tank as a thermal battery. It stores the sun’s energy as hot water for later.

Smart scheduling

Use a simple timer to run the system during sunny hours.

Plan your legionella cycle for mid-day once or twice a week, not in the middle of the night.

If you’re on a special night tariff, compare the maths—but for most households, daytime heating wins.

Tank vs lithium battery

Batteries are expensive. A hot-water cylinder is already in your home. Using it as a storage device is often the cheapest way to capture and keep solar energy.

Emerald advantage

Our Emerald all-in-one units have smart timer options built in. Pairing PV and hot water doesn’t get simpler.

A day in the life

Panels start producing by mid-morning. Set your heat pump to run from 10 am to 2 pm. By evening, the tank is full of hot water—paid for by the sun.

No juggling. No spreadsheets. Just simple savings.

The bottom line

Heat pumps are efficient. Solar is free. Put them together and you’ve got one of the smartest upgrades a Kiwi household can make.

👉 Book a free quote and start saving more.