Heat Pump Using High Electricity in Summer – Hot Water Setup Issue

System Type: Air Source Heat Pump (Domestic) LG

Issue Type: Hot Water Configuration / Running Costs

The Problem

A homeowner in North London contacted me after noticing unusually high electricity bills.

What stood out straight away was that the system was using a large amount of energy even during warmer weather, when heating demand should have been low.

What I Found

After reviewing the system setup and looking at monthly kWh usage, it became clear that the issue wasn’t with the heating — it was how the hot water system had been configured.

There were two key problems:

• The hot water circulation pump had been left running 24 hours a day

• The hot water was being heated using the immersion heater instead of the heat pump

The circulation pump constantly moves hot water around the system. If left on permanently, it causes continuous heat loss, meaning the system has to keep reheating water throughout the day.

On top of that, the immersion heater was doing the work instead of the heat pump — which is far more expensive to run.

What I Changed

• Set up the hot water circulation to run on a timed schedule rather than continuously

• Switched the system back so the heat pump heats the hot water instead of the immersion heater

• Explained to the homeowner how and when to use the circulation system properly

The Outcome

With the system configured correctly, hot water demand reduced significantly and the heat pump was able to operate as intended.

The unnecessary energy usage was eliminated, and the homeowner saw a noticeable reduction in electricity consumption.