How does the new system work?
In theory, the new boiler will carry most of the load for heating and hot water during the colder months. In warmer months, when higher ambient temperatures permit lower flow temperatures, the heat pump will come into its own.
What else have you done?
We’ve replaced the old 150 litre domestic hot water cylinder with a 200 litre cylinder. We should see some savings because there’s a larger volume of stored hot water that will need less frequent re-heating.
What has the change meant in terms of energy costs?
Overall costs have gone up massively because of rising energy prices But in comparing figures for the first eight months against those for the same months last year, our electricity increased slightly from 3,004 to 3,2139kWh, but gas fell from 7,400 to 6,483kWh – an overall saving of 782kWh.
How is the new system performing?
The system performs very well, but I can’t tell exactly how much is from the heat pump and how much is from the boiler. Now that the weather is warmer, the heating is off completely and I've also lowered the temperature on the cylinder to 50 degrees which the heat pump can handle on its own.