See live monitoring data from this system on HeatPumpMonitor.org:
https://heatpumpmonitor.org/dashboard?id=748In this video I document my installation of a heat pump in a 1979 Bungalow. While I am not a professional installer, I used data from OpenEnergyMonitor to guide my design which replaced an old oil boiler with an air source heat pump.
My home is a 140m² bungalow built in 1979 with cavity wall insulation. To ensure accurate sizing, I performed a blower door test which measured 0.4 Air Changes per Hour (ACH). Using a conservative 0.6 ACH figure, I calculated a heat loss of 5.6kW at -2°C. (Had I used standard default assumptions, this would have been overestimated at 8.4kW).
Flow Temperature: To achieve a target SCOP of 4+, I designed the system to run at a low flow temperature of 40°C and am upgrading old radiators to K2 convector units.
Unit Selection: I selected a 9kW Grant Aerona 290. I used a calculation based on electrical current input (Amps) to estimate the real-world maximum heat output, determining that the 9kW unit offers a ~30% "oversize" margin. This allows for comfortable heating without the risk of falling short, which the smaller 6.5kW unit might have done.
Hot Water: I installed a custom 250L Heat Geek super cylinder with upgraded insulation and a large coil for high efficency DHW.
Hydraulics: I opted for a fully open-loop system utilizing existing pipework but added a 50L volumiser to experiment with system volume. I minimized external pipework to reduce heat loss.
The system is equipped with Level 3 OpenEnergyMonitor metering. I am projecting a SCOP of 5+ for space heating and 3.9 for hot water. By switching from oil to this heat pump setup, I expect to reduce carbon emissions by 85% and halve my running costs.
OpenEnergyMonitor Level 3 Monitoring Bundle:
https://shop.openenergymonitor.com/level-3-heat-pump-monitoring-bundle-emonhp/