At Energy House 2.0, we recently put the York YKF 5Kw Monobloc Air Source Heat Pump (ASHP) through its paces to assess its performance in real-world conditions. Working alongside BRS Heat Pumps, we tested the unit in a specially controlled environment designed to replicate typical and extreme UK weather conditions.
With the push for more sustainable home heating solutions, it’s crucial to understand how heat pumps perform across different temperatures.
Test Conditions
The aim of this series of tests was to provide a series of steady state and dynamic tests of the heating system on the Vector V1 Property located within one of the Environmental Chambers at Energy House 2.0. This was carries out to obtain the following metrics
- Air Temperatures
- Energy output of ASHP
- Energy Consumption
- Coefficient of Performance (COP)
- Running Costs
- System Energy Efficiency Indicator (SEEI)
The tests were spilt into two categories
- Constant: The test house was heated continuously over each 24h period
- SAP: The test house was heated using the SAP pattern of 07:00-09:00 and 16:00-23:00
The internal setpoint temperatures were based on SAP with a 21°C setpoint in the single zone. Tests were then conducted at external temperatures of 5°C, -5°C, -10°C to simulate typical and extreme UK weather conditions.
The York ASHP showed strong results across various scenarios:
- Maintained stable indoor temperatures, even at -10°C.
- Demonstrated high energy efficiency, particularly in milder conditions.
- Showed that using a ‘setback temperature’ could enhance performance under on-off heating schedules.
- During a typical UK Winter Day 5°C it would cost £2.05 per day to run the York ASHP in a contact heating pattern.
Read the full report here: BRS Report




BRS Heat Pumps held a Future of Heat Pumps expo at Energy House 2.0 in February 2025 which provided space for installers, specifiers and policymakers to come together to exchange ideas, with Richard Fitton sharing details of our groundbreaking research and Olivia Smalley from the Heat Pump Association (HPA) outlining key policy shifts within the sector.