MCS has published a four-week consultation on updates to MCS 026.
MCS 026 is mandatory in MCS 007 (Heat Pump Product Standard). It is used to calculate Seasonal Space Heating Energy Efficiency (SSHEE) and to produce a table of SCOPs over a range of temperatures which is used in the creation of the MCS certificate.
Following industry feedback, this update accommodates air-to-air heat pumps and allows direct input of bivalent temperature (Tbiv). It also takes into consideration the 10% tolerance between heat demand and heat capacity allowed in EN 14825 and definitions have been updated to align with those in EN 14825: 2022.
This update incorporates the following changes:
- Performance test data at (non-standard) bivalent temperatures can now be input.
- Bivalent temperature calculation now recognises 90% heat load coverage by heat pump. For temperatures above the bivalent temperature, the calculation now recognises that when at least 90% of the target heat load is provided by the heat pump, the target heat load is considered to have been achieved (as described in BS EN 14825:2022). As a consequence of this, back up electrical heating is set to zero if at least 90% of the target heat load is provided by the heat pump (column K of worksheets.)
- The method for the determination of Tbiv has been updated (column R of worksheets)
- Heat Pump definitions have been updated to be consistent with those used in BS EN 14825:2022 – i.e. heat pumps now defined as either Low-, Intermediate-, Medium- or High temperature.
Air-to-air heat pumps
- Adding air-to-air heat pumps as an option for the heat source (and renaming the existing options to specify water as the internal heat transfer medium).
- Enabling input of heat pump performance data obtained using the test conditions for air-to-air heat pumps in Table 6 of BS EN 14825:2022.
- Incorporating the calculation procedure for SSHEE and SCOP included in Section 7 of BS EN 14825:2022 for air-to-air heat pumps (noting different procedures for heat pump capacities less than or equal to 12kW and for greater than 12kW).
- Included the option to input data for air-to-air heat pumps.
- Relevant column and row headings updated when air-to-air option is selected.
- On-mode, Thermostat-off and Crankcase heating hours updated to correspond to the hours defined for air-to-air heat pumps in BS EN 14825:2022, if the air-to-air option is selected.
- Default degradation coefficient for air-to-air set to 0.25 (instead of 0.9 for other HP).
- Flow temperature options updated to include 20oC for air-to-air.
- Formula for COPbin updated to match that in BS EN 14825:2022.
MCS would now like to invite comments from stakeholders. The deadline for submitting comments for this consultation is 12.00pm on Monday 28 April 2025.
Please send consultation responses to consultations@mcscertified.com using the form provided below:
