Up until last June, the simplest way to improve the EPC rating of a Commercial property was to change the lighting to LEDs, the more efficient (in terms of lumens per circuit Watt) the better.
At that time, gas was king for heating, any direct-electric heating in an office had a dire effect on the EPC-rating. All this changed in June ’22 when the CO 2 emissions of electricity was revised downwards to reflect the increased contribution of renewable energy to the national grid.
Commercial EPC ratings are based on the calculated CO 2 emissions of the fuels used to heat, cool, ventilate, light and provide domestic hot water to the property. This change had the effect of reversing the previous situation, so now gas heating is the work of the devil and electric heating (preferably heat pumps) is good.
This change also meant that efficient lighting was less important (in a heated area) as any inefficiency just means waste heat is being generated and, for a building heated by direct-electric (e.g. an electric convector heater) then there may no EPC rating improvement to be had from fitting energy-efficient lighting.
This all makes sense with the drive to move to renewable and low-carbon energy.
I wish Domestic EPCs were rated in the same way, but they are not, they are based on the calculated cost of space and water heating and lighting the dwelling.
Hopefully the rating will be changed to reflect the reason for having EPCs in the first place – reducing CO 2 emissions.