# Commercial heat pumps and what they do to an EPC rating > Why a heat pump changes the fuel the assessment sees as well as the efficiency, and what has to be true of the fabric first. Source: https://commercialepcupgrades.co.uk/measures/heat-pumps --- # Commercial heat pumps and what they do to an EPC rating Most measures make the same system use less energy. A heat pump replaces the system and changes the fuel, which means its effect on a rating depends on how the assessment weighs electricity against gas, not just on how efficient the unit is. That is why two buildings can fit the same heat pump and see very different rating movements. Large capital, and the rating effect depends on the model, not the unit ## Why the rating effect is not obvious A heat pump delivers more heat than the electricity it consumes, which is a genuine efficiency gain. It also moves the building from one fuel to another, and the assessment applies different factors to those fuels. The rating outcome is the combination. The practical consequence is that this is a measure to model for your specific building before committing, rather than to assume. It is also a measure whose rating benefit can change when the factors are updated, independently of anything you do to the building. ## The fabric has to be ready A heat pump produces heat at a lower temperature than a gas boiler. A building with poor fabric and emitters sized for high flow temperatures will be cold, or will run the heat pump hard and inefficiently to compensate. So fabric and emitters come first in the design even where they come second in the programme. Retrofitting a heat pump into an unimproved building and hoping is the most common way this goes wrong and gets blamed on the technology. - Heat loss calculated for the actual building, not assumed from floor area. - Emitters sized for a lower flow temperature, which often means larger radiators or a different distribution system. - Fabric improved enough that the required flow temperature is achievable. - Electrical supply capacity confirmed, because this is a significant new electrical load. ## Where it suits a commercial building Buildings with a steady, moderate heat demand and reasonable fabric. Buildings already running on electric heating, where the comparison is against direct electric rather than gas and the case is much stronger. Buildings with a simultaneous heating and cooling demand, where the plant can do both. Less well: buildings with very high intermittent demand, poor fabric, or constrained electrical supply. ## The supply upgrade question A heat pump is a significant electrical load, and so is EV charging, and so is any electrification of cooking or process. Several of those arriving together can push a building past its incoming supply capacity, and a supply upgrade is expensive and slow. If more than one of them is on the horizon, establish the available capacity early. It changes the order you do things in, and occasionally it changes what is possible at all. ## Questions we get asked ### Will a heat pump improve our EPC rating? ### Do we need to improve the building first? ### Will it need an electrical supply upgrade? Sources - A non-domestic EPC is an asset rating: it is based on the fabric of the building and its services rather than on metered consumption. [A guide to energy performance certificates for the construction, sale and let of non-dwellings, DCLG, 2014](https://www.gov.uk/government/publications/energy-performance-certificates-for-the-construction-sale-and-let-of-non-dwellings) Last updated 8 October 2026 . - [Heating and hot water The rest of the heating picture](https://commercialepcupgrades.co.uk/measures/heating-hot-water) - [Fabric What has to be true first](https://commercialepcupgrades.co.uk/measures/insulation-and-fabric) - [EV charging The other load competing for your supply](https://commercialepcupgrades.co.uk/measures/ev-charging) Next step ## Get heat pumps priced for your building Tell us the building type, the floor area and the rating you are on now. One commercial contractor comes back to you with a quote off a survey. Or call [07367 293494](tel:+447367293494). Monday to Friday, 9am to 5.30pm.