EPCS | EXISTING HOTELS The study showed that we must find out much more about our buildings before rushing in and installing the latest fad technology PV panels to the hotels roofs and car parks. A tool was then created to look at each of the hotels individually and understand what EEMs can be added to the building. Its outputs included the old 2013 EPC prediction, the current (2021) EPC prediction, and the actual operation prediction (see Figure 2). EEM1 is the addition of LED lighting, EEM2 is replacement of the hot water and heating system with a heat pump, and EEM3 represents fabric improvements. There is a button to include PV or exclude it for each option. The purple dashed line around the EEM1 solution for this hotel shows that the operational energy here is predicted to be negative this shows a 10 year payback on the LED lighting and PV installation. The predicted EPC, using current regulations, is a D and using the future carbon factors it is predicted to be a C. To achieve the required B, a heat pump needs to be installed; however, this is unnecessary as the hotel would already be operating at net zero carbon emissions, so the EPC improves but the payback increases, and the energy savings dont change. This was the case for multiple hotels and can be seen in the wider analysis paper presented at the CIBSE Technical Symposium 2022. From this study, it became clear that the database for the NCM needs to be reviewed and updated especially in relation to: SET NCM INPUTS Domestic hot-water flowrate 31.68 L.h-1 The domestic hot water follows the occupancy schedule; in other words, it is expected that hot water will be used at peak flowrate from 11pm to 7am Full load hours daily for domestic hot-water usage = 10.25 Occupancy = 1 person/20m2 = 0.9 people Hot water used per day per room = 292 litres The fresh air for the EPC is set at 0.932 l.s-1.m-2; the exterior wall area is 10.76m2 The total outdoor air entering the bedrooms is 16 l.s-1 person The heating setpoint temperature is a steady 20C, 24 hours a day, year round Domestic hot water for all categories (similar issues have been found for student accommodation and highdensity apartment buildings). Creating different categories for hotel buildings, as roadside hotels operate and are built very differently from city centre ones. It is my suggestion that an alternative compliance path should be created for existing buildings. In this case, a building owner can prove their year-on-year savings with actual metered and reported data. The study also showed that we must find out much more about our buildings before rushing in and installing the latest fad technology. We need to step back and look at the whole building, measure it, analyse it, and improve it from there. CJ DR ANNIE MARSTON is chief product officer at REsustain. This work was undertaken with Finlay Milliner, while she worked at Hydrock as technical director leading the building physics team. The full paper can be read in the CIBSE Technical Symposium 2022 paper bit.ly/CJOct22AM 56 October 2022 www.cibsejournal.com CIBSE Oct 22 pp54-56 Hotel EPCs Supp.indd 56 26/09/2022 16:11