This simulator models the real energy budget of a wellness centre — a gym/spa floor with lighting, an HVAC system and occupancy-driven equipment — as three additive power draws computed from an explicit building-load equation, not a cosmetic mockup. Move the thermostat setpoint against a time-varying outdoor temperature to see the heat pump's electrical load swing between heating and cooling, dim the lighting to cut its share instantly, and raise occupancy to load up treadmills, sauna heaters and pool pumps. The 3D scene mirrors every number: fixtures glow with brightness, vent particles carry heat-flow color and density proportional to HVAC power, and the equipment bay animates with occupancy, while the day-cycle sun drives the outdoor temperature the thermostat has to fight. A running projection integrates the HVAC load across a full simulated day to report total energy, cost and CO2 output.