Environmental accounting in the accommodation sector measures resource use and operational emissions, but simplified boundaries capture only part of wider environmental impacts. The forthcoming European Product Environmental Footprint Category Rules (PEFCR) for Hotel Accommodation raise expectations for harmonised life cycle-based assessment. This study introduces the Hotel and Tourism Lodgings Dynamic Emissions Calculator (HTL-DEC), the first peer-reviewed operationalisation of the draft PEFCR applied across a multi-property hotel case study. HTL-DEC uses a two-layer reporting structure: (i) a PEFCR-aligned core for standard comparison and (ii) a reconciled extended layer with dynamic temporal resolution, source-level decomposition, supplementary per-guest-night reporting, hotel-specific room subtypes, and a modular scope extension. Temporal resolution applies to operational activity streams; capital-goods stages enter as fixed amortised contributions per room-night. Across seven hotels, environmental footprint scores per occupied room-night range from 0.05-0.23% of the average European citizen's annual environmental impact. Hotel operation contributes 70-86% of the single score, laundry emerges as the second-largest operational hotspot, and per-guest-night intensities reverse per-room-night rankings under variable occupancy. HTL-DEC also reveals seasonal swings and room subtype heterogeneity concealed by static aggregation. The study contributes a dual-purpose accounting architecture that preserves managerial diagnostic information without altering the standardised result.