Heat Pump System Optimization in a Hotel – The Economic Upside of Precise Design

The owner of a 25-room, 3-story hotel approached our engineering office with a problem: operating the existing pellet-boiler heating system had become unsustainable as fuel prices rose. No natural gas network was available, and installing an outdoor LPG tank would have been even less economical.

Technical diagnosis and design of the bivalent system

Based on the data provided and on-site surveys, we prepared a feasibility study. The biggest challenge was that the building’s existing radiator system required a high flow temperature — something heat pumps alone can’t produce economically during the coldest winter days.

Based on detailed engineering calculations, we designed a bivalent (heat-pump-assisted) system. The heat pumps can cover heating entirely on their own down to an outdoor temperature of -2 °C, which accounts for 85–90% of the whole heating season. On the rare, extremely cold days above that threshold, the existing pellet boilers kick in as a peak heat source, while the heat pumps took over domestic hot water (DHW) production 100% of the year.

Economic results and the power of a construction design

Heating and DHW costs were cut by roughly 60%. Thanks to the site’s previously oversized solar PV system, the investment’s payback period shrank from 8.5 years to 5.5 years.

The risk-reducing role of a proper construction design was equally clear: without one, contractor quotes on the market varied chaotically between HUF 29 million and HUF 47 million, because contractors priced in their uncertainty with an inflated estimate. Once we produced the detailed MEP construction design, we were able to lock in a fixed price of HUF 35 million with the winning contractor, based on an accurate bill of quantities. Thanks to the precise design and on-site design supervision, the project’s extra-work costs came to just HUF 500,000.