By Ivana Moric, Principal Consultant — Energy
If you operate a hotel or leisure facility in the UK, heating and hot water probably account for somewhere between 50% and 70% of your total energy bill. That’s a substantial number. But the more revealing figure is this: in our experience working on energy-intensive leisure and hospitality buildings, the typical property wastes 20–35% of that heating spend on inefficiencies that are entirely fixable.
The waste doesn’t announce itself. It accumulates in systems that were installed years ago, sized for conditions that have changed, and maintained to keep running rather than to run well. Here are the three most common sources of overspend we encounter — and why most hotel operators don’t spot them.
1. Oversized boilers running below their efficient load
Most hotel boilers were sized for the coldest day of the year at full occupancy. That’s perhaps 10 days annually. For the remaining 355 days, the boiler is running significantly below its rated capacity, which is where gas boilers become inefficient.
A boiler rated at 400kW running at 25% load doesn’t use 25% of the gas. The losses from cycling (firing up, shutting down, firing up again), standing heat loss from the body of the boiler, and flue losses at part-load mean it might consume 35–40% of full-load gas to deliver 25% of full-load heat. Across a year, this adds up to thousands of pounds.
The fix isn’t necessarily replacing the boiler. Often it’s adding a smaller lead boiler for baseload, improving sequencing controls, or — increasingly — installing a heat pump to handle the baseload demand with the existing boiler covering peaks only. The payback on these interventions is typically 3–5 years, sometimes faster when paired with available grants.
2. HVAC operating on fixed schedules regardless of occupancy
Walk through a hotel corridor at 2am on a Tuesday in February. The heating is running. The ventilation is running. The corridor lighting is on. Occupancy might be 30%.
Many hotels still operate HVAC systems on fixed time schedules rather than responding to actual demand. The ventilation runs at the same air-change rate whether the restaurant has 80 covers or 5. The heating in unoccupied rooms maintains the same setpoint as occupied ones, or worse, has no room-level control at all.
Occupancy-based controls — even relatively simple ones like CO2-sensing ventilation and room-level presence detection linked to setpoint adjustment — can reduce HVAC energy consumption by 15–25% in a typical hotel. The technology is mature, the installation is usually non-disruptive, and the payback is often under 3 years.
The reason this persists in so many properties is that it falls between responsibilities. The facilities team keeps the systems running. The operations team manages guest experience. Nobody is tasked with asking whether the systems are running more than they need to.
3. Hot water generation with no heat recovery
Hotels consume a large volume of hot water — for guest rooms, kitchens, laundry, and cleaning. In most properties, this hot water is generated entirely by gas boilers or immersion heaters with no recovery of the heat that’s already being generated and then wasted elsewhere in the building.
The ventilation system in a hotel is constantly extracting warm, humid air from bathrooms, kitchens, and swimming pools (if present) and dumping it outside. That air carries a significant amount of thermal energy. A heat recovery system on the extract ventilation can pre-heat incoming fresh air or pre-heat the incoming cold water feed, reducing the load on your boilers by 10–20%.
Similarly, greywater from showers and baths leaves the building at 30–35°C. Drain water heat recovery systems — relatively simple passive heat exchangers on the wastewater pipes — can capture a portion of that energy to pre-heat the cold water supply. These systems are low maintenance, have no moving parts, and can reduce hot water heating costs by 10–15%.
Neither of these technologies is new or experimental. They’re standard practice in new-build hotels. The issue is that existing properties were built without them, and nobody has assessed whether retrofitting them makes financial sense. In most cases we’ve analysed, it does — comfortably.
What these three issues have in common
None of them is visible in your monthly energy bill as a separate line item. The bill just shows total gas consumption and total electricity consumption. You can’t see the portion wasted by an oversized boiler, the portion spent heating empty rooms, or the portion that went down the drain as hot greywater. It all just looks like “energy costs.”
This is why a structured energy assessment — one that measures consumption by system and benchmarks it against comparable properties — reveals savings that aren’t apparent from the headline numbers alone.
Where to start
If you haven’t had an independent review of your property’s energy performance, the first step is understanding where you actually stand. We’ve built a free benchmarking tool that compares your hotel against industry benchmarks in under two minutes. It won’t replace a full assessment, but it will give you a clear indication of whether there’s a conversation worth having.
Or if you’d prefer to discuss your property directly, book a 30-minute consultation. We’ll give you an honest assessment of what’s worth pursuing.
ENEREKA is an independent energy consultancy specialising in decarbonisation strategy for commercial and industrial organisations. We have no commercial relationships with equipment suppliers — what we recommend is based on what works for your building and your budget.
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