Heat pumps for hotels and resorts: guest water, laundry, dishwash and pool on one machine

A hotel’s heating bill is mostly hot water, and hot water is squarely in range for an industrial heat pump. Guest rooms need 45 to 70°C, laundry needs 60 to 85°C, dishwash rinse needs up to 82°C and pool water needs 26 to 30°C. One machine serves all four duties, on one circuit at different setpoints. Our Tetra Heat Pump units deliver continuous output to 120°C with ±0.5°C control. That covers every one of those duties, and none of the kitchen. Cooking and tandoor are above the range and stay on gas.

What does a hotel’s hot water system actually need?

A hotel has four duties, at four temperatures, with four different load profiles. The profiles matter as much as the temperatures.

Duty	Temperature	Load profile	Heat pump suitability
Guest room hot water	45 to 70°C	Two sharp peaks, morning and evening	Fits, with storage
Commercial laundry main wash	60 to 85°C	Steady through the working day	Fits
Dishwash sanitising rinse	To 82°C	Follows meal service	Fits
Swimming pool and spa	26 to 30°C	Continuous, seasonal	Fits, at the best COP in the building
Space heating and reheat	Low grade	Seasonal, by location	Fits
Kitchen cooking and tandoor	Direct flame	Meal service	Does not fit, stays on gas

The pool is worth a second look. It is the coldest duty in the building, so the lift from source to output is the smallest. The coefficient of performance is correspondingly the highest. A property that treats the pool as an afterthought misses the best duty in the building.

How do you size a hotel hot water heat pump?

Size it from the hot water draw. Room count is a proxy, and proxies vary by property type, occupancy and whether there is a laundry on site.

Four numbers produce the specification:

1. Daily hot water draw, in litres, from a meter or the boiler’s fuel consumption.
2. Delivery temperature, which is 45 to 70°C for guest water and higher for laundry and dishwash.
3. Inlet temperature, measured at the coldest point of the year. The heat load depends on the rise, not on the final temperature.
4. Peak draw rate and its duration, which sizes the storage, not the machine.

The load in kilowatts is then flow rate in litres per hour, multiplied by the temperature rise in °C, multiplied by 1.163, divided by 1,000. The sizing guide works two examples in full and gives the sensitivity of the load to inlet temperature.

Size the machine on the average through the day and the store on the peak. Sizing the machine on the peak is the common and expensive error: it buys capacity that runs for two hours and short cycles for twenty-two.

Why storage is not optional

A hotel does not draw hot water the way a heat pump likes to make it.

A heat pump is at its best running steadily at a set output. A hotel draws in two spikes, when guests shower before breakfast and again in the evening. Storage is what reconciles a steady maker with a spiky taker. Without it, the choice is an oversized machine or a cold shower at 8 am.

The volume follows from arithmetic. Take the peak draw rate, subtract what the machine produces in that period, and multiply the shortfall by the length of the peak. That is the usable volume the store has to hold. It is usable volume, not tank volume. Stratified water below delivery temperature serves nothing.

Two consequences follow for the building. A full store is a structural load, which matters when the plant sits on a roof or a podium. A tall, narrow vessel, fed cold at the bottom and drawn hot at the top, holds stratification far better than a short, wide one. So specify the tank shape.

In case the property already has solar water heaters on the roof, they can feed this same store as a preheat, and the heat pump then lifts from that temperature to delivery. Please note the timing, though: the collectors produce through the middle of the day, while the guest peaks are before breakfast and in the evening. Our heat pump vs solar water heater comparison explains how the two are combined.

What size of property does this suit?

It suits properties whose hot water demand supports a machine of 100 kW or more.

That is the smallest single unit built. In practice it means large resorts, convention hotels, and hospital, hostel and institutional campuses. On those sites the daily draw and the laundry load together justify the plant. A boutique property with thirty rooms and no laundry is better served by equipment sized for it. Our page on commercial water heaters for hotels sets out where a bank of geysers stops paying and one central plant takes over.

Where a group operates several properties, ask the question site by site. A resort with a pool, a laundry and a banqueting kitchen presents a very different load from a city hotel of the same room count.

Where does the plant go, and how loud is it?

Siting decides both questions, and they are usually the same conversation.

A water source machine has no fan array. The skid sits in a plant room with pipework to the source, and a plant room can be acoustically treated like any other room. An air source machine puts a fan bank outdoors. On a hotel, noise has to be designed into that configuration from the start. The design covers the distance to the nearest guest room and to the boundary, and whether an acoustic enclosure is in scope.

Three things determine what a guest or a neighbour hears. They are the configuration chosen, the distance and line of sight to the receiver, and the enclosure and anti-vibration mounts fitted. A decibel figure means something only with the distance, the operating condition and the measurement standard attached. We commit to a measured figure per project, quoted at a stated distance and condition. We design the installation to meet the ambient limit that applies at your boundary.

The other siting inputs are the weight of a full store, clearances for airflow and for service access, and a route for the water side. All three are issued on the general arrangement drawing at quotation.

Which fuel are you replacing?

Indian hospitality runs mostly on LPG, diesel and electric resistance. Against the fuels in this table, the arithmetic is not close. In case your hot water today comes from electric resistance heaters or an electric boiler, the comparison does not even need a fuel price, because both machines run on the same tariff. Our heat pump vs electric heater comparison works it through, including what the change does to your connected load.

Incumbent	Breakeven COP	Verdict
LDO at ₹107.65 per litre	0.67	Beaten by any working machine
PNG at ₹68 per SCM, Gujarat industrial	1.17	Beaten by any working machine
Furnace oil at ₹71.99 per kg	1.10	Beaten by any working machine
Electric resistance	Just under 1	A heat pump moves heat instead of making it, so it wins on every unit

Breakeven COP is the efficiency at which the heat pump exactly matches what the incumbent costs to run. We compute it at the Maharashtra HT-I energy charge of ₹8.44 per kVAh. Anything above the breakeven is margin. The full comparison against each boiler type sets out the method, and the savings calculator runs it on your own tariff and draw.

Accelerated depreciation at 40% applies to heat pumps, which are named explicitly in the Income Tax rules. That is a real effect on the post-tax cost of the asset and it is worth taking to your finance team early.

What about Legionella and storage temperature?

Stored hot water has to be held hot enough that the store is not a culture. That is why the store runs at the top of the 45 to 70°C guest band. Delivery is then blended down at the point of use.

So delivery temperature becomes a purchasing criterion. Low-cost air source equipment that struggles above 55°C forces an electric booster into the circuit to hold the store. The booster runs on resistance heating. That erodes exactly the saving the project was bought for. A machine with continuous output to 120°C holds the top of the band without assistance.

Ask any supplier what output temperature the machine holds continuously, at the source temperature your site has. Ask for that figure in the hottest and coldest weeks of the year. A rated figure at a favourable operating point is not an answer to that question.

Coastal properties need a metallurgy conversation

Goa, Kochi, Chennai and Mumbai properties sit in salt air, and salt air is hard on an outdoor coil. It is handled in the specification. Coil metallurgy and coating, fin spacing, and a defined cleaning interval are all decided at design. Fouling is the slower problem and the more expensive one. A fouled exchanger raises no fault that anyone reports. It appears only as a gently falling coefficient of performance.

What to do next

Get a week of hot water draw off the meter. Record the inlet temperature at the coldest point of the year, and the shape of the morning peak. Those three produce a specification that can be quoted against, and they take a week to collect.

With them in hand, the sizing guide shows the arithmetic, and the savings calculator puts a running cost against it. The maintenance programmes set out what the machine needs once it is in. The full temperature envelope covers what the equipment delivers and where it stops. When the numbers are ready, send them to us.