The problem: Guests in warm-climate holiday rentals routinely set AC to 16–18°C. They are not trying to keep the room at 16°C, they want to cool down quickly and press the lowest button available.
What we found: Setting AC to 16°C versus 24°C is not a marginal difference. At 16°C, a split unit uses up to 70% more electricity. The temperature guests choose when they first arrive, hot, frustrated, pressing the remote, determines the electricity cost for the entire stay if nobody adjusts it.
What it means in euros: A single-degree change in average setpoint across a season has a measurable impact on electricity costs. Preventing extreme setpoints, not eliminating AC, not restricting comfort, recovers €190–450 per unit per season.
Guests who set 16°C can increase AC energy use by up to 70% compared to a 24°C setting. That single number explains a large part of why AC electricity bills are high in warm-climate rentals, and why the solution does not involve asking guests to be more careful.
What temperature do guests actually set AC to?
In warm-climate holiday rentals, Mediterranean villas, beach apartments, island properties, guests arriving after a day in the heat consistently press the remote to its lowest available setting. That setting is usually 16°C or 18°C, depending on the unit. A minority will set 20°C. Very few set 24°C or higher on arrival.
This is not random. It follows a predictable pattern driven by the conditions at arrival:
- Guests arrive overheated from outdoor temperatures of 30–38°C
- They want relief immediately, not after 40 minutes of gradual cooling
- The remote offers a temperature range; pressing the bottom feels like the fastest route to comfort
- Nobody explains that 16°C and 24°C will both cool the room, just at different speeds
The setting chosen in the first five minutes of arrival often persists for the rest of the stay. Guests cool off, fall asleep, go out, and the unit keeps running at whatever was set.
Why 16°C costs so much more than 24°C
The relationship between setpoint temperature and electricity consumption is not linear. As the target temperature drops further below ambient, the split unit must work progressively harder to maintain the differential. EU and IEA building energy modelling quantifies this: a split unit set to 16°C in a room with 28°C ambient temperature uses up to 70% more electricity than the same unit set to 24°C.
That 70% gap exists before accounting for runtime. If a guest sets 16°C and leaves the unit running for 12 hours, the electricity cost is not just 70% higher per hour, it is 70% higher across every hour the unit runs at that setting. The two factors compound.
The temperature guests think they need vs the temperature they actually need
For comfortable sleep, the standard guidance is 18–21°C. For comfortable indoor activity in a warm climate, 22–24°C is the typical range used in commercial buildings, hotels, and offices. Neither of these requires 16°C.
Guests who set 16°C do not want a 16°C room. They want to cool down from 35°C outside. Once the room reaches 22°C, they are comfortable, the AC keeps cooling to 16°C anyway, because no one adjusted it.
The gap between what guests set and what they need is the gap operators pay for. A minimum temperature limit of 21°C eliminates the most expensive setpoints without restricting comfort during normal use.
Does setting a minimum temperature affect guest satisfaction?
This is the question operators ask most. The answer, based on operational experience across multiple Mediterranean rental seasons, is no, when done correctly.
A minimum of 21°C still allows guests to cool a room from 30°C to 21°C. That is a 9-degree drop, which delivers strong cooling effect. Guests who want a cool room get a cool room. What they do not get is the unit continuing to run at 16°C after the room is already cool.
The properties where operators report no impact on reviews are those where the minimum is set at 21°C or higher. Properties that try to limit cooling to 24°C occasionally generate complaints from guests arriving in peak summer heat. The 21°C threshold has consistently produced no guest friction.
The setpoint problem is not solvable through communication
Operators who post notes near the AC, include guidance in the welcome book, or send messages at check-in asking guests to use AC responsibly see minimal impact on setpoints. Guests read those messages once, if at all. When they arrive hot and reach for the remote, the message is not in their active memory.
Smart thermostats do not reliably solve this either. Guests who find a smart thermostat limiting their cooling override the settings, or the thermostat requires a WiFi connection and a guest-facing app that adds friction without guaranteeing compliance.
The setpoint problem is a hardware problem. It requires a hardware solution. A device that physically prevents the AC remote from transmitting commands below a set temperature is the only reliable intervention.
- Guests in warm-climate rentals consistently set AC to 16–18°C on arrival, not because they need 16°C, but because they want fast cooling from peak summer heat
- Guests who set 16°C can increase AC energy use by up to 70% compared to a 24°C setting (IEA/EU data)
- The temperature set in the first five minutes of arrival often persists for the entire stay, the cost compounds over hours and days
- A minimum limit of 21°C eliminates the most expensive setpoints without restricting meaningful comfort, guests can still cool from 30°C to 21°C
- Communication-based approaches (welcome book, messages, signs) do not reliably change arrival setpoints
- Only a hardware solution, a device that intercepts remote commands below the minimum, solves the setpoint problem reliably
When Narveo is not the right solution
Narveo solves the setpoint problem in warm-climate rentals with split AC systems. It is not suited to ducted or centralised systems, cool-climate properties where guests rarely use AC, or owner-occupied properties. If guests in your property consistently set reasonable temperatures without instruction, the setpoint problem does not apply and the return will be lower.
Set the floor. Let guests control the rest.
Narveo prevents AC commands below your minimum temperature. Guests keep full access to cooling above that floor. No app. No WiFi. No installation. €69 per unit.
Order now – €69