How much energy does raising the aircon by 1 degree save?

In tropical climates, raising the setpoint by 1 degree Celsius typically saves 6–10% of aircon electricity consumption, according to Celsius-native HVAC industry sources. The US Department of Energy cites 3% per Fahrenheit degree, which converts to roughly 5.4% per Celsius degree — consistent with the lower end of that range.

Why do some sources say 3% and others say 10% per degree?

The discrepancy has several causes: different temperature units (Fahrenheit vs Celsius), different starting temperatures, different climate conditions, and whether the figure refers to cooling energy only or total electricity. A 3% per Fahrenheit figure becomes roughly 5.4% per Celsius degree. Sources measuring at warmer outdoor temperatures (tropical) tend to produce higher savings estimates per degree than those measured in temperate conditions.

The Science · Aircon Energy Savings

Why Do Different Sources Cite 3–11% Savings Per Degree?

If you've looked into aircon energy savings, you've seen wildly different per-degree figures. A Singapore technician says 9–11%. A Philippine government source says 6–8%. The US DOE implies about 5%. Here's why, and which figure to use.

Applies across the tropics: Singapore, Kuala Lumpur, Jakarta, Bangkok, Manila, Ho Chi Minh City, Mumbai — and why tropical climates specifically tend toward the higher end.

The sources and what they actually say

Source	Cited figure	Temperature unit	Context
US Department of Energy	~3%/°F	Fahrenheit	US temperate climate homes, cooling season
Philippine Dept. of Energy	6–8%/°C	Celsius	Tropical, per degree below 25°C
Sky Blue Aircon (Singapore)	9–11%/°C	Celsius	Singapore HVAC practice
DLCuration (Singapore)	3–5%/°C	Celsius	General Singapore guidance
Mr. Aircon Philippines	6–8%/°C	Celsius	Philippine households, per DOE citation

Reason 1: Fahrenheit vs. Celsius conversion

The US DOE's ~3% per degree Fahrenheit converts to approximately 5.4% per degree Celsius (since 1°C = 1.8°F, and 3% × 1.8 ≈ 5.4%). This alone eliminates much of the apparent gap between US figures and tropical-market figures. The DOE figure is frequently misquoted as "3% per degree" without specifying Fahrenheit, which leads people to underestimate the Celsius-equivalent saving.

Reason 2: Climate conditions

The savings per degree depend on the difference between outdoor and indoor temperature. In a tropical climate, the outdoor temperature is often 30–34°C. Dropping your setpoint from 26°C to 25°C forces the unit to maintain a larger gap against a hot outdoor environment, requiring proportionally more compressor work than the same change in a temperate climate where outdoor temperature might be 22°C. This is why tropical-market sources consistently cite higher per-degree figures than temperate-market sources.

Reason 3: What "savings" is measured relative to

Some sources measure savings relative to the unit's energy use at a specific baseline temperature. Others measure relative to total household electricity. A 10% reduction in aircon-only consumption translates to roughly 3–6% of total household consumption if aircon represents 30–60% of the bill. This accounting difference can make the same physical saving look like a very different percentage depending on how the study frames it.

Reason 4: Starting temperature matters

The per-degree saving is not perfectly linear. The gain from going from 18°C to 19°C (already very cold, large gap to outdoor temperature) is larger in absolute energy terms than going from 25°C to 26°C (closer to ambient). Studies that measure the saving starting at 18°C will show higher per-degree figures than studies starting at 25°C.

Which figure should you use?

For tropical Asia — Singapore, Malaysia, Thailand, the Philippines, Indonesia, India — 6–10% per degree Celsius is the most applicable range. It is directly cited by the Philippine Department of Energy for exactly this context, consistent with the Celsius-converted DOE figure, and aligns with Singapore HVAC practitioner guidance. The 9–11% figures from some Singapore sources may be measured from lower starting setpoints (e.g. 18°C or 20°C baselines) where the gain per degree is larger.

Our calculator uses a temperature multiplier table derived from HVAC industry consensus (approximately 7% per degree in the 22°C–26°C range) rather than a single flat percentage, since the relationship is not perfectly linear. The 6–10% range is appropriate as a rule-of-thumb for explaining the mechanism; the table provides more precise estimates for each specific temperature step.

The practical takeaway: whether the true figure is 6% or 10% per degree, the direction is unambiguous and the magnitude is meaningful. Raising your setpoint from 22°C to 26°C — four degrees — represents a saving of roughly 24% by our model, and somewhere between 24% and 40% depending on which per-degree figure applies to your specific unit and climate. Either way, it is the single largest available lever that costs nothing and changes nothing about comfort.

See the exact savings for your temperature setting →

The calculator uses a per-step multiplier table, not a flat %

Sources

U.S. Department of Energy — ceiling fan and thermostat guidance — implies ~3% per °F saving for cooling, the basis for the ~5.4%/°C converted figure.
Mr. Aircon Philippines — citing Philippine Department of Energy — each degree Celsius below 25°C increases electricity consumption by 6–8%.
Sky Blue Aircon Singapore — cites 9–11% saving per degree Celsius from HVAC practice in Singapore conditions.
DLCuration Singapore — cites 3–5% per degree, reflecting a more conservative estimate at moderate starting temperatures.
Teko.ph Philippines — Meralco recommends 24–25°C for comfortable and energy-efficient cooling, consistent with 6–8%/°C Philippine DoE guidance.

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