Aquarium Electricity Consumption Calculator Singapore: kWh Per Month

Working out what an aquarium adds to an SP Group bill is a matter of multiplying wattage by hours and dividing by 1000. That formula hides real complexity because several devices cycle, not run continuously, and chiller duty depends on room temperature. This aquarium electricity consumption calculator Singapore guide from Gensou Aquascaping at 5 Everton Park gives you the formulas, realistic duty-cycle estimates for each device type, and worked examples with current SP Group tariffs. Use these to predict a bill before you buy the gear.

Quick Facts

• SP Group electricity tariff early 2026: 29.80 cents per kWh (inclusive of GST)
• Base formula: (Watts multiplied by hours per day multiplied by 30) divided by 1000 = kWh per month
• Continuous devices: filter pumps, powerheads, air pumps
• Cycled devices: chillers (20-40 per cent duty), heaters (5-25 per cent duty)
• Scheduled devices: lights, UV, CO2 solenoid
• Typical Singapore nano reef (100 L): 50-65 kWh per month
• Typical Singapore planted tank (80 L): 14-18 kWh per month

The Core Formula

Energy used by any device = Watts x hours x days, divided by 1000 to convert to kilowatt-hours. A 30 W light running 8 hours a day for 30 days: 30 x 8 x 30 / 1000 = 7.2 kWh. Multiply by 0.298 for the SGD cost at current tariff: 7.2 x 0.298 = $2.15 a month. The only ambiguity is in devices that do not run at their rated wattage all the time; heaters and chillers cycle based on temperature, so effective consumption is the rated watts times duty cycle times hours.

Measuring Actual Wattage

The number printed on the device is often the maximum, not the average. A smart plug such as a TP-Link Tapo P110 reports real draw in watts and logs kWh over time. Retail price at Shopee and Lazada is $15-22. Plug each piece of equipment through it for a week and you have exact numbers. Particularly revealing for old pumps whose rated watts no longer reflect aged motor efficiency, and for LED drivers which often draw 70-85 per cent of the rated figure.

Chiller Duty Cycle

A chiller rated 200 W does not consume 200 W continuously. It cycles on when water temperature exceeds the setpoint, off once the setpoint is restored. In a well-insulated 100 litre tank in an air-conditioned room at 25 degC, a chiller set to 24 degC might run 20 per cent of the time. In a hot HDB living room at 31 degC with the chiller targeting 24 degC for a reef, duty cycle climbs to 35-45 per cent. Formula: 200 W x 24 h x 30 x 0.35 / 1000 = 50.4 kWh, which is $15 monthly just for the chiller.

Heater Duty Cycle

Most Singapore tanks do not need heaters. When one is used, for species requiring 28-30 degC in an air-conditioned bedroom, duty cycle is usually 10-20 per cent. A 100 W heater at 15 per cent duty: 100 x 24 x 30 x 0.15 / 1000 = 10.8 kWh, which is $3.22 monthly. Thermostats fail; a heater stuck on draws full watts continuously and the monthly cost multiplies by five while potentially cooking the fish.

Filter Pumps and Powerheads

Canister filters and return pumps run 24/7, so the calculation is straightforward. A 25 W canister: 25 x 24 x 30 / 1000 = 18 kWh = $5.37 monthly. A 10 W powerhead: 7.2 kWh = $2.15. Air pumps are usually 3-6 W; a 4 W pump costs 86 cents a month. DC pumps at lower throttle settings, common on modern reef returns, can save 30-50 per cent over equivalent AC pumps but usually cost more upfront.

Lighting Calculations

Lighting duration is scheduled, typically 6-10 hours for planted and reef tanks. A 50 W LED at 8 hours: 12 kWh = $3.58 monthly. A 150 W reef light at full output for 6 hours: 27 kWh = $8.05. Programmable drivers that ramp up and down average around 60-75 per cent of peak draw over the photoperiod, which most calculators miss. Use the smart-plug method for accurate numbers on dimmed or programmed lights.

Worked Example: 60 cm Planted

Light 30 W x 8 h = 7.2 kWh. Canister 10 W x 24 h = 7.2 kWh. CO2 solenoid 5 W x 8 h = 1.2 kWh. Total 15.6 kWh at 29.8 cents = $4.65. Over a year that is $55.80. Low enough that the tank itself is a rounding error on most household SP bills. Double the light wattage for high-tech carpet growth and add 15 kWh monthly, or $4.47.

Worked Example: Nano Reef 60 cm

LED 50 W average x 8 h = 12 kWh. Return pump 15 W x 24 h = 10.8 kWh. Powerhead 10 W x 24 h = 7.2 kWh. Skimmer 8 W x 24 h = 5.76 kWh. Chiller 100 W at 30 per cent duty x 24 h = 21.6 kWh. Total 57.4 kWh at 29.8 cents = $17.10. Chiller alone is 37 per cent of the bill, which is why insulation and ambient management pay off.

Worked Example: 120 cm Community

Lights 100 W x 10 h = 30 kWh. Canister 25 W x 24 h = 18 kWh. Air pump 4 W x 24 h = 2.88 kWh. UV 18 W x 6 h = 3.24 kWh. Total 54.12 kWh at 29.8 cents = $16.13 monthly. A larger freshwater community tank costs similar to a nano reef at the electricity line because the absence of a chiller offsets the doubled light.

Related Reading

• Aquarium Electricity Cost Calculator Singapore
• Aquarium Electricity Cost Singapore
• How to Reduce Aquarium Electricity Bill Singapore
• Best Electricity Plan for Aquarium Singapore
• Best Aquarium Chiller Singapore