How Much Energy Does My Aquarium Use?

By Vernon Trollinger, August 9, 2016, Energy Efficiency

Saving energy (and money) is always easier when you know how much you’re using. But because many of the convenient smaller appliances we use seem to draw little amounts of power, we all too often discount how their use really does impact our electricity bills. With our How Much Energy Does This Appliance Use?, we’ll examine what’s watt in small appliances to see approximately how much they use. To help you understand very basic electrical consumption calculations, you’ll need to keep a simple equation in mind: Volts (V) x Amperes (I) = Watts (W). What you’ll discover is how just how small appliances can contribute to your home’s energy usage and how these little conveniences can make big differences on your bill.

How Much Energy Does My Aquarium Use?

How Much Energy Does My Aquarium Use? | Bounce Energy Blog

On this deep dive into world of fin-fanciers, we’re going to submerge ourselves in aquarium energy use. Because fish tanks are self-contained environments, maintaining their life support system on dry land — round the clock, year ’round — can eat up a significant chunk of energy.

Three factors affect an aquarium’s energy use:

  1. The size of the tank;
  2. The kind of fish and their environmental needs; and
  3. Whether there are plants in the tank.

The average sized aquarium is roughly 29 gallons to 30 gallons, making it about 30” long x 12” wide x 18” deep. Different fish have different habitat needs – for example, fresh water tends to have more oxygen dissolved in it versus salt water . Consequently, salt water aquariums have slightly different water filtration, circulation, and maintenance needs to keep those fish thriving. Plants make the aquarium environment more interesting and healthy for the fish, but the plants require the right amount of lighting in order to thrive as well.

To prevent this introductory discussion from becoming too complex, we will stick to the average medium tank size of 30 gallons. To keep our fish happy and healthy, we need to make sure that water is clean, aerated, and kept at the right temperature 24/7. That means we need the right kind of pump.

Pumps — Going with the Flow

How Much Energy Does My Aquarium Use? | Bounce Energy Blog

There are two basic kinds of pumps: air and water. Both are used to help move water through a filter and to circulate the water for aeration.

Air pumps make bubbles that float to the surface and move the water. Moving surface water constantly mixes air and brings oxygen into the water. Air pumps might be a great solution for small tanks, but in larger tanks, over 18-24 inches, resistance to air pressure makes the air pump use more energy. In terms of energy use, an air pump wattage runs about 3 watts. Larger aquariums (and some ponds) >50 gallons using larger air pumps will run about 6 watts.

Water pumps (including power heads) create currents and aeration, while moving water through various peripherals like filters, skimmers, and heaters. What determines the pump you need is the volume of water you need moved. Generally, about 6 gallons per hour is the recommended filtration rate; thus, if you have a 40-gallon tank, use a pump that moves about 240 gallons per hour (gph). In our case, we’re looking for a pump for a 30-gallon tank that can move at least 180 gph.

How Much Energy Does My Aquarium Use? | Bounce Energy Blog

Submersible pumps can be submerged, but while this is handy, some submersible filter pumps don’t generate the waves we need for aeration. In that case, we would also want to wave pump to help aerate and circulate the water. Inline pumps are outside the tank. Far more powerful than submersible pumps, these are connected via tubing to filters, heaters, chillers, etc. There is also the pump-filter combo that hangs on the side of the tank pumping water through filter and uses a venturi to mix air and water to create the surface turbulence that aerates the water.

Because water is heavier, water pumps require more robust motors. Water pumps that fit with in the flow rate for our 30-gallon tank include:

Heaters, UV Sterilizers, and Lighting

How Much Energy Does My Aquarium Use? | Bounce Energy Blog

Water heaters help keep water at the proper temperature, 72° F to 82° F (depending on the fish type), with a minimum fluctuation of 1-2 degrees over a 24-hour period. A rule of thumb is that it takes 3-5 watts per gallon to maintain water temperature depending on the room’s ambient temperature. Naturally, the lower the room’s ambient temperature, the more heat the aquarium requires and the higher the wattage.

If our room is at 68°F, it will take 102 watts to keep per day to keep the 30-gallon tank heated at 72° F. To keep it heated to 82° F, it will need 170 watts a day. We’re going to stay with 72° F, but since we want a little cushion for power, we’ll choose an Aquatop Quartz 150 Watt heater.

UV sterilization lamps come after the filtration section. These kill all sorts of free-floating green water algae, parasites, and harmful bacteria. Lamp wattage depends on tank size and flow rate. In our case, we’re looking at one rated between 3 watts to 9 watts, as the UV lamp runs continuously.

Lighting can be an energy headache depending on the wattage. A basic T8 fluorescent lamp uses from 17 to 24 watts depending on the color temperature and lumen output. If you plan on having plants or corals, you want to be able to provide enough light to keep them growing and healthy — whilch will require better-quality lighting and keeping the lights on for 8 to 12 hours per day.

A good rule of thumb is 2-5 watts per aquarium gallon, but this also depends on the needs of your plants. The deeper the tank, the brighter the lamps will need to be and the higher wattage it will require. These lights usually have a higher lumen output and, depending on the bulb type (halogen, fluorescent, or LED ), they can put out LOTS of heat — which may require using a fan or water chiller to keep the water at the proper temperature. We’ve got a couple of plants in our tank, but with a somewhat shallow (18”) tank, so we’ll go with a 20-watt T8 fluorescent.

All Those Details are Great, but What Does It All Really Cost?

How Much Energy Does My Aquarium Use? | Bounce Energy Blog

Good question! Let’s start by assuming we’re on fixed-rate electricity plan paying is 10¢/kWh.

Our pump is going to be the Danner Supreme Aqua-Mag 190 ghr running at 19 watts. It’s powerful enough to move the water and still provide adequate flow rate for the filter and UV lamp. Since 19 watts/hour x 24 = .456 kWh/day, this becomes 13.68 kWh/month and 164.16 kWh/year for a cost of $16.42/year.

As mentioned, we’re going with the Aquatop Quartz 150 Watt heater. This becomes 150 watt/hour x 24 =3.6 kWh, 108 kWh/month, and 1,296 kWh/year for a cost of $129.60.

Our UV lamp requires 5 watts. This means 5 watts/hour x 24 hours = .12 kWh/day, .36 kWh/month, and 43.2 kWh/ year for a cost of $4.32/year.

Lighting will come from a standard 2- watt T8 fluorescent. A cheap timer can help reduce the energy consumption, so we’ll estimate that the lights are on 66% of the time or 16 hours of the day. 20 watts/hour x 16 hours = .32 kWh/ day, 9.6 kWh/month, and 115.2 kWh/year for a cost of $11.52.

Total estimate yearly electricity consumption = 1641.6 kWh/year totaling $164.14 a year.

The main energy thief here is obviously the heater. A similar estimate for a 30-gallon tank without a heater put the energy usage between about 150 – 200 kWh/year – or $15 to $20 per year. But also remember that your choice of fish and how you design their environment that will make the biggest splash in your wallet.

Big energy bills tangling your finances? Don’t let that crimp your style! Stay tuned for the next installment of our How Much Energy Does This Appliance Use? series when we show you how to comb out the high costs of blow dryers and other beauty accessories!

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A native of Wyomissing Hills, PA, Vernon Trollinger studied writing and film at the University of Iowa, later earning his MA in writing there as well. Following a decade of digging in CRM archaeology, he now writes about green energy technology, home energy efficiency, DIY projects, the natural gas industry, and the electrical grid.

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