Let’s take a look at your aquarium and analyze where we can save energy and improve the overall efficiency. The main aspects of an aquarium that can be changed or controlled to save on your energy bill are as follows:
- Lighting: light sources & using a schedule
- Heater / cooler: save money in the long run
- Pump: needs more energy than you might think
- Insulation: let’s calculate what it costs
1. Don’t have your lights on all the time
Let’s start with the lighting of your aquarium, one of the areas of the aquarium where we can save quite some energy. Did you know that choosing the right light source is key? Many aquarists prefer fluorescent lighting, because it provides aquariums with the best colour and is affordable. Over the years, however, LED lighting has improved, become cheaper and most importantly, energy efficient! Although the initial costs of LED lights are a little higher, you can easily recoup these costs, since LED’s last longer and are much more efficient, 40 – 90% compared to fluorescent lights!
But changing your lights isn’t the only thing you can do to reduce energy. We also advise you to look into your biotope’s needs, because you can choose to decrease the amount of time your lights are on. If your aquarium doesn’t need 12 hours of light per day, you can for example use a timer switch to set a schedule. With most LED’s you can also do an intensity schedule, allowing you to save energy in a different way. You do not need to run LEDs at 100% capacity all day long, but you can have a more realistic and energy saving sunrise and sunset schedule. It creates a more natural and better environment for your fish and at the same time save you a few bucks.
2. Replace the heater / cooler
Getting the right heating or cooling equipment is also important. Cheap yet low quality equipment will save your initial costs but costs you more in the long run if it consumes more energy than high quality parts. It is good to know between which temperature boundaries your fish and plants thrive. Some coldwater fish may not even need a heating or cooling system! In general, slowly turning down the heat in your aquarium by 1 or 2 degrees Celsius won’t hurt your fish and will save you a lot of energy costs. Just don’t overdo it, make sure the fish are still comfortable. It is your responsibility as a hobbyist to keep your fish at reasonable temperatures. Another advantage of maintaining a lower temperature is that your fish’s metabolism slows down. This means your fish need less food and thus saves you on your monthly food costs.
3. Get an energy efficient pump
So how about your pump? The filter pump runs day and night, so saving energy costs on water flow is simply done by buying the most energy efficient pump considering your aquarium. If you work with multiple pumps, you don’t need to turn all flow pumps on at the same time. Put them on a timer for a more natural change in water flow, which also saves you some energy costs. Use different time schedules for different pumps. But do not forget to keep your filter always on.
4. Insulate the aquarium
Next topic, insulation! Let’s start with insulation in general: there are many options to insulate your aquarium. Amongst recommendations are reflective foil or Styrofoam., but this list is non exhaustive if you are creative and have access to many materials.
About seasons then: winter. The more areas you can insulate, the more you keep the heat inside your aquarium. But to understand this concept, we first need to understand what heat loss is. Heat naturally flows from warm to cold. Heat loss is driven by temperature difference (in physics this is depicted by ∆T = Taquarium_- Troom). The higher ∆T is, the faster the aquarium loses heat. In other words, the bigger the temperature difference is between your aquarium and the room, the more important it is to insulate your aquarium properly.
Let’s move on to summer: the same reasoning as before holds, except this time Troom is higher than Taquarium. In this case the insulation material will prevent heat from flowing into your aquarium (instead of out as in the previous example). We know it is less likely that you’ll have to prevent heat from entering your system, however note that it can be limited if you are one of those cases. It applies to you if you have a cooling system to control your aquarium’s temperature.
Let’s move on to the top of the aquarium. You can use insulation to prevent water vapor from escaping your aquarium. Especially a tight, thick (glass) lid on top of the aquarium can prevent unnecessary energy loss. You may wonder why this is important. This has to do with the energy that goes into water molecules when they evaporate from the liquid into the vapor phase. We all know that we sweat when we feel hot and that we cool down when we are wet but what’s the science behind this? Hold tight, because for this explanation we dive into the nature of molecules. If you are not interested in the physics or chemistry behind this, you can skip this part, we promise we won’t hold a grudge.
The specific heat capacity (cp) of water is 4,184 kilojoule per kilogram per kelvin [KJ ⋅ kg−1 ⋅ K−1], which is the amount of energy (J) you need for a kilogram of water to increase one degree in Kelvin or Celsius. The heat of vaporization of water at 25 °C is 2442 KJ/kg and is a good approximate number to make estimations in the temperature range of 20 – 30 °C (at which most, if not all aquaria operate). The density of water at 25 °C is 0,997 kg/L which is roughly 1 kg/L. If you do the math, you can see how much energy it costs to vaporize 10 liters of compared to heating up 10 liters of tap water to an average Taquarium (25 °C), assuming tap water is about 12 °C.
|Vaporizing 10 liters of water
|2442 (KJ/kg) ⋅ 10
|Heating 10 liters of water
(from 12 to 25 °C)
|4,184 (KJ/kg) ⋅ 10 ⋅ (25 – 12 °C) = 4,184 ⋅ 10 ⋅ 13
The difference in magnitude of these numbers illustrates how much energy is required to vaporize water compared to heating it or even keeping it at a constant temperature. Therefore, we highly recommend you prevent water vapor (and the energy it holds) escaping from your system by insulating the roof of your little friends. This is because water vapor releases its ‘phase’ energy to the surface it sticks to after condensation. The water droplets hanging on the roof inside your aquarium have released their 2442 KJ/kg to the upper wall. By insulating this upper wall, you keep this energy inside your system as best as possible!
All of this advice is great, but you didn’t start your aquarium to wrap it in, looking like a mummy. An aquarium should remain an eye catcher, so instead of insulting your aquarium (see what we did there😏), you can insulate it in a clever way (disclaimer: this probably takes more effort)! You can keep it simple and solely prevent energy losses, or you can insulate in a creative manner. It is up to you, but we would like to present some ideas. Instead of using reflective foil or Styrofoam, you could also choose to install mirrors (reflecting from out to in) which gives your aquarium more depth. When you look inside your aquarium it will look bigger, with more fish and plants instead of insulation material. On the back of the mirrors you can place the most efficient insulation material you can find; it will not be visible inside the tank itself. Please test and see if mirrors suit your aquarium, it strongly depends on the way your biotope looks. Not all walls may be suitable for mirrors either. If you don’t want to or can’t work with mirrors, you could also make use of some nice background posters.
There are quite some areas where savings can be made. Take a look at your lighting, heater & cooler and pump and you’ll see that replacing some of these parts can make a difference! Also don’t forget about insulation, since it can really help reducing heat loss.
Keeping fish is a beautiful hobby and by providing you with these tips, we hope we can keep it affordable as well. Hopefully these tips can help you to minimize your energy costs. Not only because you save money yourself in the long run: being as sustainable as possible benefits the entire world! Every step, even if small, helps for the transition into a sustainable economy.
Do you have other suggestions? Leave your tips and tricks down below in the comments!