roll 150x150 DIY: Insulating Your AquariumDepending on your level of obsession in the hobby, heating your aquarium(s) is a cost that can quickly add up on a monthly basis.  Unfortunately, glass and acrylic are not the best insulators but are necessary to be able to see into your tank.  Assuming you’re not simply heating the whole room to 75+ degrees, insulating your tanks is a cost-effective solution to keep those aquatic heating bills down so that you can spend more of that disposable income on other areas of the hobby that are less boring.

This is a simple DIY that can save you a lot of money.  Lining the surfaces of your aquarium with insulation, you can cut down considerably on your electricity use from your heater. Glass is not the greatest insulator; therefore, much of the heat we pay to put into our aquariums is leaving through every surface.  This is especially noticeable if the room temperature is even just a few degrees cooler than your aquarium’s temperature.  The heat is drawn from your aquarium as the cooler air outside the aquarium circulates around the glass. Any barrier between the aquarium water and cooler air will help stabilize the temperature.

Your glass or acrylic is the first insulator.  An aquarium background can be another insulator.  Much like layering clothing to keep warm in cold weather, layering materials outside your aquarium will keep the temperature from fluctuating.  Different materials will have different insulating properties.  For this project we chose to use a product called Reflectix.  This is a general purpose insulator that is traditionally used to insulate ducts, walls, roofs, etc.  When used for a water heater, it has an “R-value” of 4.5.  “R-Value” is a measurement of heat resistance.  Depending on the thickness of your glass, you probably have an “R-Value” of about 0.2 on your aquarium. Many people use foam board insulation as well – it has an R value of 4.5-5.0 per inch of thickness.  The advantage of Reflectix is that it is much more slim line and easy to work with.

This upgrade will be most noticeable if you have a set-up that many aquariums and even more noticeable if said aquariums are kept in a garage or basement where the room temperature is usually much lower than the aquarium temp.  The most practical application is for those that have multiple tanks set-up for breeding, where the necessity to see into the tank is more functional than aesthetic.  However, it can be used on an aquarium in your living room.  For this application you’d first line the walls with an aquarium background, and then apply the Reflectix to the outside of the background.  Some enjoy the space age look of the silver finish in their fish rooms.

Tools needed:

  • Hot glue gun or 3M packing tape
  • A roll of Reflectix (found at Home Depot and Lowes.)
  • Razor knife or Scissors


Step one: Pick your aquarium. This project is a lot easier if the aquarium is empty.  It can be done when full with some extra effort.aquarium3 DIY: Insulating Your Aquarium

Step Two: Unroll your roll of Reflectix.  Line it up with one of the sides of your aquarium.
reflectix DIY: Insulating Your Aquarium

Step Three: Use the edge of the aquarium to guide your razor knife; cutting a piece to fit one side.cutting DIY: Insulating Your Aquarium

Step Four: Lay a bead of hot glue along the top trim of your aquarium.
glue1 DIY: Insulating Your Aquarium

Step Five: Apply pressure while the hot glue sets. Then repeat the process for the bottom trim.
pressure DIY: Insulating Your Aquarium

Step Six: Repeat steps 3 through 5 for the back and other side.

Step Seven: Insulate the bottom using any scrap pieces. If you have no scraps you usually have to put two pieces together to cover the bottom.
bottom DIY: Insulating Your Aquarium

Step Eight: Enjoy the electricity savings. In this fry raising tank we’ve covered 3 sides and the bottom in Reflectix.
finished DIY: Insulating Your Aquarium

This has helped lower our fish room’s electricity bill.  Total cost for each 20 gallon aquarium retrofitted with Reflectix on 3 sides and bottom is about $4 – savings that are easily recouped in less than a year.

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