Introduction: LED Fireplace Insert

About: Husband. Father. Artist. Musician. Teacher.

We have a wood burning fireplace in our home that hasn’t been utilized in decades. The previous homeowners planned on refitting the fireplace with a natural gas insert but were turned off by the price.

As this Canadian winter sinks its knobbly icicle teeth into the new decade, I yearn for the warm flickering glow of a traditional hearth. As our home is small and centrally heated, a real fire/gas insert would merely produce an unnecessary amount of additional heat. A no-heat solution was also a requirement as I wanted to keep the fireplace pet friendly and safe for small children.

Since I’m only really after the coziness produced by the GLOW of a real fire and not the heat, I set out to create a battery powered LED insert that required no programming and was simple to install and remove. The solution came in the form of those relatively newfangled LED Flame Bulbs! This is a simple project that can be completed at a leisurely pace on a cold Sunday afternoon.




  • LED Flame Bulb (x3)
  • Foam Board
  • AA Battery Pack
  • SPST or S Toggle Switch
  • Heat Shrink Tubing
  • Double Sided Tape
  • Length of Double Wire (Speaker Wire or other)


  • Utility Knife
  • Steel Rule
  • Soldering Iron + Solder (or Wire Nuts)
  • Wire Strippers
  • Side Cutters
  • Small Flat Head Screwdriver

Step 1: Measure and Design

Our sooty fireplace hasn’t been cleaned out since its last fire (circa 1960 ) and is filled with ashes, as well as, a steel grate for holding logs off the floor of the firebox while they burn. I decided to utilize this steel grate for the LED conversion and took rough measurements of its footprint.

I also decided NOT to clean the fireplace; adding to the overall realism of the insert. What’s great about this approach is that it can be applied to any wood-burning fireplace without any modification. The measurements I came up with were 11” x 5”. From there, I began to design the insert. I decided to use magnets to attach the insert to the underside of the grate. I decided to make the insert battery powered and decided on the placement of the ON/OFF switch.

Step 2: Disassembling the LED Flame Bulbs (A)

As the insert will be battery powered, we won’t need the E26 connector end of the bulb (E26 = standard light bulb connectorin North America ), nor the voltage converter circuit, nor any other part of the plastic housing. All that we’re after, is the flexible LED circuit which is populated with surface mount components, a tilt switch, and two power leads.

To disassemble the bulb, use a small flat head screwdriver to separate the E26 connector end of the bulb from the plastic diffusion bulb cover. Once it’s separated, clip the power leads coming off of the voltage converter circuit board (red and black wires ). This will free both halves of the bulb.

Step 3: Disassembling the LED Flame Bulbs (B)

Next, separate the plastic diffusion bulb cover from the internal support piece that holds the flexible LED circuit, using the same small flat head screwdriver. If you find that the screwdriver head is too girthy to separate the two pieces, use a utility knife to start the separation of the two pieces until the screwdriver’s head can be inserted between the two pieces to separate them.

Step 4: Disassembling the LED Flame Bulbs (C)

Once the flexible circuit has been exposed, use a soldering iron to de-solder the connection points holding both ends of the circuit together. If you do not have access to a soldering iron, carefully use a hobby knife to do this. Then, CAREFULLY pry off the flexible circuit board from its plastic holder and set the remaining plastic piece aside with the rest of bulb pieces. (I always save these types of pieces for future projects; they end up in a container I call the “bin of potential” ! ) Test the circuit with two AA batteries to make sure that it wasn't damaged during the removal process.

Congrats! You have successfully isolated the circuit! Now, repeat this process twice more!

Step 5: ​Prepping the Base of the Insert

Choose a strong, lightweight material to use as a base for the three circuit boards and AA battery holder. I chose to use one of my go-to materials which every maker should keep in stock: foam core (foam board). Cut the foam core to size, using multiple shallow passes with a fresh bladed utility knife against a steel rule. Next, use double sided tape to affix the flexible LED circuits to the foam core. Leave roughly a ½” space around the perimeter of LED circuits as you place all three circuits tightly together in row.

Step 6: Assembling the Circuit

*I’ll be using a soldering iron for this next step, but an effective alternative is to use small wire nuts to make all the necessary connections. Use what you have on hand or have access to !

Start soldering the boards together by soldering all the positive leads together (red wires ), then all the negative leads together (black wires ). This should leave you with a positive and negative lead coming off the last circuit. Use hot glue to fix wires in place so that they do not block any of the surface mount LEDs.

Next, solder the positive lead coming off the LED circuits to the positive lead of the AA battery holder (the circuit works at 3V, if you want to squeeze a longer life cycle out of your circuit use two C or D cell batteries instead ! ). Don’t forget to add heat shrink tubing to one of the wires BEFORE soldering!

Then, solder a roughly two foot length of double wire (I snipped mine off a defunct 12V power supply but regular speaker wire could be used to the same effect ), to a panel mount SPST (Single Pole, SingleThrow ) or a SPDT (Single Pole, Double Throw ) toggle switch. Solder one of the two wires to an outside lug of the switch and the other to the middle lug of the switch. Now, solder the other end of one of the two wires to the negative lead coming off the AA battery pack and the other wire to the negative lead coming off the LED circuits. It doesn't really matter which wire gets soldered where in this case as you can orient the toggle switch to turn on in either direction.

This next step is optional, but I proceeded to de-solder the tilt switches from every circuit board as I wanted them all to retain the same orientation.

Use more hot glue to keep the wires tidy and out of the way of the surface mount LEDs and some more to affix the AA battery pack to the back of the foam core. Pop some AA batteries in to test that everything works as it should.

This completes the circuit for the LED insert !

Step 7: Installation of the LED Insert

Hot glue some strong magnets to the LED circuit side of the foam core base. These magnets will hold the LED insert to the underside of the steel grate, protecting it from the logs. Next, using an appropriately sized drill bit or stepped drill bit (illustrated ), enlarge one of the vent holes of the fireplace’s door assembly. Then, fish through the toggle switch and install its lock washer and nut to secure it in place. Proceed to re-install two fresh AA batteries (rechargeable if possible ) into the battery pack and affix the magnetized LED insert to the underside of the steel grate. Test again that everything works as it should.

Step 8: Adding the Logs

I purchased a bag of firewood at my local corner store, but you can split your own logs to use for this purpose. *A word of warning: make sure that the logs you intend to use are bone dry and free of critters, before bringing them into your living room !

As the logs are purely decorative (they simply help sell the realism of the insert ) any type of wood can be used. Heck, you could even use a pile of 2’ x 4’ off cuts, newspaper logs, tongue depressors, guitar necks, failed 3D prints, cut up hockey sticks, etc.!

First, turn on the LED insert and start to place the logs in an attractive fashion, which equally follows a certain degree of burn logic (leave air gaps between pieces, for instance ). Use the logs to surround the perimeter of the LED insert, leaving a space in the middle of the pile. This will allow the rhythmic, pulsating glow emanating from the LED insert to really shine. Overall, try to aim for a log placement that encourages the light to be bounced around whilst keeping the LED insert hidden.

For a more realistic look, use a blowtorch to scorch the logs to make them appear charred. To achieve absolute realism, pluck some half burnt logs from a campfire (once the fire has been extinguished of course! )

Step 9: Enjoy the Glow!

Close the fireplace doors, flick on the LED insert and bask in the warm glow of your renewed hearth! We’re thrilled with how the LED Fireplace Insert turned out and were delightfully surprised to discover that the batteries lasted for several days with the insert running continually, before having to be replaced. Theoretically, if you only turn on the insert for a few hours intermittently, the batteries could potentially last up to a month! And, if you decide to swap out the AAs for some C or D cell batteries, you could potentially stretch that month out to several months! The ON/OFF switch is conveniently placed and the insert can be turned on and off with a big toe. As a side note, the bulbs that I purchased have 3 modes, a traditional flickering flame, a constant amber glow, and a slow pulsating glow. Our preferred mode is the flickering flame. If you decide to make this quick and simple project, please share your version below!


Mr. Ham

*Achieving the realistic glow of a real fire is only half the battle of selling this LED Fireplace Insert. It is in dire need of some crackling fire sound effects! Have an idea on how best to achieve this? Post it in the comments below!

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