I started with some hot coals at 4:40 pm est it started putting out heat at 5pm it is 6:24 pm and still burning good. I only put 3 in my quadrafire 2700i. The bricks were $3.99 for 8 bricks or $210 for a skid of them. I bought 2 packs or $8 worth to try and have some fun with. I will report back and let you guys know when they stop putting out heat