Ok, yesterday I did an interesting test with my PH stove (CAT stove). We often get baked out of the room with not much going on in the firebox, so I assumed the cat was throwing off lots of heat. Well, confirmed!! WOW! So have many of you had both a CAT and a NON-CAT in the same room/setup in the past that you can compare the difference in heat output? I loaded my stove with a VERY small amount of wood, really just some kindling and one small split over a hot coal bed. I left the bypass open so the cat would not work, and shut the air down to normal and let it burn for a few hours. I did not get much heat out of it, the stove got hot, emmitted some heat but not much. Then, I did the exact same thing, same amount of wood, same starting temp, same temp outside... and this time engaged the CAT. WOW!! I can not beleive the difference in the amount of heat it output with the car running! It was baking!! Now I know where all that heat comes from when I don't see much going on in the firebox, WOW! So the question is, do the non-cat stoves jsut not put out 1/2 as much heat as the cat stoves? Is it that big of a difference in Cat vs non-cat stoves? Sure seemed like it to me!
You might also consider that for your burn without the cat, you had to leave the damper open. Perhaps a good amount of heat (and unburned gasses) went right out the open damper and up the chimney. But yeah, running a cat also extracts a lot more potential BTU's and warms the stove & room instead of just letting them go up the flue. Tube EPA stoves do the same but in a different way.
I agree with Gark. If you want to try to compare since you have a hybrid remove the cat and close the bypass. But remember that your stove wasn't designed to operate this way. But maybe it will give you a close example.
Cats have higher efficiency when they are new. The issue is that as they get older the efficiency drops.
It drops, but not significantly. A cat stove is still more efficient burning at lower temps than a non-cat stove. The purpose of a cat stove is flexibility and the ability to burn at lower temps. A non-cat stove is more efficient at high temps. A BK King will always be more efficient than the 30 when it is operating as it is intended, which is a controlled, even, heat output. Where as the 30 will jump up to 650-750 for 2-3 hours and then taper off over the following 6-10 hours. One is not better than the other. They just meet different needs.
I have had a Pre-EPA cast iron stove (Vigilant), a cast iron cat stove (Defiant), and a non-cat steel stove (30NC) connected to one chimney (not at the same time, obviously). All three stove are roughly the same size. The 30 is technically the biggest, but, it appears the fire box size includes the unusable space around the burn tubes. The Vigilant and Defiant have no burn tubes, so those fireboxes can be packed differently. When all three stove were running at high temps (650-750), there is little difference between the heat output. The Defiant and 30NC seemed more capable at moving warm air to different parts of the house. But the heat itself, within the room, offered little difference. The main difference was the burn time as the Defiant and 30NC easily offered longer periods of usable heat than the Defiant.
