Time for cat #5!

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Highbeam

Minister of Fire
Dec 28, 2006
20,873
Mt. Rainier Foothills, WA
Since the beginning I have been tracking each cat’s lifespan and this latest one was one of the longest at 20 burning months, or about 12000 hours at low 95% of the time burning softwoods. I believe that burning on low is actually harder on a cat because the cat is doing all the work with no primary flame. The cat meter is always quite high though stove output stays low.

I am impressed with how easy it is to swap these cats. The new ones are cheap at 230$ and come with a new gasket. My old cats look perfect, no physical damage, but just stop working rather suddenly. This last one would stall at medium thermostat settings.

I also decided to trash my collection of used cats.

Yes, they’re cheap. I just sold a 5 cords of firewood 1/3 cord at a time for 200$ each. Just pop a new cat in to keep it running efficiently, minimum pollution, and maximum burn times. You’ll quickly save enough wood to pay for the new cat.

The Midwest Hearth cat warranty expires after 12000 hours of use which is coincidentally the average I’ve gotten per cat over the last decade.

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Can platinum be recovered from the spent cats?
How old is your stove now, 13 yrs?
 
I suspect that Highbeam has tried most things, but along with farmwithJunk I'd like to hear about the differences found between metal and ceramic cats.
 
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Have you tried a metal cat?
You can see in one photo that there is a dead steel cat in there. It was a BK brand cat and worked just fine but didn’t last very long at all. I do not recommend steel cats. They clog, they cost more, they don’t last as long, and offer no advantage unless you’re clumsy enough to drop cats since they don’t break like ceramic!

I did do a full vinegar boil on one cat and it helped get me a few more months of life so I keep that knowledge as an emergency tool. Remember though cats are cheap, and the time and materials for that cat boil was not financially positive. Waste of money. The BK design requires that you replace a gasket every time you remove the catalyst so I don’t remove the catalyst until it’s time for replacement.

Some people only replace tires after the steel belts are sticking out and scratching the fender. Don’t be that guy. The drop in efficiency from a used up cat costs you so much wood that you’re just throwing money away to prove some sort of point.

I immediately ordered my next cat to have on hand for the next replacement. It wasn’t that long ago that supply chain issues could have been a problem.
 
Can platinum be recovered from the spent cats?
How old is your stove now, 13 yrs?

It went into service in 2012 so we are now in burn season #12 and I completely wore out 4 cats in 11 “years” and each time I pushed way beyond their end of life because I’m cheap, thought it was just steam, or was hoping the huge change in behavior was just temporary.

For those who don’t know I have a 9 month heating season, full time burner, 95% on low, burning mostly softwoods. Last summer I installed a heat pump so going forward I may get more years of service per cat but I do not expect to get more hours of service.

Wood is very expensive, cats are cheap, high levels of visible smoke is damaging to the hobby, industry, chimney, and irritates neighbors. Just replace it when it’s time.

After selling wood this year I see just how much wood it takes to fund a new cat. I save that much wood with a nonspoiled catalyst very quickly.
 
You’re getting $200 for 1/3 of a cord? Wow! I’m seeing $50-75 for 1/3 cord around here. I paid $500 for 5 loggers cord of Oak logs. Buying a new cat every other year wouldn’t be worth it for me.
 
I immediately ordered my next cat to have on hand for the next replacement. It wasn’t that long ago that supply chain issues could have been a problem.
Agree with that. My stove is new, and if the combustor doesn't last 10 years ;) BK should be providing one under warranty. But that would require sending it in and waiting for the replacement. I just ordered one to have in stock.
 
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It went into service in 2012 so we are now in burn season #12 and I completely wore out 4 cats in 11 “years” and each time I pushed way beyond their end of life because I’m cheap, thought it was just steam, or was hoping the huge change in behavior was just temporary.

For those who don’t know I have a 9 month heating season, full time burner, 95% on low, burning mostly softwoods. Last summer I installed a heat pump so going forward I may get more years of service per cat but I do not expect to get more hours of service.

Wood is very expensive, cats are cheap, high levels of visible smoke is damaging to the hobby, industry, chimney, and irritates neighbors. Just replace it when it’s time.

After selling wood this year I see just how much wood it takes to fund a new cat. I save that much wood with a nonspoiled catalyst very quickly.
If the wood is paying for the cat then it's a no-brainer. Still, that's well over $1000 for 12 yrs of service. So far, we're at under $100 for 14 yrs. with no neighbor complaints about smoke. The heat pump should help a lot with reducing the 9 months of wood heating down to 5.
 
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You’re getting $200 for 1/3 of a cord? Wow! I’m seeing $50-75 for 1/3 cord around here. I paid $500 for 5 loggers cord of Oak logs. Buying a new cat every other year wouldn’t be worth it for me.
Yes! With a waiting list. This is of course the actual sub 12% MC doug fir that's been in a shed for two summers that many people think you can't buy but it still seems like a lot of money to me. People are happy to pay it and I'm happy to sell it for that much. I do like processing wood, not stacking too much.

What the heck is a "loggers cord"?
 
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Loggers cord is just a local thing here where they bring 8’ logs. They still measure a cord as 4x4x8 but expect to lose 15-20% after processing.
 
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If the wood is paying for the cat then it's a no-brainer. Still, that's well over $1000 for 12 yrs of service. So far, we're at under $100 for 14 yrs. with no neighbor complaints about smoke. The heat pump should help a lot with reducing the 9 months of wood heating down to 5.

One of the people that I sold wood to told me that his small home in Enumclaw costs 1000$ per month in oil to heat in the winter. Sure, it looked like the home was from 1920 but it was fancy. 1000$ ain't what it used to be.

With the cat stove, I can do things that I couldn't do with a noncat like burn very low and slow. Your point is valid though that if low and slow is all I need then I may choose to run the heat pump instead but it is more expensive and of course our electricity is 25% coal, 25% gas, and the rest hydro/wind/solar. Burning wood is greener as well as cheaper for me.

Even though my cost for wood fuel is very low, I suppose I should be using the price that I could sell it for in analysis of fuel costs. My wood heat suddenly became a very expensive way to heat!

I burned a couple of loads in the shop noncat stove yesterday. Zero visible emissions, lively fireview, clean glass, and no replacement cat. It was nice but I did blow through a lot of wood. Maybe I should get a heat pump for the shop! I would like to get a heat pump boiler if they ever become as available as the ductless heat pumps.
 
One of the people that I sold wood to told me that his small home in Enumclaw costs 1000$ per month in oil to heat in the winter. Sure, it looked like the home was from 1920 but it was fancy. 1000$ ain't what it used to be.

With the cat stove, I can do things that I couldn't do with a noncat like burn very low and slow. Your point is valid though that if low and slow is all I need then I may choose to run the heat pump instead but it is more expensive and of course our electricity is 25% coal, 25% gas, and the rest hydro/wind/solar. Burning wood is greener as well as cheaper for me.

Even though my cost for wood fuel is very low, I suppose I should be using the price that I could sell it for in analysis of fuel costs. My wood heat suddenly became a very expensive way to heat!

I burned a couple of loads in the shop noncat stove yesterday. Zero visible emissions, lively fireview, clean glass, and no replacement cat. It was nice but I did blow through a lot of wood. Maybe I should get a heat pump for the shop! I would like to get a heat pump boiler if they ever become as available as the ductless heat pumps.
12,000 hours…… how many cords is that? You paid for cats what some pay to lease a propane tank. I just don’t see the market for heatpump boilers taking off. To complex. Storage buffer tanks resistive back up heat. Mini split, one hole, connect wires and tubing (evacuate line set if needed) open valve and turn on. I see radiant heat in new construction as a luxury and in old construction it’s going to be an obstacle to green electrification. It’s relatively simple to swap in a heatpump for a gas furnace. And stupid simple for homes with ducted AC.
 
12,000 hours…… how many cords is that? You paid for cats what some pay to lease a propane tank. I just don’t see the market for heatpump boilers taking off. To complex. Storage buffer tanks resistive back up heat. Mini split, one hole, connect wires and tubing (evacuate line set if needed) open valve and turn on. I see radiant heat in new construction as a luxury and in old construction it’s going to be an obstacle to green electrification. It’s relatively simple to swap in a heatpump for a gas furnace. And stupid simple for homes with ducted AC.
Are there any general guidelines for the cost ratios for gas furnaces v. heatpumps, assuming existing ducted A/C?
 
Are there any general guidelines for the cost ratios for gas furnaces v. heatpumps, assuming existing ducted A/C?
Gas price and electricity price vary region to region but there should be a statement like
“If your electricity price /gas price is below/above this number….the. A heatpump saves you money” But I haven’t seen it. System costs vary a lot too. Maybe I’m just more aware now but it seems like there are a lot more hvac trucks/vans on the road today.
 
12,000 hours…… how many cords is that? You paid for cats what some pay to lease a propane tank. I just don’t see the market for heatpump boilers taking off. To complex. Storage buffer tanks resistive back up heat. Mini split, one hole, connect wires and tubing (evacuate line set if needed) open valve and turn on. I see radiant heat in new construction as a luxury and in old construction it’s going to be an obstacle to green electrification. It’s relatively simple to swap in a heatpump for a gas furnace. And stupid simple for homes with ducted AC.
About 8-10 cords over 12000 hours. That 1000$ quoted was for 11 seasons so less than 100$ per year. That gets paid for with like a few wheelbarrows of wood.

Heat pump boilers don’t need a buffer tank, don’t need backup resistance heat. Not sure why you would want to add those things. It’s just like a minisplit but to heat water and other countries already have them.
 
If the wood is paying for the cat then it's a no-brainer. Still, that's well over $1000 for 12 yrs of service. So far, we're at under $100 for 14 yrs. with no neighbor complaints about smoke. The heat pump should help a lot with reducing the 9 months of wood heating down to 5.
I'm not following your post; are you saying your cat is that old or you don't have a cat stove, therefore you are under $100 over 14 years?
 
I'm not following your post; are you saying your cat is that old or you don't have a cat stove, therefore you are under $100 over 14 years?
He has a noncat so hasn't bought cats for 14 years so didn't have to spend as much money on cats. Fun fact, I reduced my wood consumption by 20% when I moved from a modern noncat to this BK cat stove at my home. That's a lot of money. He said he spends 400$ per cord which is not unreasonable and probably uses 2 cords per year. So if he could save 20% on his fuel bill by moving to a cat stove as I did then he would save 160$ per year in fuel. Over 14 years, that's $2,240 dollars of savings and he would have spent about half that in cat costs.

Soooooo, running the inefficient noncat has cost him an extra $1000 even after buying all the cats. But then he would have to look at an ugly cat stove in his living room and that may be worth the extra operating cost.
 
He has a noncat so hasn't bought cats for 14 years so didn't have to spend as much money on cats. Fun fact, I reduced my wood consumption by 20% when I moved from a modern noncat to this BK cat stove at my home. That's a lot of money. He said he spends 400$ per cord which is not unreasonable and probably uses 2 cords per year. So if he could save 20% on his fuel bill by moving to a cat stove as I did then he would save 160$ per year in fuel. Over 14 years, that's $2,240 dollars of savings and he would have spent about half that in cat costs.

Soooooo, running the inefficient noncat has cost him an extra $1000 even after buying all the cats. But then he would have to look at an ugly cat stove in his living room and that may be worth the extra operating cost.
This is assuming his cat life interval would be the same as yours, correct?

BKVP
 
Not doubting you saved 20% switching from the Heritage to BK but depending on the stove and other variables that number could be much less. The difference in efficiency between most non cats and cats is usually less than 10%.
 
No need for guessing and there is still much more to this most recent study, just under limited release. Full study can be posted soon, once deemed "sharable".

Environment Canada just paid to have a VERY extensive study done on efficiencies, VOC's, black carbon etc. It is based upon an Italian cordwood test method. The finding are very interesting, especially given the regulators are really looking at VOC's. But this is a snip on the 93 tests they did as it relates to efficiency. (We can start a new thread once the entire study can be posted)
 

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Soooooo, running the inefficient noncat has cost him an extra $1000 even after buying all the cats. But then he would have to look at an ugly cat stove in his living room and that may be worth the extra operating cost.
That was just rounding. Midwest Hearth sells the cat for $239 + tax, so more like $260 each and probably higher in the future or at least $1300 for the next 5 cats?
 
That was just rounding. Midwest Hearth sells the cat for $239 + tax, so more like $260 each and probably higher in the future or at least $1300 for the next 5 cats?
With cat inflation also comes wood inflation. Can’t really guess whether either item will change. Cats have remained very steady.

The big “leap” is the 20% wood savings which is what I measured as have many other full time wood heaters but that’s variable. Wood usage efficiency over a winter is not equivalent to the steady state efficiency rating the epa gives a stove.

I understand that this is academic and just for fun.
 
This is assuming his cat life interval would be the same as yours, correct?

BKVP
Yes, to be conservative for Bg. Savings are even greater if he gets more “years” of cat life due to his much lower usage. Good point.
 
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