For those who wonder

How many square feet is your house?

I went with the Kuuma vapor fire which is a wood burning gasification furnace and distribute the heat throughout the 3400 square feet with the ductwork.

A wood stove just wouldn't have been able to achieve the same even level of comfort in every room as the Kuuma does.

 

If the stove is properly sized, installed, and operated, low and slow is a great way to keep your house warm. Occasionally you might need to bump it up to medium output but low output is still a lot of heat.

 

I probably burn my stove low and slow 90% of the time. Low and slow is probably the most efficient air setting for most stoves. If the stove is too small for your home you’ll most likely be burning too hot and wasting heat up the flue.

 

And then you’ll have coal build up issues. If you need to run the stove hot to stay warm during normal winter weather then you won’t be able to stay warm when it gets really cold. The wide range of outputs available from a cat stove is very useful.

 

I think I need more chimney…. And a new catalyst, but they are on back order.

 

Check aftermarket?

 

oh man, I don’t know what stove you’re burning but I’ve seen supply chain issues affect catalyst availability. I’ve also been through enough cats to know that in my application (low and slow with low btu fuel) they fail fast and hard. I keep a brand new cat on the shelf and recommend all of us do the same. Without a good cat our cat stoves kind of suck.

 

Absolute steel…. My fault for procrastinating… they were in stock when I checked in July…. Lol

 

I have a spare cat sitting in the closet for when the one in the fireview fails. I am on year 3 with the steel cat that came with the stove. I bought it last summer, seems like they are always in stock off season.

 

Bump.

Still wondering what the square footage that you're heating..........

 

You know better Yoop; it’s cubic feet that you heat.. ask about my 16 foot ceilings!!

 

I kinda wish Blaze King still made their Apex(?) whole house cat wood furnace...as much as I like my Kuuma, I still think that would be interesting to try out...last I heard BKVP said they had no plans to make them again...I actually think a cat/hybrid whole house wood furnace would possibly be the ultimate in forced air wood heating systems...a gasifying wood boiler with hot water storage and radiant emitters is the cadillac wood heat system, in function, and in price too, unfortunately.

 

Kind of a tough thing to make an EPA approved forced air furnace. Very few left after 2020 emissions reduction requirements. Several mfgs just closed their doors, the demand is getting pretty small to pump tons of $$$ into R&D, testing, certification and product launch.

BKVP

 

Don’t go thinkin’ that disruption and attempted destruction of the industry was an innocent byproduct of those regs, either.

And that’s all I’ll say here, lest I veer into politics.

 

Might as well, “Spitter’ up, Walter!”, no sense backing away from the truth.

 

I like this idea of CAT stoves running low and slow, and the discussion of correct stove size is of absolute importance.

My black rock burner runs very similar to these CAT stoves except in an opposite way, which I’ll explain here in a moment.

I’m of the opinion that there’s more to it than just the stove top temperature and that other pertinent information is being left out for potential stove buyers that is absolutely critical when considering and comparing these stoves as home heating prospects.

Lots of people talk square feet of the home and discuss the insulation value of their home. Fewer people mention cubic feet which is actually a better consideration when sizing a stove.

These same people talking about the insulating value often fail to consider something equally important as home insulation value; stove mass weight which includes material thickness.

A good comparison to cubic feet of home space is square area in inches of stove material and even cubic inches of the stove.

These things absolutely do matter and absolutely do have an affect on proper stove choice and should be part of the stove selection process.

Combine all of these together then give stove top temperatures BUT also include temperatures taken from other spots on the stove. It’s good to know how hot the front runs, the sides, the rear, and the stove pipe…if nothing more than to get an overall better picture of how much heat the stove’s actually throw.

My black rock burner runs low and slow all season (except this season…abnormally high OAT’s and stove maintenance has prevented me lighting it as of yet).

Where you guys get lots of heat off the top of your CAT stoves, my stove top runs cool (165F all season regardless of other stove temps) all the time because of a heat exchanger in the top of the stove. The rear of my stove also runs very cool (around 180-210) because of a convection heat shield on the stove back that exits front of stove between stove top and top of doors. The sides often run around low 200’s. Obviously top sides are cooler and the closer to the bottom of sides towards the fuel load the sides get warmer, around 230ish.

The baffle in the fire box causes a rolling action of the flames (or heat since often there is no flames) and gases projecting the heat forward and down towards the front of the stove causing the front of the stove to give off the most heat, most often cruising around 275F, occasionally to 300F-350F and more rarely (one time in 4 years) 400F when it was -36F outside.

The single wall stove pipe I can place my hand on the pipe, and leave it there, anywhere along its length from low temps up to about 350ish on the stove front. Hotter than that I have to move my hand up to near the clay thimble where skin temps are never higher than 98F and even to a front stove temp of 420F I can still leave my hand on the stove pipe at thimble and leave it there as long as I wish.

This giant Hitzer 354 cruises along like that low and slow.

Try burning wood in it and all bets are off. All the above specs change because burning wood is a different animal. It simply burns differently.

However, some of the same thoughts apply to choosing a wood stove.

The Blaze Kings run closer to my coal stove than any other stove because of the thermostat regulator.

CAT stoves in general have hot stove tops. Unless the stove has rear and/or side shields for close clearance to combustibles (keeping rear and sides cooler) the stove body will emit somewhat even and lower temperatures than the tops will. Stove material thickness and mass weight all contribute and translate heat being dispersed.

Thicker materials, once charged with heat, tend to run like a heavy locomotive, they’re hard to pressed to slow down quickly and decrease heat lag time at stove tending time…which is over looked often. Keeping stove temps up means keeping home temps up which all translates to less wood usage trying to bring things back to temperature.

I am convinced that every stove should be of heavy mass weight for a given size, be they made of steel or stone. I’m talking about size to weight ratio for given firebox size should lean towards the heavier mass weight side of the ratio.

I’m convinced that CAT stoves work, particularly BK and WS stoves.

I’m convinced that the bi-metal regulator separates the men from the boys. WS needs to add one to their already stellar stoves, as do all other stove manufacturers.

I’m convinced that I’ll own both a WS and a BK in the near future.

 

Yeah thermostat controlled stoves are nice but you can have plenty of control without as long as your stove is setup to specs. A lot of the problem is all stoves are tested with a 15’ chimney with ideal draft so manufacturers tweak their stoves for optimum performance with that in mind.

Installing a pipe damper or tweaking the combustion air helps keep a stove in check with taller chimneys but then your messing with warranty or insurance issues.

The new 2020 regs were too strict imo. Too many manufacturers had to slap a cat in to clean up GPH and I feel many hybrids will have issues in the future and people with just forgo the cat when it comes time to replace.

I think a lot of stoves out there could benefit from secondary air control to keep stoves in check on taller chimneys. There are a few out there like PE, VC and I think the new Jotul F500 as well.

I’d like to rig up some kind of manual secondary control on my stove. I currently blocked about 25% of the unrestricted secondary air with a magnet and it works really well keeping the flue temps down on those colder high drafting days but there are times I’ve needed to block more or less.

 

One additional factor, to include with your excellent suggestions, that is the residents themselves.

I'll keep my larger, older home at 73F. My son and his family prefer 67F. Given individual preferences, specific gravity of various fuels, desired interaction with a chosen heater etc...getting the correct heater for a very specific need can vastly increase consumer satisfaction and heater performance.

BKVP