How long does a wood boiler last?

[Nofossil]

I'm trying to do an annual cost comparison for my wood / solar system, and I want to use a reasonable estimate of the lifespan of my wood boiler. It's an EKO 25, made of 1/4" steel plate. I have inlet water temperature protection to avoid condensation and corrosion.

Any real-world experience on how long such a beast should last before it's due for recycling?

Maybe I should do this as a poll....

 

[Hbbyloggr]

Relating to 1/4 plate, I made baffled type wood stoves back in 1974. I still have one of them in our living room, and until a few years ago was our only source of heat for the old Cape. It kept us warm even when it was 15-20 below. It was running just as hard as it could with the sides cherry red ( I did throttle it back a tad for fear of a melt-down ).
No firebrick on the bottom or sides, either. Five years ago I did notice a crack in one of the side plates, so I rolled it down to the shop and welded up the crack. It's been fine since then.
We still use it to help during the real cold times and to dry gloves, boots, jackets and such.

My point is, that 1/4 inch plate stove is still going strong after 33 yrs. At the time I was making them I offered a 20 yr warranty and to date have never had a return or complaint.

I had an Essex wood furnace that I took out of a home for a fellow ,with intentions of using it myself. After 20 yrs of service still looked in fine shape. The gassification refractory needed replacing but the 1/4 in boiler plate looked great.

Hbbyloggr

 

[webbie]

Depends a lot on design, steel quality and weld quality. Some defectively built models of waterstoves (years ago) developed leaks in 5 years. Gasifiers like Tarm and EKO will last much longer when they are used relatively heavily (storage, etc.)

With everything done properly, I think you can count on a 20 year plus life....with parts (refractory) replacement, of course. Also, things like small leaks in fittings can end up shortening the boiler life.....the rust and moisture often run down onto the boiler or wet the insulation.

 

[Nofossil]

Relating to 1/4 plate, I made baffled type wood stoves back in 1974. I still have one of them in our living room, and until a few years ago was our only source of heat for the old Cape. It kept us warm even when it was 15-20 below. It was running just as hard as it could with the sides cherry red ( I did throttle it back a tad for fear of a melt-down ).
No firebrick on the bottom or sides, either. Five years ago I did notice a crack in one of the side plates, so I rolled it down to the shop and welded up the crack. It's been fine since then.
We still use it to help during the real cold times and to dry gloves, boots, jackets and such.

My point is, that 1/4 inch plate stove is still going strong after 33 yrs. At the time I was making them I offered a 20 yr warranty and to date have never had a return or complaint.

I had an Essex wood furnace that I took out of a home for a fellow ,with intentions of using it myself. After 20 yrs of service still looked in fine shape. The gassification refractory needed replacing but the 1/4 in boiler plate looked great.

Hbbyloggr

Thanks. Unfortunately, I doubt I'll do as well, since mine is a boiler. I have water on the back side of that steel, eating away at it every day. Eventually, you start getting pinhole leaks and you're done. The only boiler data point that I have is my brother, who got 12 years out of a used boiler of unknown age.

 

[webbie]

Essex ARE boilers...and boilers typically outlast furnaces, because of that water! It keeps the temp of the wall at a point where they cannot warp, etc. - Water that is in a boiler system becomes "black", which means it loses the air in it - and then cannot easily rust. So keep in mind that corrosion is usually from the outside in....like the fitting leaks I mentioned.

 

[Eric Johnson]

I bought a used Royall 6150 boiler a few years ago on Ebay. I think it dated from around 1979. Solid unit. I fired it hard for 3 heating seasons and finally got rid of it because it smoked too much. But it never leaked. Royall is an ASME-rated wood-fired boiler, which puts in the same league as a Tarm. Every time I'd toss a big chunk in there too hard and "ring the bell" on the back plate I'd cringe. I bet the guy I sold it to gets another 20 years out of it.

I know you're dying to build your own, nofossil, but I wouldn't count on the EKO failing any time soon. Heck, they come with a 5-year warranty. What's yours--3 years old? I suspect it's built about as well as a Tarm, and they are warrantied for 20 years.

I love the black stuff in the pipes, Craig. Smells like fish oil. The sign of a healthy hydronic heating system.

 

[Hbbyloggr]

Nofossil,

I'll check back with you in 17 yrs to see how that old EKO is holding up. That's just about the time of the last installment payment , right?

Good luck and enjoy your investment !

Hbbyloggr

 

[Nofossil]

OK, I'll go with the 20 year number, and assume that my stainless storage tank and controller will last 20 years as well.

I've reduced my oil consumption by 700 gallons per year (from 740 to 40). At $3 per gallon, that's $42,000 over 20 years. Of course, oil might go up ;-)

I have at most $7000 invested, and I'll probably spend an average of $500 per year on wood harvesting related expenses (tractor amortization, woodsplitter, chainsaws, junk that I just HAVE to have).

This is my third season. That means I'll be just about break-even this coming spring, and I should be about $1600 ahead of the game every year afterwards.

Depending on how you do the math, that's an annualized return of 12% on the initial investment AFTER buying myself $500 of toys per year. Gives me a warm feeling above and beyond the heat from the boiler.

Perhaps more important to me, our 'fixed' expenses for heat have been reduced from $2100 per year to about $120 per year. If things get bad, we'll be warm.

Thanks for the encouraging words about boiler life. I feel like this experiment has turned out well.

 

[Hbbyloggr]

AND now for the sweetest part. Take that $1600 and invest it in Exxon or one of the forward thinking oil companies and get rewarded for not using their product.