Choosing a Pellet Stove: Cast Iron vs Steel

[MCPO]

With a pellet stove (unlike a wood stove), very little cast iron actually heats up, it's mostly in the heat exchanger and the surfaces around the heat exchanger. So it's pretty much all about looks. That's why we have it, and the heat helps a little too. What do you need an exhaust sensor for other than to get covered in ash and not work properly. That's why the settings are there on the outside of the stove. You can always hook up your stove to a thermostat, be it programmable, or the cheap slider. Plug and play!

That's a very good point if you are just thinking about radiant heat. However, my stove has cast iron heat exchangers which do provide more steady heat exchange than steel.

Mark

I`m not convinced cast is better than sheet steel. From what I can gather they are very close even when used as randiant heaters as in (wood stoves).
Cast iron does hold heat longer but takes longer to heat up. I believe heat exchangers in most heating systems are sheet steel vs cast iron for reason of more efficient / quicker heat transfer. However if you can find info contrary to above, I`d be interested in reading it.

 

[Utilitrack]

We purchased a Lopi Leyden and had it installed by Rocky's, they were great to deal with. Lopi has that classic cast woodstove look as well. Don't believe what you read about them in Consumer Reports, the problem that they had was with an engineer's wet dream, they installed this fuel gate in the chute to avoid potential burn backs and caused more problems that they could possibly solve. Gates have been removed, Lopi's are running smoothly again. Though it would be way overkill for 500 sf.

 

[Tom Pencil]

Parents have a Harman PC-45(steel). I have Harman Accentra Insert(Cast). We normally burn the same pellets but I feel may parents stove is warmer. Maybe due to the fact that theirs is free standing and they get radiant heat from the sides. Personally for looks I like the cast look.

 

[Dr_Drum]

Cast Iron has better thermal conductivity than mild steel (all things being equal). Cast Iron also has a lower thermal expansion, is less dense, and is of course "castable". It's a better choice for heat transfer in water or air. However, steel is stronger and items can be made lighter with less material and it still has a good thermal conductivity. Whether or not a material holds heat longer is a product of thermal conductivity, mass and density, but Cast Iron should shed heat faster and cool off quicker than the same amount of steel, although this is contrary to popular belief, i.e. cast iron frying pans and bath tubs. In these cases there is always a substantial mass difference. Just google, there's tons of supporting data on characteristics of materials.
Mike -

 

[mark d fellows]

Cast Iron has better thermal conductivity than mild steel (all things being equal). Cast Iron also has a lower thermal expansion, is less dense, and is of course "castable". It's a better choice for heat transfer in water or air. However, steel is stronger and items can be made lighter with less material and it still has a good thermal conductivity. Whether or not a material holds heat longer is a product of thermal conductivity, mass and density, but Cast Iron should shed heat faster and cool off quicker than the same amount of steel, although this is contrary to popular belief, i.e. cast iron frying pans and bath tubs. In these cases there is always a substantial mass difference. Just google, there's tons of supporting data on characteristics of materials.
Mike -

Thanks for the info.

 

[MCPO]

Cast Iron has better thermal conductivity than mild steel (all things being equal). Cast Iron also has a lower thermal expansion, is less dense, and is of course "castable". It's a better choice for heat transfer in water or air. However, steel is stronger and items can be made lighter with less material and it still has a good thermal conductivity. Whether or not a material holds heat longer is a product of thermal conductivity, mass and density, but Cast Iron should shed heat faster and cool off quicker than the same amount of steel, although this is contrary to popular belief, i.e. cast iron frying pans and bath tubs. In these cases there is always a substantial mass difference. Just google, there's tons of supporting data on characteristics of materials.
Mike -

Actually some (or all ?) Quadrafire pellet stoves uses an aluminum heat exchanger . I believe the new 94% efficient wall hung gas furnaces use copper and I know some point of use water heaters use aluminum too.
Here`s an interesting related article on cast vs steel .
(broken link removed to http://www.mainewoodfurnaces.com/SteelvsCastIron.shtml)

 

[Dr_Drum]

. . . Actually some (or all ?) . . . Quadrafire pellet stoves uses an aluminum heat exchanger.

I believe the new 94% efficient wall hung gas furnaces use copper and I know some point of use water heaters use aluminum too.

Here`s an interesting related article on cast vs steel .
(broken link removed to http://www.mainewoodfurnaces.com/SteelvsCastIron.shtml)

Some or all? I was only commenting on materials, not stoves. My book shows Cast Iron as always having a better heat transfer than any steel, stainless is worse. Aluminum is best, an awesome choice for heat transfer, and is used in most industrial shell & tube heat exchangers I have worked with, but it has a low melting point of 1250 F or so, the highest thermal expansion, and is weak (comparitively). I have only seen aluminum used in a "water jacketed" situation. Quad must have engineered for the difference in thermal expansion (over double) between Aluminum and Steel. Just don't bolt one to the other. Good link, but I have never personally seen anything but steel in industrial high pressure steam boilers, and most residential as well so I'm not sure why their crying about Cast having preference? I have a steel boiler. I think most manufacturers offer both, Cast is just more expensive.
Mike -

One thing to keep in mind is that if it takes twice the thickness of an Aluminum heat exchanger tube to match the strength of a steel or cast one, the benefits of having aluminum are diminished. Gotta compare apples to apples.

;-P

 

[bobforsaken]

Well I did it I'm getting the XXV installed on Oct 22nd. I eventually decided to go with Harman with the best dealer I've dealt with... It was between the XXV and P43. It ended up being $700 more for the XXV but I didn't want to look back years from now and regret not getting the stove that I liked the best to save 700 Bucks.

Thank you, everyone, for your input!