Why go hybrid?

[roastytoasty]

Hi, all. I'm selecting my first wood-burning fireplace insert, so I've been learning about different brands and types. There are several Lopi dealers near my home with showrooms, so I've had the chance to see their inserts in person, and I like the look of them. But they no longer make non-catalytic inserts, and I don't get the appeal of the hybrid thing. Even the dealers seem not to like them. They seems like the worst of both worlds. Or maybe I'm missing something.

People say you have to operate catalytic and non-catalytic inserts differently. Since Lopi NexGen Hybrids have both reburn tubes and a cat up top, do you operate them like they're catalytic or non-catalytic?

I've seen several diagrams of cat stoves like this:

https://cdn.shopify.com/s/files/1/0049/1388/9409/files/cross-section.jpg?v=1613154672

According to that diagram, the cat is typically protected from flames by a shield. As I understand it, once the stove reaches 500 degrees, you close the damper. Then the products of primary combustion flow around the shield and through the cat.

But I don't recall seeing a shield like that in Lopi hybrids. I recall seeing the cat right on the firebox ceiling. I've read that cats are fragile and can be damaged by flames and high heat. Wouldn't a Lopi cat be vulnerable to flames and high heat where it's positioned, unshielded at the top of the firebox?

If I want a few hours of beautiful fire for ambiance, I'd just leave the damper open, right? But that raises two concerns: 1) Wouldn't flames for hours damage the cat? And wouldn't the insert just operate like a less efficient non-cat insert, since it has fewer reburn tubes to make room for a cat?

Seems like burning hot enough to utilize the reburn tubes could damage the cat, but if I close the damper at 500 degrees to utilize the cat, the reburn tubes won't be used.

Those of you with Lopi hybrids, am I misunderstanding something here? What's the appeal? Why did Lopi abandon non-catalytic altogether? My fireplace is a bit odd, ruling out many other inserts due to clearances and dimensions, but Lopi makes a few models that could work, so I'd love to have my mind changed.

 

[begreen]

They changed them to pass EPA testing and potentially so that they qualified for the tax credit. Now that is going away.
FWIW, Osburns, Pacific Energy, Country, and some Regency inserts are still not hybrids.

 

[Todd]

You want to run the stove with the damper closed once up to temp. You will still see a nice fire from the secondary air tubes and it won’t hurt the cat.

Some of these hybrids have the cat exposed without a shield but are made from stainless steel so they can take it for the most part but also take more maintenance since they are exposed to more fly ash.

 

[roastytoasty]

They changed them to pass EPA testing and potentially so that they qualified for the tax credit. Now that is going away.

Yeah, that makes sense. I wonder if they'll reintroduce non-cats now that the tax credit is gone.

 

[roastytoasty]

FWIW, Osburns, Pacific Energy, Country, and some Regency inserts are still not hybrids.

Unfortunately, only a few of those work for us. We have an elevated, double-sided, see-through fireplace. With the exception of a few of the smallest models, all SBI inserts require 84" clearance to the ceiling. We only have 77.5" clearance.

We have a floating concrete hearth elevated 13.25" off the floor that only extends 7.75" inches in front of the firebox. We don't know how much weight it can support, so we really need a flush insert. All but Regency's smallest non-catalytic models would hang off the edge of our hearth. That's true of several other brands too. We were thinking about an IronStrike Striker C160, for example, but its blower compartment would hang off the edge of our hearth. We really don't want the noise of a blower, so we've thought about installing without one, which would shave a few inches off the front of many models. But, never having had an insert, we're not sure how necessary blowers are. Even if we initially install without a blower, we'd want the option of installing one later.

Pacific Energy's Neo 1.6 and 2.5 look promising, but there don't seem to be any dealers nearby with those in their showrooms.

 

[roastytoasty]

You want to run the stove with the damper closed once up to temp.

Is it really necessary to close the damper as soon as temp reaches 500?

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This video suggests burning a load of wood to establish a coal bed before closing the damper. If that can be done without damaging the cat, then it might still be possible to enjoy a few hours of beautiful flames before closing it down. But the exposed position of the cat has me worried. People are always saying they're so fragile.

 

[roastytoasty]

Some of these hybrids have the cat exposed without a shield but are made from stainless steel so they can take it for the most part but also take more maintenance since they are exposed to more fly ash.

But Lopi cats are ceramic, right?

 

[Todd]

Maybe I misunderstood, are we talking about closing the air control damper or the bypass? Once your up to temp you close the bypass and adjust the air damper down in stages. Best to use a thermometer and watch the flames as to when to do this.

 

[Todd]

But Lopi cats are ceramic, right?

Not sure

 

[stoveliker]

If the bypass is open, the impedance for gas flow will be much lower going thru the bypass hole than thru the cat. So I suspect that almost all flow (and thus flame) should go to the bypass hole and not the cat.

 

[begreen]

all SBI inserts require 84" clearance to the ceiling. We only have 77.5" clearance.

Where did this number come from? It applies to their freestanding stoves, but I don't recall seeing it in their insert docs. I just randomly checked the Osburn 2400i and did not find a ceiling clearance spec, just mantel and side walls.

PS: a flush insert is going to need the blower to convect heat into the room.

Can you post a picture of the fireplace? It sounds like with this raised hearth that simple ember protection hearth pad extension could work here for some inserts.

 

[roastytoasty]

If the bypass is open, the impedance for gas flow will be much lower going thru the bypass hole than thru the cat. So I suspect that almost all flow (and thus flame) should go to the bypass hole and not the cat.

Hmm, that makes sense. According to the diagram here, the cat is shielded on bottom (though not in front) by the baffle. Maybe that's enough protection, if gases are already inclined to flow away from it toward the back of the stove. Though I can't really tell from that diagram where they'd flow when the bypass is left open.

 

[roastytoasty]

Where did this number come from? It applies to their freestanding stoves, but I don't recall seeing it in their insert docs. I just randomly checked the Osburn 2400i and did not find a ceiling clearance spec, just mantel and side walls.

I don't see a 2400i here, but the 84" I mentioned is clearance measurement Q in the "Minimum Masonry Opening and Clearances to Combustibles" sections of the OB01705, OB02016, OB02028, OB02045, OB02700, and OB03510 installation manuals. Only the Matrix 1900, with its 1.03 cubic foot firebox, gets away with a mere 72".

This seems to be the case with all SBI inserts. The smallest models sometimes require only 72" from the bottom of the insert to the ceiling, but others all require 84", which rules out about a half dozen brands for my fireplace. 😭

 

[roastytoasty]

Can you post a picture of the fireplace? It sounds like with this raised hearth that simple ember protection hearth pad extension could work here for some inserts.

Yes, sure can.

 

[roastytoasty]

Can you post a picture of the fireplace? It sounds like with this raised hearth that simple ember protection hearth pad extension could work here for some inserts.

My floor is painted concrete, which I'm told is noncombustible according to local codes, so I don't think I even need ember protection (unless I just want to save the paint from char marks). But I don't know how much weight that cantilevered concrete hearth can support, so I wouldn't want an insert extending too far onto it. And it would look pretty goofy to have an insert hanging over the front edge of it, as many would (since it only extends 7.75" inches from the firebox).

 

[begreen]

If the hearth is done right to code then it is continuouse and reinforced with rebar. There shouldn't be any issues here. The Lopi hybrid inserts are good quality, I just didn't want choices to be narrowed due to misconceptions.

The PE Neo 2.5 looks like it would work.

Also take a look at the Osburn Inpire 2000 for a nice flush unit comparison.

https://www.osburn-mfg.com/en/products/wood-inserts/inspire-wood-insert/

 

[EbS-P]

If you like the pass through look you can choose not install the surround. That might influence choices. The liner can be concealed by piece of black 8” stove pipe.

 

[roastytoasty]

If the hearth is done right to code then it is continuouse and reinforced with rebar. There shouldn't be any issues here. The Lopi hybrid inserts are good quality, I just didn't want choices to be narrowed due to misconceptions.

The PE Neo 2.5 looks like it would work.

Also take a look at the Osburn Inpire 2000 for a nice flush unit comparison.

https://www.osburn-mfg.com/en/products/wood-inserts/inspire-wood-insert/

Yeah, a Neo might work, though I haven't found one in a showroom nearby, and I'm hesitant to buy anything without seeing it first.

Like most SBI inserts, the Osburn Inspire 2000 requires 84" clearance to the ceiling, which rules it out for my fireplace. With the exception of the smallest models, every SBI insert I've seen requires 84" clearance. So Osburn, Drolet, Century, Englander, etc. are all ruled out, unless I want a 1 cubic foot firebox.

 

[roastytoasty]

If you like the pass through look you can choose not install the surround. That might influence choices. The liner can be concealed by piece of black 8” stove pipe.

That's an interesting idea. I do like the see-through fireplace. I'll miss it, even though I'll likely burn an insert much more often.

Some models that otherwise would hang off the front edge of my hearth might fit if I left off the surround and was able to install a few inches further back. But not many insert models provide product photography of their sides or back, so it's hard to know what they'd look like without a surround. 🤔

 

[begreen]

Like most SBI inserts, the Osburn Inspire 2000 requires 84" clearance to the ceiling, which rules it out for my fireplace.

This sounds like a different situation. This is for the Inspire insert. Have you contacted SBI customer support with this concern, I don't think it applies here.