Kuma Cascade LE - Heat output / Liner questions

[skooma]

Hi,

I had a Kuma Cascade LE insert installed into a masonry fireplace recently and have been a little concerned by the heat output of it and the install. For reference, the room I'm trying to heat is only 650sqft but has a 16ft tall ceiling with an open loft area above. There is a bedroom attached through a corridor and a stairwell leading to the ground floor of the home which is unfinished. With this stove being rated for 2800sqft, I assumed it would be cooking us out of the house. The house has a lot of older windows and with the floor below the stove being unfinished, there's probably a lot of heat loss, but I figured this large stove could keep up.

I have a 9x13" terracotta chimney that's about 25' tall but they were only able to fit a 5.5" liner for some reason. And they ended up not insulating the liner because they said it was too tight. The Kuma manual says you must have at least a 6" insulated liner, so I'm not too happy about that. But I don't have any puffbacks of smoke as long as I open the damper and bypass, so I'm not sure if that's a serious issue I should bring up to the seller or not. I saw mention of the solid insulated oval liners in another thread, and I'm wondering why they didn't use that instead.

It's been getting down to 30*F overnight here and 50*F during the day, and I've been running this stove between 400*F and 650*F all day long, with wood around 18% moisture. I've been getting around 6-8 hours of burn time with a full load burning mostly oak and ash and the indoor temp in the room with the stove struggles to get up to 70*F, and on overnight burns it drops to 63*F, and there will be a nice bed of coals with the stove around 300-350*F, so I can just throw some wood in and it starts back up.

My questions is whether this is expected from an insert like this? I grew up with a Hearthstone freestander that would radiate so much heat that you can't stand near it, but with this insert and the fan on max speed (which is very loud, so I usually keep it around medium) I don't feel like I'm getting much heat out of it. I do plan on installing a ceiling fan in my loft area to help bring some of the warm air back down so maybe that will help. I also currently don't have a surround installed, and have the stove pulled out as much as possible, since I wanted to get more radiant heat out of it. But the top and sides of the stove stay below 250*F all the time so that's probably not doing as much as I had hoped.

 

[begreen]

The issue sounds like it could be more of a heat loss situation than a stove issue. The cubic footage being heated is more important than the sq fig. What are the walls? Are they well-insulated, stud construction or uninsulated cement?

A common source of low heat complaints in stoves is the wood. In order to get maximum output, the wood must be fully seasoned, ideally in the 15-18% mc range. Has it been properly tested for moisture content?

The liner installers took an easy out. This may have been because of trying to keep their bid competitive. Were they told the liner must be insulated? This is more of a code requirement, but also a safety issue. A too cool flue is going to build up creosote from the condensation of flue gases.

 

[skooma]

The issue sounds like it could be more of a heat loss situation than a stove issue. The cubic footage being heated is more important than the sq fig. What are the walls? Are they well-insulated, stud construction or uninsulated cement?

A common source of low heat complaints in stoves is the wood. In order to get maximum output, the wood must be fully seasoned, ideally in the 15-18% mc range. Has it been properly tested for moisture content?

The liner installers took an easy out. This may have been because of trying to keep their bid competitive. Were they told the liner must be insulated? This is more of a code requirement, but also a safety issue. A too cool flue is going to build up creosote from the condensation of flue gases.

It could very well be heat loss through the doorway to my bedroom and basement, which are poorly insulated. I plan on correcting that over time. With the door shut, it heats up pretty well, but still isn't exactly cooking me out of the room like I was expecting.
Regarding the installation, I originally paid for them to install and insulated liner but the installer said it was too tight. It seemed pretty easy for them to get the uninsulated liner in though, took about 5 minutes. Maybe they're just BS'ing me. I checked my local codes and don't see anything about it needing to be insulated, and the shop I bought it from says in their quote it is an "approved install". But if it's going to cause me issues down the line or reduce the performance, I think I would rather them install the 6" insulated liner per the manufacturers specs.

 

[moresnow]

Guessing your install did not include a block off plate? Worth researching if you didn't get one.

 

[skooma]

Guessing your install did not include a block off plate? Worth researching if you didn't get one.

No they just stuffed fiberglass insulation up behind the lintle.

 

[Highbeam]

So what’s the total square footage of the home.?

 

[skooma]

So what’s the total square footage of the home.?

1800sqft. It's two floors, 2nd floor is a finished living space, ground floor is a garage/shop that is unfinished with cinderblock walls. Home is around 30 years old, so not super efficient. For reference I used 450gal of fuel oil last winter to heat my home, so about $1600, which isn't terrible. My goal was to rely on just the insert to heat my home.
Regarding fans on inserts, are most people leaving them on high all the time to get max heat out of the unit? I been keeping mine around 50% all day because it's loud enough to hear across the house in my bedroom with it on high.

 

[Highbeam]

1800sqft. It's two floors, 2nd floor is a finished living space, ground floor is a garage/shop that is unfinished with cinderblock walls. Home is around 30 years old, so not super efficient. For reference I used 450gal of fuel oil last winter to heat my home, so about $1600, which isn't terrible. My goal was to rely on just the insert to heat my home.
Regarding fans on inserts, are most people leaving them on high all the time to get max heat out of the unit? I been keeping mine around 50% all day because it's loud enough to hear across the house in my bedroom with it on high.

Okay so 1800 SF and at least part of that (half) is double tall ceilings so you can increase that SF to 2700 or so, really close to the 2800 SF stove rating which is of course optimistic for such a small firebox. That thing is only 2.5 cubic feet and is an insert.

30 year old home is from late 90s so should be reasonably well insulated and sealed. 2x6 walls with actual insulation and double pane windows.

Heating capacity for that stove is 2200-2800. I would definitely keep the fans running but medium should be adequate.

Cascade LE-1 Fireplace Insert, Wood Stove Insert by Kuma Stoves

The Cascade LE-1 insert is perfect for medium sized fireplaces while allowing up to 11 hours of burn time. Get yours now at Kuma Stoves.

www.kumastoves.com

 

[gthomas785]

I think the 16' ceiling is your problem. If you climbed up to the ceiling I bet it'd be toasty warm up there.
Do you have a ceiling fan?
Edit: sorry missed the part about installing a fan. I think that is a good idea.

 

[begreen]

It could very well be heat loss through the doorway to my bedroom and basement, which are poorly insulated. I plan on correcting that over time. With the door shut, it heats up pretty well, but still isn't exactly cooking me out of the room like I was expecting.
Regarding the installation, I originally paid for them to install and insulated liner but the installer said it was too tight. It seemed pretty easy for them to get the uninsulated liner in though, took about 5 minutes. Maybe they're just BS'ing me. I checked my local codes and don't see anything about it needing to be insulated, and the shop I bought it from says in their quote it is an "approved install". But if it's going to cause me issues down the line or reduce the performance, I think I would rather them install the 6" insulated liner per the manufacturers specs.

Code requires an insulated liner when the chimney structure is less than 2" away from combustibles (interior) or 1" away if exterior. The stove manual's requirements are also key. What is the ID of the clay liner in the chimney, 7"x11"?

Uninsulated basement walls really suck out the heat, up to a third of what the stove is outputting. If this is not a basement and the walls are not underground but exposed, then the heat loss will be even greater.

Did they seal off the damper area? If not, installing an insulated block-off plate and, if there is room, a layer of insulation (like kaowool) behind the insert, can notably improve heat output.

 

[Highbeam]

Code requires an insulated liner when the chimney structure is less than 2" away from combustibles (interior) or 1" away if exterior. The stove manual's requirements are also key. What is the ID of the clay liner in the chimney?

Uninsulated basement walls really suck out the heat, up to a third of what the stove is outputting. Did they seal off the damper area? If not, installing an insulated block-off plate and, if there is room, a layer of insulation (like kaowool) behind the insert, can notably improve heat output.

I get the feeling that this is a three level home. Basement/garage, main floor, and loft. With the stove on the main floor so heat loss to the garage walls would be small. Loft probably pretty cozy. Masonry chimney on exterior wall is a heat suck.

Ceilings might be vaulted too so a hot pocket at the peak and less insulation due to the thickness of the rafters.

Winter hasn't even hit!

 

[begreen]

Could be, some pictures would save a lot of guessing.