Sq. Footage Ratings.... but What About Vaulted Ceilings?

[gtilflm]

We're on the cusp of getting a wood stove. The only remaining question is about "coverage". All stoves say something like "Will heat up to ______ sq. ft." However, that assumes a normal 8' ceiling height. Our issue is that we have REALLY tall ceilings in a great room where the stove would be going. So it seems like sq. footage isn't really the way to approach sizing the stove due to the volume of space. The great room ceiling at the low end is 13' and goes up to a peak of about 20'.

Here's a view of the space we're wanting to heat... (disregard the note showing the wood burning fire place against the west wall... plans changed)



It's hard to show this 2-dimensionally, but the blue boxed stuff has regular 8' ceilings with a loft above it that looks down over the great room. Lastly, we do have a big ceiling fan right about where the words "GREAT ROOM" are on the drawing. Let me know if more clarification is needed.

My main question is this: How should we approach sizing a stove in this situation?

Thanks.

 

[begreen]

Some companies used to list cubic ftg. heated instead. I haven't seen that for a while.

Ceiling fans will be required to help mix the hot air that is going to want to pool up near the peak of the high ceiling. With two, you could have one blowing upward and one blowing downward to create a convective loop. Or just run both in reverse in the winter.

The stove sizing is going to depend on the heat loss of the house. This will be affected by the insulation values, sealing, and the number/size of windows which are notorious heat losers.

Have the heat loss calcs been done already for the primary heating system? That can be a helpful guide.

Will there really be a wood stove next to the fireplace? Have you considered a modern EPA ZC fireplace that can do both 24/7 heating and provide a great fire view?

 

[gtilflm]

Some companies used to list cubic ftg. heated instead. I haven't seen that for a while.

Ceiling fans will be required to help mix the hot air that is going to want to pool up near the peak of the high ceiling. With two, you could have one blowing upward and one blowing downward to create a convective loop. Or just run both in reverse in the winter.

The stove sizing is going to depend on the heat loss of the house. This will be affected by the insulation values, sealing, and the number/size of windows which are notorious heat losers.

Have the heat loss calcs been done already for the primary heating system? That can be a helpful guide.

Will there really be a wood stove next to the fireplace? Have you considered a modern EPA ZC fireplace that can do both 24/7 heating and provide a great fire view?

This was new construction that was completed in 2020, and we were the general, so I know all the bits..... 😀

Heat Calcs: I do have this, but after it was done, some things changed. I do have a spread sheet that automatically calculates some things. What type of thing would you be looking for from that? It can give "Envelope Heat Load", "Building Design Heat Load", "Building and Duct Heat Load", "Maximum Heat Equipment Output" and other stuff.

Insulation, House Tightness, etc.: We're really dialed in on that front. Have R-60 in the ceiling and our blower door test (if you know what I'm talking about) was really good. Not quite to the level of a "net zero" house, but really tight.

Fireplace: There isn't a fire place there at all. That was something that we had to scrap mid-build due to budget. So now the corner wood stove is the route we're going.

 

[begreen]

Are the walls 2x6 or 2x4?

The building design heat load should be fine. How many sq ft will be heated?

Fireplace: There isn't a fire place there at all. That was something that we had to scrap mid-build due to budget. So now the corner wood stove is the route we're going.

Got it. Will the stove be heating 24/7 or more just nights and weekends? What will be the main fuel? Ponderosa pine, tamarack, doug fir?

 

[gtilflm]

Are the walls 2x6 or 2x4?

The building design heat load should be fine. How many sq ft will be heated?

Got it. Will the stove be heating 24/7 or more just nights and weekends? What will be the main fuel? Ponderosa pine, tamarack, doug fir?

Walls: 2x6

Sq. Ft.: At a min. the great room and kitchen, so 990. But then there's the loft above most of the rest of what you see on the diagram. That would technically add 730 more, but that's up high, so I would assume that that part will happen naturally due to the rising of heat (despite the ceiling fan's best effort). There's also approx. 730 more if you're counting under the loft (where it says Bedroom, Master Bedroom, and Den). So, I guess I don't have a solid answer on that. If you're asking what I want to be heated, I'd say the whole thing, but what needs to be heated is the 990 from the great room and kitchen.

Frequency: Not planning on 24/7. Most likely it will be hit and miss during the day/evening. We have gas forced air, so this would typically be supplementing that, adding ambience, warmth (of course). Naturally, we want this to be a backup 24/7 heat source if power/natural gas went out.

Fuel: We have a good amount of Ponderosa Pine on our property. We're near the WA/ID border, so there are other species available, but we'd start w/ our Ponderosa, I think.

 

[EatenByLimestone]

What lows are you going to see in the winter?

Considering your air sealing and insulation, and you’re looking more for ambiance and a bit of space heating, I’d think a 2 cubic foot firebox would work well. A bit smaller may be better, 1.5 or so. That could provide a good amount of heat if needed, but could be run in happy ambiance mode without too much of an issue overheating the room.

 

[gtilflm]

What lows are you going to see in the winter?

Considering your air sealing and insulation, and you’re looking more for ambiance and a bit of space heating, I’d think a 2 cubic foot firebox would work well. A bit smaller may be better, 1.5 or so. That could provide a good amount of heat if needed, but could be run in happy ambiance mode without too much of an issue overheating the room.

Here's the historical lows for the spokane area: https://www.currentresults.com/Year...ne/extreme-annual-spokane-low-temperature.php

In general, I'd say that it's common to get down to single digits for a couple weeks in the deadest part of winter. Negatives are unusual, but certainly possible.

 

[EatenByLimestone]

That’s lower than I thought you’d get, and that pushes me towards the 2cu ft stove, but your really well insulated. 2 cu ft is the safe choice. A good stove will let you burn low when you want to.

 

[begreen]

What is the output BTUs for the gas furnace?

The high ceiling is like adding another 900 sq ft. I'm leaning toward a 2.5 to 3 cu ft stove, especially if the power can go out for several days.

 

[gtilflm]

What is the output BTUs for the gas furnace?

The high ceiling is like adding another 900 sq ft. I'm leaning toward a 2.5 to 3 cu ft stove, especially if the power can go out for several days.

I believe it's a 60,000 BTU furnace.

Also, I wouldn't say the power is likely to go out for several days, but you never know, of course.

 

[njk4o5]

I have a similar setup my vaulted ceiling room with my stove is 24x28 with ~18' ceiling with R30 in Maine. The Vermont Castings Encore ~2 cu ft firebox did a very good job of heating this room, and the loft upstairs. My bedrooms at the end of the hallway did not get very warm with just the stove, due to the layout of the house. I have a huge ceiling fan in the room too, but didn't seem to make much of a difference. You will need a door at the top of the stairs to the loft, without it will be too warm to sleep up there.

I ended up selling the VC Encore just recently and got a Blazeking Ashford 30. If your just burning here and there and not really using it for primary heat a smaller stove will likely be fine, but burning wood is kind of addicting and i bet you will use it more than you think.

 

[gtilflm]

I have a similar setup my vaulted ceiling room with my stove is 24x28 with ~18' ceiling with R30 in Maine. The Vermont Castings Encore ~2 cu ft firebox did a very good job of heating this room, and the loft upstairs. My bedrooms at the end of the hallway did not get very warm with just the stove, due to the layout of the house. I have a huge ceiling fan in the room too, but didn't seem to make much of a difference. You will need a door at the top of the stairs to the loft, without it will be too warm to sleep up there.

I ended up selling the VC Encore just recently and got a Blazeking Ashford 30. If your just burning here and there and not really using it for primary heat a smaller stove will likely be fine, but burning wood is kind of addicting and i bet you will use it more than you think.

Are you saying your room dimensions are 24 ft. x 28 ft. or that the size of the Encore was 24 in. x 28 in.?

Also, my loft is open, so no option on a door. 😀 Wish we would have designed the house better, but it's a little late for that at this point.....

 

[xman23]

That's a large house, that will need a large stove. The stove location is like mine, in the corner. It provides a great view of the fire from any place in the room. The hearth has a large foot print and corner location is a good place, as typically it's not being used. Stoves have intense heat in one location. So the great room works well at giving the heat a place to go, heating up the structure. Your loft will never have any heat turned on. The ceiling fan helps with mixing the air up within the great room. I have very even heat throughout my great room. The back bedrooms will be cooler. Mine are about 5 degrees cooler. Being a new house, get the best insulation windows possible. It really helps with a wood stove at one end of the house and rooms with outside walls at the other end of the house. There is a natural air flow to my back rooms as the stove fills the great room with heat. The heat will flow high in hallway to the rooms as cold air runs along the floor back to the stove room. This is always a issue, you can't put air into a room without taking air out.

 

[gtilflm]

That's a large house, that will need a large stove. The stove location is like mine, in the corner. It provides a great view of the fire from any place in the room. The hearth has a large foot print and corner location is a good place, as typically it's not being used. Stoves have intense heat in one location. So the great room works well at giving the heat a place to go, heating up the structure. Your loft will never have any heat turned on. The ceiling fan helps with mixing the air up within the great room. I have very even heat throughout my great room. The back bedrooms will be cooler. Mine are about 5 degrees cooler. Being a new house, get the best insulation windows possible. It really helps with a wood stove at one end of the house and rooms with outside walls at the other end of the house. There is a natural air flow to my back rooms as the stove fills the great room with heat. The heat will flow high in hallway to the rooms as cold air runs along the floor back to the stove room. This is always a issue, you can't put air into a room without taking air out.

This comment was directed to me, and not @njk4o5, right?

 

[njk4o5]

Are you saying your room dimensions are 24 ft. x 28 ft. or that the size of the Encore was 24 in. x 28 in.?

Also, my loft is open, so no option on a door. 😀 Wish we would have designed the house better, but it's a little late for that at this point.....

The "great" room is 24'x28'. The VC encore is also about 24"x28" haha

 

[begreen]

I believe it's a 60,000 BTU furnace.

Also, I wouldn't say the power is likely to go out for several days, but you never know, of course.

OK, that helps. A 2 -2.5 cu ft then will likely suffice. There are several options. Is there a particular style that interests you?

 

[gtilflm]

OK, that helps. A 2 -2.5 cu ft then will likely suffice. There are several options. Is there a particular style that interests you?

Got it down to a Lopi Liberty vs. a Lopi Evergreen. Favoring the Liberty for it's larger firebox, cook top, capacity, etc. The only problem is that it doesn't currently qualify for the 30% tax credit. They're supposed to be coming out with a Liberty version that will qualify, but it's unknown when that will be at this point.

 

[begreen]

I would go for the Lopi Endeavor. It's in between the Liberty and Evergreen in size and a workhorse with a great track record.

 

[xman23]

This comment was directed to me, and not @njk4o5, right?

Yes, to OP. Just my thoughts with my house that's very similar. I now read the house is done. My loft bedroom is open with a half wall. I really makes the heating easy. With my setup -10 F is no problem heating all the house. And I like to control the temp swing as well as a thermostat. Night's are a lot of work. After 23 years we are getting lazy about running the stove all night.

 

[EatenByLimestone]

I would get the stove you want and not worry about the tax credit. It’s nice to get a great sale, but this tool/furniture will be used 6 months out of the year, every day, for 20 years. The money saved, spread over 20 years will amount to very little each year.

 

[gtilflm]

I would go for the Lopi Endeavor. It's in between the Liberty and Evergreen in size and a workhorse with a great track record.

Endeavor: It looks like the specs. are really similar to the Evergreen, but that it's .3 cu ft. larger, but the logs have to be shorter. The viewing area is smaller too, and that's something we're interested in.

 

[gtilflm]

Yes, to OP. Just my thoughts with my house that's very similar. I now read the house is done. My loft bedroom is open with a half wall. I really makes the heating easy. With my setup -10 F is no problem heating all the house. And I like to control the temp swing as well as a thermostat. Night's are a lot of work. After 23 years we are getting lazy about running the stove all night.

Yeah. The house is done. Would have done a lot of things differently but we're beyond that at this point.

We also have a half wall for the loft. What stove do you have?

 

[begreen]

Endeavor: It looks like the specs. are really similar to the Evergreen, but that it's .3 cu ft. larger, but the logs have to be shorter. The viewing area is smaller too, and that's something we're interested in.

Log length is not a big deal unless one has wood already cut longer. Standard cordwood sold length is 16" The Endeavor's firebox is more square so it can load N/S, while the Evergreen is primarily an E/W loader, which drops the real-world loading capacity significantly. One can not load the firebox fully due to concerns of the wood rolling up against the door glass as the pile burns down. A N/S loader doesn't have this issue. This is not a big deal for occasional burning, but factors into burn time when burning 24/7.

I can't decide on which Lopi model

Hey all.... Trying to pick a new wood stove. I can't seem to decide between the Lopi evergreen, endeavor or the Liberty. Thought I wanted the Rockport but I don't want to deal with the catalyst. I like the Endeavor but the Evergreen seems to have better numbers for efficiency, log size, etc. I'm...

www.hearth.com

 

[xman23]

Yeah. The house is done. Would have done a lot of things differently but we're beyond that at this point.

We also have a half wall for the loft. What stove do you have?

My stove is a Jotul Oslo Version 1. It's a non cat, cast iron. It's the dark green vittorio's enamel finish. 23 year's old and it gloss finish looks like new, not a mark on it. Well worth the few bucks. Our stove and fire is the focal point in the room. The latest Oslo 3 has a cat. You will love the stove, even if you just run it for an evening fire.

Curious, the house looked great, what would you do different?

 

[vatmark]

My stove is a Jotul Oslo Version 1. It's a non cat, cast iron. It's the dark green vittorio's enamel finish. 23 year's old and it gloss finish looks like new, not a mark on it. Well worth the few bucks. Our stove and fire is the focal point in the room. The latest Oslo 3 has a cat. You will love the stove, even if you just run it for an evening fire.

Curious, the house looked great, what would you do different?

I'm glad to hear your jotul enamel finish still looks good after all that time. We have a Jotul Oslo V2 in the majloica brown enamel that's 5 1/2 years old. Really love this stove. It is a focal point in our great room. I love the enamel finish. We have a very open floor plan with high ceilings. We don't use the stove exclusively to heat but that stove can crank out some good heat once it gets going. The room which stays colder on this floor is the room behind the stove which is the master bedroom. We are actually glad it stays colder because we like to sleep in a very cold room.