Adding to an existing fireplace

[Stir224]

Hi all. I currently heat (most of the house) with a medium sized insert in a masonry exterior chimney. House is 2000sqft 2 story built in 1976 with new windows and updated attic insulation. First floor is decently open second floor is not. It’s no where near tight but I have trouble believing it’s the worst house on the block insulation wise. With the Century 2900 insert we use now we really start to struggle with anything over a 35-40 degree temperature difference. The stove burns exactly how I think it should but I’m just not sure it has enough firepower to heat the whole house through a northeast winter on its own. We are burning mostly silver maple with some ash this season and will have mostly oak ready next year so I’m not sure if that will help in producing more heat. My goal is to heat 100% with wood with no issues. Am I being crazy thinking it’s possible? Or is it just not going to happen with this house?

Anyway on to my question. Our fireplace is raised about 9 inches off the ground. I’m playing with the idea of would it be possible to build an extension of bricks on front of the stove to place a larger free standing stove. The subfloor is a poured slab. I would like to go with a blaze king princess or king stove just based on what I read about them. People seem to have amazing things to say about these. I would run the chimney straight up and out the roof alongside the current masonry chimney. Has anyone ever seen anything like this done before? I’ve searched and searched but can’t seem to find the right keywords. I’m not really sure it’s the most cost effective option but I wanted to at least do some research.

 

[Stinkpickle]

Maybe extend the hearth, put a rear vented stove on it, and run the liner directly up the existing chimney? It would definitely be warmer than a 35-40 degree difference in that room. Something like this...

 

[Stir224]

Maybe extend the hearth, put a rear vented stove on it, and run the liner directly up the existing chimney? It would definitely be warmer than a 35-40 degree difference in that room. Something like this...

Thanks so much for the reply! Yeah definitely looking at rear vent stoves but the only ones I’m familiar with are Vermont castings which can be on the pricier side for sure. Do you have any other recommendations for larger rear vent stoves?

Also I should have clarified. We can do probably 50 degree delta in the stove room at most but the rest of the house doesn’t quite keep up with that (I would never expect it to). I understand it’s a space heater and the limitations that come with it. I guess I’m looking for someone to tell me I’m crazy and you really can’t get much better deltas with a slightly older house.

Edit: I should also add fireplace opening is 34” wide and 31” tall

 

[Stinkpickle]

Look at Woodstock Soapstone Progress Hybrid.

 

[begreen]

I'm wondering if this is an issue of heat distribution. Does the room where the insert is heat up well throughout the winter? How hot do you like the house to be?

 

[Stir224]

I'm wondering if this is an issue of heat distribution. Does the room where the insert is heat up well throughout the winter? How hot do you like the house to be?

I was suspicious of this as well but using fans I can generally keep the entire house within 10 degrees of the warmest room. When the stove first gets cooking sure the insert room is probably the hottest by a good margin but it doesn't take long to make its way throughout the house. Maybe an hour or so. Sometimes less. The insert is in the family room and pointed directly to a pretty open kitchen and living room which are directly behind me in the picture.

This might be where I think I'm running into issues. Wife likes it warm. Like below 70 she starts complaining. So to answer your question in an ideal world I'd like to be able to keep the first floor (for the most part) above 70. The second floor we like it a bit colder so I'm less concerned about that. Half the house is on top of a half finished basement. I've got about half the rim joists sealed and then going to add fiberglass rolls to the basement ceiling because there is currently no insulation between basement and first floor. I expect that will make somewhat of a difference.

 

[begreen]

I've got about half the rim joists sealed and then going to add fiberglass rolls to the basement ceiling because there is currently no insulation between basement and first floor. I expect that will make somewhat of a

The heating requirements are reasonable. If the family room is in the basement and it is still unfinished, that is where to put the $$. Uninsulated basement walls soak up a lot of heat, up to 1/3 of the heat produced. The CW2900 puts out a lot of btus so reducing heat loss may provide faster gains and greater comfort.

 

[Stir224]

The heating requirements are reasonable. If the family room is in the basement and it is still unfinished, that is where to put the $$. Uninsulated basement walls soak up a lot of heat, up to 1/3 of the heat produced. The CW2900 puts out a lot of btus so reducing heat loss may provide faster gains and greater comfort.

Whoops that might have been confusing. The family where the stove is is on the first floor over a slab. The kitchen and living room are also on the first floor but those are over a (currently) un insulated basement.

It seems to be like it has to be 1 of 3 ish things.

1. Stove isn’t big enough (least likely I think)
2. Wood is not ideal. Both species and dryness
3. Still losing considerable heat somewhere/air leaks

I’m working on 2 and 3 by adding insulation in the basement and have several cords of red oak that will be ready next winter but figured I would ask my original question to see if it was normal to need a bigger stove and how I would do that.

For anyone that might search for this in the future and find this thread first here are a few helpful links to get you started that I was able to find

Extend a raised hearth to pass code

Hi everyone, I’m new to the forum. I recently ran into a problem when trying to pass rental code inspection for a house we bought that was built in the 60s. We were told the hearth is too narrow, it currently measures at 12 inches and code requires it to be at least 20” if I remember correctly...

www.hearth.com

Using a Granite Raised Hearth Extension for wood burning fireplace - what materials?

I have a masonry wood burning fireplace (not prefab) on a concrete slab. We hammered off the ugly 12 inch high brick bench and want to replace with a half-step hearth for (6 inches final height) with a 1 inch granite top. The firebox is raised 12 inches above slab level. I've read fireplace...

www.hearth.com

 

[Stir224]

I took a look at both the Hearthstone Mansfield and the Woodstock progressive hybrid. Boy that PH is a nice looking stove. Seems like a lot of people have really good things to say about it as well.

On an unrelated note, my goal for every fire is to work the air control closed as much as possible without snuffing the fire out. Am I wrong in this mindset? Do I gain advantages by leaving it further open? Just seems to me like I’m sending more heat up the chimney

 

[DuaeGuttae]

You could extend your hearth and put the pipe straight up if your second level configuration allows it. We looked at that but had plumbing in our ceiling, so it was more complicated.

Since you already have a nice insert that is doing a pretty good job overall, is there another spot in your home where you could add a freestander? That would seem to be the easiest way to increase your BTU output and improve heat distribution. You wouldn't have to use both stove simultaneously most of the time, but you would have the option.

Yes, you want to reduce primary air to the point where you have good secondaries burning the smoke and producing the heat.

 

[Stir224]

You could extend your hearth and put the pipe straight up if your second level configuration allows it. We looked at that but had plumbing in our ceiling, so it was more complicated.

Since you already have a nice insert that is doing a pretty good job overall, is there another spot in your home where you could add a freestander? That would seem to be the easiest way to increase your BTU output and improve heat distribution. You wouldn't have to use both stove simultaneously most of the time, but you would have the option.

Yes, you want to reduce primary air to the point where you have good secondaries burning the smoke and producing the heat.

Either extending the hearth at its current raised level or deleting the raised hearth all together are the two options I am looking into. We do have a second floor but none of it is above the stove kind of like a split level house almost. Would be pretty easy to run a chimney straight up. Probably going to start with the cheap stuff first and go from there

 

[begreen]

Is the CW2900 the largest insert that would fit into the fireplace or is there a lot of room behind it? If a bigger insert could be installed there are some that are one-third larger and that will put out more heat. One with a square firebox would afford fuller N/S loadings too. Do you have the fireplace dimensions?

 

[Stir224]

Is the CW2900 the largest insert that would fit into the fireplace or is there a lot of room behind it? If a bigger insert could be installed there are some that are one-third larger and that will put out more heat. One with a square firebox would afford fuller N/S loadings too. Do you have the fireplace dimensions?

31hx34wx32d (to the very edge of the hearth. Firebox itself is only about 16d). I looked at larger inserts but none seem to qualify for the new tax credit in 2021 of 75% HHV or greater

 

[begreen]

Close, but not quite, unless the 16" depth is at lintel height and not the bottom. A square firebox insert that can take 16-18" splits N/S is going to need more like 18-20"

 

[Stir224]

It is at the top center of the firebox (shallowest point) which I believe is the lintel I've never actually heard that term before. The firebox is not square it had slight tapers inwards on both the back and sides. The 2900 is just over 26" deep and it fits with about 7 inches left on the hearth.

 

[begreen]

The lintel is the supporting steel at the top of the fireplace opening. What is the depth at the firebox floor?

 

[Stir224]

I was going off of memory which appears to be fading as I age. I just remeasured it and to the front side of the bricks resting on the lintel is about 20" deep. I can't get to the base at the moment. The insert is running full blast and there is insulation tucked between it and the sides of the firebox but the taper is not that big. I don't think its much more than it is at the top.

 

[begreen]

Then it sounds like the 75% efficiency issue is the main problem. Many are rated at 74%.. Based on the process of elimination in inserts that leaves the BK Princess insert. The firebox is about 25% larger than the CW2900. Peak BTUs may be lower, but the Princess will produce a more steady output over the length of the burn. Or for more heat output there is the 3.0 cu ft FPX (Lopi) flush large hybrid.

 

[Stir224]

Good to know. I called a few places last week to check on the prices for Princess inserts and was getting around $3500-$4000. Does that seem about right?

Also I think the princess firebox is 2.6cf and the cw2900 is 2.4cf so ~10% more wood?

 

[begreen]

Not sure about current pricing. It sounds a little high, but this is peak season and we are in WA state, so low shipping costs for BK and Lopi (FPX) products.

 

[Stir224]

Not sure about current pricing. It sounds a little high, but this is peak season and we are in WA state, so low shipping costs for BK and Lopi (FPX) products.

Yeah I thought so as well. Figured at that price just get a heartstone or woodstock and build the hearth for it. They are way nicer to look at IMO.

 

[begreen]

Yeah I thought so as well. Figured at that price just get a heartstone or woodstock and build the hearth for it. They are way nicer to look at IMO.

The FPX Flush large hybrid would look nice there, but it would need the blower running to move the heat.

 

[kellnoon]

We heat our 3000 sq foot house on just Woodstock ideal steel stove through Vermont winters.. Only the basement (counts for around 900 sq feet) gets heat from the boiler. We have 15 foot ceilings and run two ceiling fans.

s for

 

[Stir224]

We heat our 3000 sq foot house on just Woodstock ideal steel stove through Vermont winters.. Only the basement (counts for around 900 sq feet) gets heat from the boiler. We have 15 foot ceilings and run two ceiling fans. View attachment 271074s for

Wow that’s a lot of heat! How is the heat loss in your house? Modern insulation?

 

[Stir224]

Well as an update I may have gone a little crazy with the air sealing. I’ve been having some troubles damping fires all the way down even when it’s really cold out (25 and below) when just a few weeks ago the fire was ripping hot. My wood is slightly wet (21-22% ish) so I thought that might be the issue so I picked up some kiln dried wood and it took off like crazy but as I damped it past 80% it started to go out. I opened the sliding door and sure as hell the probe temp started climbing again. Closed the door and it started dropping. Opened it and it climbed.

Sucks cause I can’t really do an OAK. The insert is in a masonry fireplace and sitting on top of the ash dump.

Guess I’ll have to suck it up and put in a freestander! Oh well!