To Stove or Not to Stove?... for heating!

[Fezatron]

Hi all. I’m a newbie here so please be gentle!

I want to install a stove but I’ve run into a problem and I hope you guys can help me sort it out. I have an existing internal masonary fireplace ( the back of the fireplace and chimney back onto a wall of a bathroom behind it. One salesman tells me if I install the stove inside the fireplace I will only get about 12% efficiency as heat rises and all the heat will disappear up and out of the chimney. He advised that putting in a lower block off plate at the base of the chimney made of compressed cement sheeting and topped with some kind of insulation would have little effect and I’d be wasting my money. He says I should only consider an inbuilt fireplace with a fan and that will bring efficiency up to around 65%.

Some background. The house is old ( built in 1950’s?) and not very thermally efficient at all. Has some ornate plaster ceilings, lead light glass and coloured glass and that’s why we wanted a fancier (IMO) stove rather than a plain inbuilt fireplace. We had chosen the Jotul F 8 as a stove before the salesman threw a spanner in the works.

So we have a few problems : If we bring the Jotul into the room and use the back flue hole and run the flue into the fireplace horizontally and then up the chimney I won’t be able to mount a TV on the chimney above the fireplace as it will get too hot. But I guess this would sort out the heating problem? Also the room the fireplace is going in is small (3.7m x 3.7m x 3.25m high) so the stove would take up valuable real estate. But the stove/fireplace still needs to be able to heat the rest of the house.

The misses likes the look of the cast iron stove and not the inbuilt option and you know what they say : happy wife happy life!

Any thoughts welcomed.
Thanks in advance.

 

[begreen]

Welcome. What is "the stove" make and model? It sounds like a freestanding Jotul, but not sure. Have you already purchased it? If not, are you opposed to getting a modern insert to go into the fireplace instead? Some are made with classic, cast iron fronts that are eye pleasing, though I am not sure if they are sold in your country.

The salesperson is incorrect. Block-off plates are effective. A freestanding stove with a proper, insulated block-off plate can indeed heat well if it is properly set up. However, it really helps to have a stove with a blower in order to convect the heat better. But seeing this is an interior fireplace and chimney, there will be some heat coming off the masonry over time as it is heated up by the radiant stove.

 

[Fezatron]

Hi begreen. Thanks for your reply. The only info I have about the stoves make and model is that it’s a Jotul F8. I’ve added some pics of its dimensions and characteristics to see if that helps. It has a peak output of 17kW.
I’ve since found an inbuilt fireplace that has a cast iron surround with a classic design but really wanted that stove with a TV above it.

How would you build an effective block off plate? What materials would you use,etc? Do you think this stove would be effective if it was placed inside the masonary fireplace and had its flue coming straight up?


Cheers

 

[stoveliker]

Also remember that a stove is a space heater in first approximation. Putting it in a small room like that will require to get some major fan help in getting at least some of the heat to the rest of the home.
And the room will be quite hot...

If you can make a looping airflow (i.e. you can walk a circle in your home through different rooms), that would help. A floor based box fan blowing colder air to the stove room would be needed.

 

[begreen]

Hi begreen. Thanks for your reply. The only info I have about the stoves make and model is that it’s a Jotul F8. I’ve added some pics of its dimensions and characteristics to see if that helps. It has a peak output of 17kW.
I’ve since found an inbuilt fireplace that has a cast iron surround with a classic design but really wanted that stove with a TV above it.

How would you build an effective block off plate? What materials would you use,etc? Do you think this stove would be effective if it was placed inside the masonary fireplace and had its flue coming straight up?


Cheers
View attachment 279392View attachment 279393View attachment 279394

The F8 was the predecessor to the F400 Castine in the states. It is a competent, 11kW peak stove, but somewhat old tech as far as efficiency goes. It also lacks a blower option. A radiant stove like the F8 will work, just not as well as a convective stove with a blower.

There are many threads on building a block-off plate and also a couple of articles. The most common design uses sheet metal. Here's an article to get you started:

Why damper seal is needed, block off plate install

Should fireplace inserts and hearth stoves have a metal sealing plate installed at the damper area? Here is the simple answer. It is almost impossible to correctly seal most insert panels to the fireplace front. A lot of air can get through them - this works both ways.....hurts the draft when...

www.hearth.com

 

[begreen]

What is the size of the fireplace opening and depth? Have you looked to see if the Lopi Rockport or a PE Alderlea (T4 or T5) would fit? They have a blower option. The Alderleas are also available in inbuilt models.

Also, the room is small for a wood stove so it's important to know how open is the fireplace room to the rest of the house. Is the general floorplan open or closed off by doorways? If heat will not easily convect to other parts of the house, this room may get too hot in the mild climate of NSW.

 

[JaroMato]

What about a rumford fireplace instead of the insert?

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[begreen]

I think the fireplace is already in place. A Rumford can radiate more heat, but most is lost up the chimney, especially as the fire dies down and it's not clean burning at all.

 

[Fezatron]

Hi everyone. Thanks for the responses guys.

I’ll try and go in order of responses to provide some clarity.

The fireplace room is pretty much in the middle of the house with everything else coming off it and the room adjacent to it and a loop isn’t possible. A couple of strategically placed fans wouldn’t be the worst thing in the world.
Lopi Rockport and Anderlea T5 and too big I think plus the Rockport is a little over my budget. However the Anderlea T4 might do the trick perhaps. I need to do some more research. My house is roughly 160m^2 (1700 sq ft) I think. Adjacent to the fireplace room is the kitchen/family room about 7m x 5.3m x 3.25m high joined by a double sliding door approx. 1.77m x 2.05m. Everything else comes off these 2 rooms and is all doors and hallways. The size of the current hole for the fireplace is 700mm wide x 760mm high and 500mm deep. I can renovate the hole to about 1.12m wide or slightly bigger and I think that’s what the installation requires. However I’m not sure of the height requirement yet to the top of the fireplace and then mantle. But the depth may be a problem as I want the TV above the fireplace and I’m worried rising heat would destroy a TV mounted above.
I’m not interested in an open fireplace as I want to have a TV above the fireplace. This is an important factor to me in utilising the space to its fullest capacity.

A good tactic for me if I get the T4 and it gets too hot could be to just turn off the fan as well as open widows/doors. What are your thoughts on this models size vs space? I saw the T4 on YouTube and it looked like a hardwired fan. The good news is a local business sells the T4 so I’ll go and see if they have any in the showroom.

Cheers

 

[Fezatron]

Oh and I forgot to add that the installation manual for the T4 says the minimum clearances can be reduced if surrounded by non- combustibles but I’m still trying to find out what those clearances are.

Cheers

 

[begreen]

The T4 sounds like a better fit. You are in a mild climate and the heat is going to want to stay in the room. A ceiling fan will help a bit. Is there a mantel on the fireplace? That could be a clearance issue unless it's non-combustible. Can you post a picture of the current fireplace wall?

 

[Fezatron]

A ceiling fan is definitely going in when the electrician comes. There is no mantle on the fireplace currently. I took it down when I pulled the inset out. It was at the join between render and tiles which was about 1.14m above floor level. As you can see I’ve got some work to do. I was goin to re-tile the bottom section if it worked out the mantle was about there but depending on it’s location I might have cement render all of the lower section? But I was going to put in a great lump of wood for a mantle maybe 8 inches deep in the fireplace sticks out from the space. I should say the 500mm depth is when tiles are added at the bottom to bring the front level with the top rendered section. Here are some pics. In the 1st pic you can see to the right some French doors. When I bring the hearth up to fireplace level that may interfere with the flow of the room. Also found some old gas pipes after pulling out the insert! Arrrrrrgh! Lol.

 

[JaroMato]

i am not sure if this has been said yet.

have you considered dismantling the brick surround?
Does that chimney continue to be brick all of the way up to the roof?

To me it seems like you are spending a bunch of energy to work around what is currently not working very well.

 

[begreen]

A ceiling fan is definitely going in when the electrician comes. There is no mantle on the fireplace currently. I took it down when I pulled the inset out. It was at the join between render and tiles which was about 1.14m above floor level. As you can see I’ve got some work to do. I was goin to re-tile the bottom section if it worked out the mantle was about there but depending on it’s location I might have cement render all of the lower section? But I was going to put in a great lump of wood for a mantle maybe 8 inches deep in the fireplace sticks out from the space. I should say the 500mm depth is when tiles are added at the bottom to bring the front level with the top rendered section. Here are some pics. In the 1st pic you can see to the right some French doors. When I bring the hearth up to fireplace level that may interfere with the flow of the room. Also found some old gas pipes after pulling out the insert! Arrrrrrgh! Lol.

Thanks for the pictures, they are a big help. Whatever stove is chosen, check the mantel requirements closely. It could get sticky with the Alderlea T4 because there is no tested data for clearances to a mantel. It is not normally installed in a fireplace. However, it the new mantel is non-combustible, then no clearances issue. In the US there are several good quality non-combustible mantel companies. Their products very much like real wood. Are there any in NSW?

 

[Fezatron]

Hi JaroMato and begreen.

Demolishing the fireplace is definitely not a consideration. I’ve already demolished one in the house and there was about 3 tonne of bricks. This one is way bigger and I think there’s probably 5 tonne of bricks in this one. Coupled with the soot and patching the roof and ceiling I think it’d be a nightmare! Plus I want a TV above it.
I haven’t considered a different mantle yet as I was always going to use timber so I’ll have to look into that further. I found an Alderlea T4 on a different stores website installed in a similar fashion to what I was thinking so I might contact them and ask what clearances they used.

 

[Fezatron]

Update : After racking my brain for another couple of hours over this and in the interests of exploring all options I’m beginning to think that JaroMato may be right. As the depth of the current fireplace isn’t sufficient for the type of wood stove/heater I want I’m investigating the demolition of the current fireplace and installing a freestanding stove/heater and simply putting a TV next to it. A massive increase in work from what I was expecting. If I go down this path I think it’s fair to say that I’ve well and truly opened a can of worms......if I haven’t already! Lol

 

[clancey]

That's a hard decision to make especially when it seems to be a working fireplace with no safety issues. The personality of a house is important too and some decisions are just downright hard to make and if it were a safety issue and not trusting it in the future heck I would take the week to have it tore out. It will change your whole house and the problem of figuring things to make do now will be gone...Just think---hard work---plenty of trash and bricks--and a brand new adventure...Interesting thread and we all go back and forth with these major decisions but once you make the decision it gets easier from there because there are many decisions behind that one and just think some "brand new unknown ones" thanks for the posting. Mrs clancey

 

[EbS-P]

Update : After racking my brain for another couple of hours over this and in the interests of exploring all options I’m beginning to think that JaroMato may be right. As the depth of the current fireplace isn’t sufficient for the type of wood stove/heater I want I’m investigating the demolition of the current fireplace and installing a freestanding stove/heater and simply putting a TV next to it. A massive increase in work from what I was expecting. If I go down this path I think it’s fair to say that I’ve well and truly opened a can of worms......if I haven’t already! Lol

I like my cast iron Jotul F400 set in my fireplace. It’s is as far back as it can go but the stove could move back but the liner is preventing it moving further back. Some Jotul models have short leg kits. My opening is .75 m high by 1m wide. (I think I did all my conversions correctly)

Making sure you adhere to clearance to combustibles looks like your biggest job. And should be addressed not matter what you chose if you are burning in it.

I kept my tv above the fireplace. If I had it flush mounted it won’t get too hot but the stone behind the tv can get up to 38c after a long day of burning. My blockoff plate is not well sealed and I don’t have insulation above it. My stove heats 95 m^2 open concept easily and another 90 it keeps livable, but my climate is pretty mild -4 C is a cold night. Keep researching the best solution. I’m sure there is one available you just might not like the cost or the work it would require.
Evan

 

[begreen]

I haven’t considered a different mantle yet as I was always going to use timber so I’ll have to look into that further. I found an Alderlea T4 on a different stores website installed in a similar fashion to what I was thinking so I might contact them and ask what clearances they used.

View attachment 279449

The code legality of that install is dubious for here in the states. Not sure what is required in Australia.

 

[begreen]

I like my cast iron Jotul F400 set in my fireplace. It’s is as far back as it can go but the stove could move back but the liner is preventing it moving further back.

That non-combustible mantel works well and looks good too.
Here are some other non-combustible mantel options.

Non-combustible mantels

Starting a thread for folks that are looking for non-combustible mantels. These are very realistic, but made from concrete: http://magrahearth.com/natural-wood-series-gallery MagraHearth website http://magrahearth.com/

www.hearth.com

 

[MR. GLO]

What about a rumford fireplace instead of the insert?

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how much was that? very nice!