How to modernize a mid-century open fireplace

[hvmcm]

Hello all,

I hope this is the right place to post about this. I've been trying to figure out a solution for a while, so I appreciate any input you may have.

We bought a midcentury modern house a couple of years ago and we've been fixing and upgrading things one at a time. One of the things that's been quite paralyzing for me is the fireplace. It's an open fireplace, 2 chimney dampers (one on each side), 2 flues. Even though it has been swept, the prior owners neglected its care and there's creosote that needs to be cleaned as well. Its size also makes it harder to use without smoking the rest of the house. It's a beautiful fire, but it's not efficient.

We want to preserve the outer shape of the fireplace (it's trapezoidal) but would love to have a more efficient system that could help heat the house, as it gets cold in the area. Has anybody seen a solution for a fireplace like this before? We're open to using a standing stove like Rais QTEE or something like Wittus, or any other insert that may work for this case. We need to make sure the aesthetics match the architecture of the house and the fireplace, but we don't know what's possible here.

Any input or suggestions you may have would be very appreciated.
Thanks for your help.

 

[EbS-P]

What is your budget? And does it have to to be wood burning? Do you have any existing gas appliances?

 

[stoveliker]

A lot depends on the inside dimensions of the fireplace.
If an insert fits (angling the flue to one side to connect to one of the chimney channels is possible to a degree) you can add a custom bezel around it to fill the rest of the hole.

Do put an insulated liner in,.for better performance but also safety (code).
Also an insulated block off plate,.in particular if the chimney is on an outside wall.

 

[CatfishHunter]

Unless you line it and turn it into a gas insert, it's really just a relic. We have a 1950s rambler with a brick fireplace. It keeps the main room warm but causes the rest of the house to get colder. It's more ornamental than functional. We build a fire once or twice a fall/winter for fun.

We did install a nice fireplace screen & door that makes it all look nicer. It also blocks off the ugliness of the fireplace when not in use. Third bonus is that it is sealed all around so it prevents heat from escaping in the winter. From the looks of yours, I would be that you lose a lot of heat there as well.

When we bought our house (Minnesota), the local energy utility has a free "energy audit" program. They put a strong fan in the door and then closed all of our windows/doors. It allowed them to see where air was escaping and the fireplace was one of the big ones for us. You could see if your local utility provider has a similar program.

 

[hvmcm]

Thank you all for your responses. I appreciate your time.

What is your budget? And does it have to to be wood burning? Do you have any existing gas appliances?

Ideally, not more than 10-15k. But we got a quote for the creosote cleaning and that alone is about $3k (let me know if this an unreasonable quote). We don't have any gas appliances left, and we're trying to steer away from gas altogether. It doesn't make a ton of sense in our area – delivery is complicated and expensive.

A lot depends on the inside dimensions of the fireplace.
If an insert fits (angling the flue to one side to connect to one of the chimney channels is possible to a degree) you can add a custom bezel around it to fill the rest of the hole.

Do put an insulated liner in,.for better performance but also safety (code).
Also an insulated block off plate,.in particular if the chimney is on an outside wall.

This was the option we were given by a chimney sweeper. Angling the flue of an insert and connecting it to the chimney. Noted on the insulated liner and block-off plate! The whole thing is made of stone and brick, and the wall behind it is an outside wall. Given the size of the fireplace, do you think it's possible to tile the whole thing, install a standing wood stove, and seal whatever channel isn't used? That was one of the options the sweeper mentioned could work, depending on measurements of course.

Unless you line it and turn it into a gas insert, it's really just a relic. We have a 1950s rambler with a brick fireplace. It keeps the main room warm but causes the rest of the house to get colder. It's more ornamental than functional. We build a fire once or twice a fall/winter for fun.

We did install a nice fireplace screen & door that makes it all look nicer. It also blocks off the ugliness of the fireplace when not in use. Third bonus is that it is sealed all around so it prevents heat from escaping in the winter. From the looks of yours, I would be that you lose a lot of heat there as well.

When we bought our house (Minnesota), the local energy utility has a free "energy audit" program. They put a strong fan in the door and then closed all of our windows/doors. It allowed them to see where air was escaping and the fireplace was one of the big ones for us. You could see if your local utility provider has a similar program.

Yeah, that's been the issue. We only used it when the furnace stopped working for a few hours, and it didn't do much for the heat. Anywhere else in the house was colder. I believe the dampers were installed at some point due to heat leaking through the chimney, but not sure how much that changed for the house. I've been meaning to do an energy audit, maybe I should consider doing it sooner. After adding additional insulation to the roof + new windows, it must be one of the few leaky spots left in the house.

Did the screen + door do anything for you in terms of efficiency/heat? or was it just an aesthetic fix? This fireplace is hungry, it requires a lot of wood to run it on the hotter side – otherwise, things start getting smokier. It's also generally dusty, so I have to block it with the screen, or else the cats get in and fill the house with footprints.

 

[stoveliker]

This was the option we were given by a chimney sweeper. Angling the flue of an insert and connecting it to the chimney. Noted on the insulated liner and block-off plate! The whole thing is made of stone and brick, and the wall behind it is an outside wall. Given the size of the fireplace, do you think it's possible to tile the whole thing, install a standing wood stove, and seal whatever channel isn't used? That was one of the options the sweeper mentioned could work, depending on measurements of course.

In principle it is possible to install a wood stove and connect to a (inspected, and up to specs) flue.
Many wood stoves have a top exhaust though, and if your lintel is too low you'd have to either find a rear exhaust stove, or (better but may be aesthetically unacceptable) first go up with stove pipe and after a few feet turn into one of the flues. I.e. drill a hole in the current stone higher up.

The outside wall also means that if the fireplace is large enough for a stove inside there, you would really want to insulate it (rockwool, not fiberglass, with e.g. durock and tile on top of that).

Sealing a channel that's not in use is fine. Do (air) seal it from both the top and bottom. Insulation at the bottom is still best then (so you don't end up with a standing column of cold air on the sealing plate, possibly creating condensation etc.).

 

[stoveliker]

Others (begreen) have a good knowledge of stove and insert sizes. If you provide precise measurements, they'll be able to help you to see what specific models would be possible in your situation without major demo.

 

[EbS-P]

I’m going to suggest you find the biggest insert that will fit and can be installed without a surround. You won’t find anything to fill the large of a space. I left the surround off mine. The liner can be concealed by 8” stove pipe. Mine is a Drolet 1800i
Same parent company but bigger. https://www.englander-stoves.com/us/en/heaters/wood-inserts/esw0014/

You will have to come off at an angle with the liner. I was trying to find something more rectangular but it’s hard to know how integral the surround is and how it would look without it. If you have enough height a stove is an option but I think the plain black box may actually look better that stove.

Get it cleaned and measured and then go from there. 3 k for a cleaning is a lot. I’d shop around.

 

[stoveliker]

if the chimney needs chemical cleaning, 3k is reasonable I think.

 

[CatfishHunter]

Thank you all for your responses. I appreciate your time.


Ideally, not more than 10-15k. But we got a quote for the creosote cleaning and that alone is about $3k (let me know if this an unreasonable quote). We don't have any gas appliances left, and we're trying to steer away from gas altogether. It doesn't make a ton of sense in our area – delivery is complicated and expensive.


This was the option we were given by a chimney sweeper. Angling the flue of an insert and connecting it to the chimney. Noted on the insulated liner and block-off plate! The whole thing is made of stone and brick, and the wall behind it is an outside wall. Given the size of the fireplace, do you think it's possible to tile the whole thing, install a standing wood stove, and seal whatever channel isn't used? That was one of the options the sweeper mentioned could work, depending on measurements of course.


Yeah, that's been the issue. We only used it when the furnace stopped working for a few hours, and it didn't do much for the heat. Anywhere else in the house was colder. I believe the dampers were installed at some point due to heat leaking through the chimney, but not sure how much that changed for the house. I've been meaning to do an energy audit, maybe I should consider doing it sooner. After adding additional insulation to the roof + new windows, it must be one of the few leaky spots left in the house.

Did the screen + door do anything for you in terms of efficiency/heat? or was it just an aesthetic fix? This fireplace is hungry, it requires a lot of wood to run it on the hotter side – otherwise, things start getting smokier. It's also generally dusty, so I have to block it with the screen, or else the cats get in and fill the house with footprints.

Depending on the location, your fireplace probably will not heat your entire house. Most of these are ornamental in nature, not intended for whole-house heating like in the past. Our cabin is an A-frame so essentially all one big room. The wood stove there keeps us nice a toasty on winter trips even when it's -40F out there. At our city home two years ago, our furnace died on Christmas eve. I ran a fire all night until morning and then collected space heaters from friends and neighbors to keep the rest of the house warm. It was -10F so I had concerns about freezing pipes. Once I plugged in all of the heaters, I stopped using the fireplace. I didn't want the scant heat that we had to go up the chimney.

The fireplace door that we installed did help with efficiency. I didn’t measure anything, but no longer feel a draft from that area. If I had cats, it would keep them out of the fireplace too!

 

[FireplaceTreatments]

If you decide to do glass doors, they can be made to fit like you see below. They can also have fixed glass panels on the sides instead of a full metal frame.