improve efficiency of gas fireplace?

[JASinIL2006]

Hi all, we have a natural gas-powered fireplace in our basement, installed by a previous owner. The fireplace is one of those 'cool' 1960's conical style fireplaces, sort of like this one:



For reasons I can't really explain, I kind of like this old fireplace and I don't want to get rid of it. My problem is that the fireplace does not do a great job of heating the space, despite kicking out some serious flames... I think a lot of the heat goes right up the flue into the chimney. We try to adjust the damper to keep all the heat from going up the pipe, but I worry a bit about closing it too far.

Any ideas for increasing the efficiency of this kind of fireplace? I don't really want to spend an arm and a leg, and I'd like to keep it because I enjoy its funky styling, but if we could get it to keep more heat in the house, I'd be a happy camper.

Thanks,
Jim

 

[WIMUSKY]

Re: improve efficiency of gas fireplace?

I'd keep it if you don't have a secondary heat source. I believe they make a box with a fan that takes the heat going up the flue and blows it in the room...... Heat exchanger I believe......

 

[rbh]

Re: improve efficiency of gas fireplace?

My folks have one of those acorn style fire places, more for show than anything.
Replace with an airtight, ensure your chimney passes code for insurance purposes.

There is always pellet stoves as well, if getting fire wood is an issue.

 

[gm280]

Re: improve efficiency of gas fireplace?

First thing you absolutely have to do if you already haven't done already is buy CO detectors and install them on every level of your house! You can't smell CO and therefore would never know if there were any problems. You are correct that a lot of fire places do sent most of the heat straight out the chimney AND draw a lot of the home heat with it too. Some after market heat type exchangers could help. They collect the heat and a fan sends it back into the room. They help a little...

 

[Georgesalmon]

Re: improve efficiency of gas fireplace?

We had something called a "heat-a-later" I think. Already described above, a square box with tubes in it and a fan. Just cut the flue to install, and it did scavenge a bunch of heat from the flue. So much we had to plug it into a 110v thermostat to shut it down or the heat would drive you out.

 

[JASinIL2006]

Re: improve efficiency of gas fireplace?

Thanks for all the suggestions, I'll look for a heat exchanger box for the flue.

Also, we already have CO detectors as well as smoke detectors. I think in IL it's the law (in addition to being a good idea).

Thanks again!

Jim

 

[agallant80]

Re: improve efficiency of gas fireplace?

You can change the logs in it for about $100-$300. Some of the logs require a chmini like you have and other logs are "direct vent" where they are safe enough to vent in to the living space because they burn all of the fuel and put all of the heat in to the living space. Any ways with the age of that thing I would replace the logs, any logs made after (don't remember but some time in the early 80s) require a Oxygen Depletion Sensor which will turn off the gas.

 

[bigdee]

Re: improve efficiency of gas fireplace?

Problem with masonry fireplaces is they are like a giant heatsink. Until they get warm they soak up much of the heat. Good news is they give off some passive heat. The flu is also a big factor,you could get unvented logs and close off the flue completely. All newer gas logs have a built in co safety cut off. Best bet for efficiency though is a gas space heater and only use the fireplace for looks.

 

[JASinIL2006]

Re: improve efficiency of gas fireplace?

Not a masonry fireplace; it's a free-standing metal unit. (See picture in post #1.)

I hadn't thought about replacing the logs.... the current model has a big gas pipe with holes that is buried in some lava rock, beneath some comically un-realistic looking ceramic logs. So changing out the guts might a possibility?

 

[Limited-Time]

Re: improve efficiency of gas fireplace?

Problem with masonry fireplaces is they are like a giant heatsink. Until they get warm they soak up much of the heat. Good news is they give off some passive heat. The flu is also a big factor,you could get unvented logs and close off the flue completely. All newer gas logs have a built in co safety cut off. Best bet for efficiency though is a gas space heater and only use the fireplace for looks.

What he said ^^^^

 

[aspeck]

Re: improve efficiency of gas fireplace?

I like the new logs idea and the heat exchanger on the flue. I have 2 gas fireplaces, both are vented. One has a heat exchanger built in and gives us about 30,000 Btu's of heat. The other does not, and we get about 15,000 Btu's of heat from it. I have looked at ideas for a fan to be installed on a thermostat, to up the heat exchange factor of the less efficient fire place. The difference in the 2 units, the 30,000 Btu is our primary heat source for our dining room. The "smaller" unit is back up heat and looks in our living room.

 

[bruceb58]

Re: improve efficiency of gas fireplace?

If you close off the flue, aren't you going to have CO issues?

 

[aspeck]

Re: improve efficiency of gas fireplace?

If you close off the flue, aren't you going to have CO issues?

Very possible, but it depends on the logs he would get. Under the current set up, ABSOLUTELY! Don't do it! But a trained technician could convert his unit to a ventless one. The problem with ventless units is the amount of moisture that the burning gas gives off. Burning gas gives off A LOT of water! I cannot leave the gas wall heater on in my garage because then I have a moisture problem. Only when needed does it get used. Same with my ventless wall unit in my basement ... only when needed or I have a moisture issue. Just some different things to ponder ...

 

[bruceb58]

Re: improve efficiency of gas fireplace?

The problem with ventless units is the amount of moisture that the burning gas gives off. Burning gas gives off A LOT of water!

Must be similar to how the condensing HVAC furnaces work?

EDIT: Been reading a little about them(ventless fireplace). Not sure I would put one in my home.

 

[bigdee]

Re: improve efficiency of gas fireplace?

Very possible, but it depends on the logs he would get. Under the current set up, ABSOLUTELY! Don't do it! But a trained technician could convert his unit to a ventless one. The problem with ventless units is the amount of moisture that the burning gas gives off. Burning gas gives off A LOT of water! I cannot leave the gas wall heater on in my garage because then I have a moisture problem. Only when needed does it get used. Same with my ventless wall unit in my basement ... only when needed or I have a moisture issue. Just some different things to ponder ...

For each pound of propane you burn it gives off 1.6 pounds of water! I heat with 2 ventless propane space heaters, 70,000 btu total ( I also have electric heat) and I have trouble with windows condensating on the inside. On the plus side I don't need a humidifier! Ventless=99% efficiency , vented through a flue=80%.