First Season Heating w/ EPA Insert, Disappointing Results- Tips?

[riles246]

Last spring I installed an EPA insert in my old zero clearance fireplace with plans to supplement my heat in the winter and keep my electric bills down in the coldest months. My primary heating system is an air source heat pump, so my entire energy cost comes in through the electric bill. The insert is a Regency Alterra CI1150, rated for 70% HHV efficiency, but does not have fresh air intake and is non-catalytic. I use the fan on "auto" setting, sometimes on low and sometimes on high. If I'm home when I'm running it, I use full air and high fan, but if I'm in and out I set it for a longer burn at about half air and low fan.

Last winter, before getting the fireplace, I used 7.7k kwh in Nov/Dec/Jan to run the house (heat + all other electric). This year, I burned 1.5 cords of wood so far, and have used 8.5k kwh. There is a tangible increase in electricity usage (i.e. heat pump usage) when I use the fireplace. Now, it's not all bad- the room that has the fireplace is a toasty 73F when it's running, as compared to 68F when I use the heat pumps. But given that I'm able to raise the rest of the first floor by 1F when the fireplace is running (indicating that the fireplace is assisting the rest of the house), I would have expected overall heating utilization to drop.

I'm thinking two things- 1. lack of fresh air intake is causing me to suck cold air into the house in other rooms, and the heat pumps are heating that air before it gets burned by the fireplace, or 2. I just really need a better system for circulating heated air. On #1, I'm running an experiment in February where I'm leaving the window closest to the fireplace cracked all month, so I'll know in a couple weeks if that made a difference. On #2, I can install a duct from the ceiling of this room to the floor of my second story, and can put a ducted fan in to blow cold upstairs air to the fireplace room in hopes of circulating better. Right now I just use two fans, one blowing cold air into the room and one in the room blowing out the other doorway, creating a bit of a circle around my first floor.

But overall, I'm just at a loss as to what is happening. The room, and parts of the house, are tangibly warmer, but the energy usage is tangibly higher. I know that it's not other factors- I've confirmed that the temperatures outside are, on average, similar, and that my other usage is not noticeably different.

Any suggestions welcome!

 

[brenndatomu]

If I'm home when I'm running it, I use full air and high fan, but if I'm in and out I set it for a longer burn at about half air and low fan.

Your air setting is awfully high...best efficiency is with the air set low...0-25% range...you are sending half your heat up the chimney...and the higher its set, the more cold make up air is being pulled into the house too, double whammy.

 

[bholler]

Plus all of the air being pulled through the zero clearance box and chimney to cool it. What fireplace is the insert installed in? Does it have a full insulated liner? Are the ventilation grilles on the fireplace obstructed at all?

 

[riles246]

Plus all of the air being pulled through the zero clearance box and chimney to cool it. What fireplace is the insert installed in? Does it have a full insulated liner? Are the ventilation grilles on the fireplace obstructed at all?

It's an old Majestic fireplace from the 70's. I don't know if it's actually "zero clearance" but it is installed in a wall chase with framing very close (but not touching) the fireplace. Nothing insulated that I'm aware of, gets freezing cold when no fire is running. I think the ventilation grilles are sort of obstructed- they come in from the top on what is now the area between the front of the insert faceplate and the insert itself. But I assume that the insert is designed with this in mind? Not sure. The dealer said that this insert was suitable for my fireplace but that's about all I know- I didn't press him on it because I was excited to be able to use an insert instead of spending $15k on destroying the wall to change to a new fireplace.

Good to know on the air setting- I figured the efficiency would be higher with a hotter fire but clearly I had it backwards. Will try running with a lower air setting as well. On the lowest setting the fire all but goes out, but just off of the lowest setting it's able to sustain the fire.

 

[bholler]

It's an old Majestic fireplace from the 70's. I don't know if it's actually "zero clearance" but it is installed in a wall chase with framing very close (but not touching) the fireplace. Nothing insulated that I'm aware of, gets freezing cold when no fire is running. I think the ventilation grilles are sort of obstructed- they come in from the top on what is now the area between the front of the insert faceplate and the insert itself. But I assume that the insert is designed with this in mind? Not sure. The dealer said that this insert was suitable for my fireplace but that's about all I know- I didn't press him on it because I was excited to be able to use an insert instead of spending $15k on destroying the wall to change to a new fireplace.

Good to know on the air setting- I figured the efficiency would be higher with a hotter fire but clearly I had it backwards. Will try running with a lower air setting as well. On the lowest setting the fire all but goes out, but just off of the lowest setting it's able to sustain the fire.

The insert may say it's ok but I really doubt your fireplace does which means an insert never should have been installed in there. And the air cooling vents on the fireplace and the chimney absolutely need to be completely unobstructed. That is what keeps the metal box cool so the wood is safe that close

 

[tabner]

How many sq ft is your house, and what year was it built?

As far as your two ideas. I am not a huge fan of #1 (cracked window), as long as the fireplace is not struggling to burn or back drafting, etc, i don't think this is necessary, and isn't going to help (someone could correct me as I may be wrong here). #2 is a good idea i think. I have this in my house, and it definitely gets the air around more.

 

[riles246]

The insert may say it's ok but I really doubt your fireplace does which means an insert never should have been installed in there. And the air cooling vents on the fireplace and the chimney absolutely need to be completely in obstructed. That is what keeps the metal box cool so the wood is safe that close

I guess I just don't know whether they are obstructed since I can't see behind the front face plate. The only thing I can check is that the wall chase still feels cold to the touch when it's running (the backside of the chase is in the garage so I can feel it and it's still cold).

 

[bholler]

I guess I just don't know whether they are obstructed since I can't see behind the front face plate. The only thing I can check is that the wall chase still feels cold to the touch when it's running (the backside of the chase is in the garage so I can feel it and it's still cold).

If you can't see the vents because the insert surround covers them those vents are obstructed.

 

[riles246]

If you can't see the vents because the insert surround covers them those vents are obstructed.

You can't see any of the old fireplace- the insert and surround covers entirely the old fireplace. But isn't that how all inserts work? The decorative trim ensures that you can't see any of the old. The vents inside the old one were not visible before the insert either unless you stuck your head inside and looked up; that's why I think they may still be open as the insert doesn't project up into the cavity where the vents were located. Anyway, I'm not a fireplace pro, I just don't know- I relied on the pros who installed it when they said it was safe.

Regarding the other poster, the house is 2600 sq. ft. and built in the 70's. I wasn't expecting to heat the entire house though, just to offset the heating costs for the room and possibly some of the first floor. Said another way, I didn't expect my heating bills to drop to zero, just to reduce by some percentage (and not to increase!).

Thanks both!

 

[bholler]

You can't see any of the old fireplace- the insert and surround covers entirely the old fireplace. But isn't that how all inserts work? The decorative trim ensures that you can't see any of the old. The vents inside the old one were not visible before the insert either unless you stuck your head inside and looked up; that's why I think they may still be open as the insert doesn't project up into the cavity where the vents were located. Anyway, I'm not a fireplace pro, I just don't know- I relied on the pros who installed it when they said it was safe.

Regarding the other poster, the house is 2600 sq. ft. and built in the 70's. I wasn't expecting to heat the entire house though, just to offset the heating costs for the room and possibly some of the first floor. Said another way, I didn't expect my heating bills to drop to zero, just to reduce by some percentage (and not to increase!).

Thanks both!

Do you have a before pic? Or know the model of the fireplace?

 

[riles246]

Do you have a before pic? Or know the model of the fireplace?

It's an MD36.

 

[bholler]

MAJESTIC M28 INSTALLATION MANUAL Pdf Download

View and Download Majestic M28 installation manual online. M Series. M28 indoor fireplace pdf manual download. Also for: M36, Md36, M42, Md42, M28-ao, M36-a0, Md36-a0, Md36r-a0, Md36l-a0, Md42-a0.

www.manualslib.com

Installation precautions on page 3 are pretty clear that you can't install any components or accessories not specified by majestic

 

[BrianVA]

I am not a huge fan of #1 (cracked window), as long as the fireplace is not struggling to burn or back drafting, etc, i don't think this is necessary, and isn't going to help (someone could correct me as I may be wrong here).

^^This. There is no way opening a window is going to make your house warmer.

 

[BrianVA]

As others stated, once you establish a good burn, turn the combustion air down in increments over the course of 30 - 45 min's until you achieve a "lazy flame". This is a good way to burn with a noncat stove or insert. If you leave the combustion air on high, the heat is mostly going up the flue.

Also try experimenting with different speeds on the blower. I usually run mine on low or medium, rarely high. Unscientifically, it seems like I get better heat when I don't run the blower wide open. My theory is that it cools the unit so much that the heat output actually suffers. Like I said, very unscientific, you should do your own trial and error.

Lastly, try experimenting with different configurations for your cold air and hot air fans. I mount an 8" fan in the top of the door frame pointing out of the fireplace room to move the hot air. I only run that fan on low. To mount it, I just use an F clamp on the door frame (so I can easily take it down when we have guests, my wife doesn't like it). I don't use a cold air fan. I know many will point out that its easier to move cold air than hot air, which is true, but I've done a lot of trial and error and know what works best for my setup. My theory is the combustion air naturally works to pull cold air into the room. Once again, I have no science to back this up.

 

[riles246]

^^This. There is no way opening a window is going to make your house warmer.

I'll give it a try for another couple weeks and find out! So far the only difference when running this way has been that the room with the fireplace only gets to 71F or 72F, instead of 73F+, but my theory is that it isn't sucking any cold air through other rooms which have their own thermostats and heating zones to try to compensate.

The room with the fireplace has a thermostat set to 68F for its heating system so as long as the temp is above that, I'm at least not running heat to heat up any new air besides what the fireplace is doing. At this point if I can just make the fireplace not hurt the bills, even if not helping the bills, I'd be somewhat happy.

I like the idea of perhaps installing a duct in the ceiling to the other story to spread it around better too, might pursue that as a spring/summer project in prep for next winter.

 

[riles246]

Plus all of the air being pulled through the zero clearance box and chimney to cool it.

I think this is my issue- the firebox is SO cold when the fire isn't running, and the lower chimney exit (the vent air) looks like it's dumping tons of heat out of the house when the fire is running. When the fire isn't running, there is a very cold breeze coming from the fireplace; on close inspection, the breeze is not coming from the flue, it's coming from the vents. I also hate getting a draft started- smoke dumps into the house for 1-5 minutes until the draft switches, then it still comes in through the vents (up the flue and then down the vents) until the flue heats up enough to switch the draft on the vent.

Looks like my summer project will be to replace the firebox. I went the insert route in hopes that it would help me avoid major construction, but I'm going to call it a failed experiment. Now I'm back in planning mode, and there appear to be three options: 1. get a new zero clearance firebox that uses outside air for combustion and venting, and put my existing insert in it. 2. get a new zero clearance fireplace that is efficient in its own right and just sell the insert. 3. give up on wood and get the most efficient gas fireplace I can find (and get a propane tank and gas line to feed it). Or I guess 4- ditch it all and just put something decorative in the space where the fireplace currently sits, and fully insulate the chase. I'm already $6k into the problem and it looks like that is going to prove to be a total loss, so #4 doesn't sound so crazy, sadly.

The primary issue that even started me down this path is how cold the room with the fireplace gets when there is no fire. That issue still exists; the only thing the insert helped with was allowing for a long, controlled fire which makes the issue go away for basically an entire day until it all cools down again.