Very lost on gas insert efficiency, please help

[GratefulBear]

Greetings forum,
I've been doing a lot of reading here lately but first time posting. When I started pondering getting a gas insert, I didn't think efficiency would be an issue. Gas furnaces can be so efficient. However, I was shocked to find the efficiency with an insert can go as low as in the 50's. Moreover, it is very difficult to find guidance on getting an efficient insert. Some of the manufacturer's make that info hard to find, I can't find any website that compares efficiency of the various brands, and I've spoken with two stores who had trouble getting me that information and one said they rarely get asked that question... We have an ideal setup to be able to heat our whole 2,300 sf open floor plan house with an insert as the fireplace/chimney is central to the house and by the areas we spend the most time in and like to keep the warmest. I also can't see pulling the trigger on something that has worse efficiency than our 40 year old oil furnace (80%). The best I could find was a Napoleon Roxbury 30 that is only 24000 btu but is 85% efficient, but has been discontinued We need something that is 38k plus with a good turn down ratio, but most importantly efficient. Can any of you fine folks help me out in my quest?

 

[begreen]

First and foremost, it's going to depend on what fits in the fireplace, check dimensions. The Pacific Energy Tofino i40S insert boasts 78% efficiency and the Enviro EX35 touts 75%. I don't have a full listing, but for some other examples, the Quadrafire Excursion III is about 72% efficient and the QFI35FB around 75%, I recall the Jotuls being in the ~65% efficiency range with good turn down, Valor inserts average around 70%, same with Regency's E33.

 

[GratefulBear]

The Pacific Energy is getting warmer (no pun intended). Thank you. Attached are the measurements. The back starts to taper gradually around 14" up. I'm not opposed to using a spacer trim kit if needed for depth.

 

[begreen]

Note that efficiency may vary with the output setting. For example, Lopi lists their 616 gas insert at 85% efficient, at high output. The P4 Canadian efficiency rating is about 73% on LP. Most of the efficiency listings above are to the Canadian rating standard.

That is a good-sized fireplace. It should handle most inserts.

 

[GratefulBear]

Ah. That's a huge piece of information (that they may be using different standards for measurement). Good to know, thank you. The industry really makes it clear as mud. I like that Mendota appears to be more open about the efficiency and how it's measured. FV44i at 82% with P4 but not sure if it fits yet. Is there anywhere that lists all the different brands/models and efficiency? I tried searching for a Canadian govt site but no luck

 

[Lennox65]

Greetings forum,
I've been doing a lot of reading here lately but first time posting. When I started pondering getting a gas insert, I didn't think efficiency would be an issue. Gas furnaces can be so efficient. However, I was shocked to find the efficiency with an insert can go as low as in the 50's. Moreover, it is very difficult to find guidance on getting an efficient insert. Some of the manufacturer's make that info hard to find, I can't find any website that compares efficiency of the various brands, and I've spoken with two stores who had trouble getting me that information and one said they rarely get asked that question... We have an ideal setup to be able to heat our whole 2,300 sf open floor plan house with an insert as the fireplace/chimney is central to the house and by the areas we spend the most time in and like to keep the warmest. I also can't see pulling the trigger on something that has worse efficiency than our 40 year old oil furnace (80%). The best I could find was a Napoleon Roxbury 30 that is only 24000 btu but is 85% efficient, but has been discontinued We need something that is 38k plus with a good turn down ratio, but most importantly efficient. Can any of you fine folks help me out in my quest?

Gas inserts aren't designed to evenly heat a 2300 sq foot area. They are labeled as "supplemental heat sources, and not intended to be the main heat source". The efficiency rating would be a moot point as you would be overheating the area closest to the insert to barely raise the temp a few degrees at the other side of the open concept room.

 

[GratefulBear]

Gas inserts aren't designed to evenly heat a 2300 sq foot area. They are labeled as "supplemental heat sources, and not intended to be the main heat source". The efficiency rating would be a moot point as you would be overheating the area closest to the insert to barely raise the temp a few degrees at the other side of the open concept room.

I know they're not really designed for even heating and that's something we like about it actually. The fireplace is central to the living area (kitchen, living room, dining room) and we normally keep the thermostat off on the second floor as too much heat rises up there anyways due to the open layout. I don't understand why efficiency would be a moot point, as you put it. If you are overheating an area then either the btu's are too high or the turndown ratio isn't large enough. I'd rather pay less money per btu of heat output (and less carbon emissions). If efficiency is a moot point, then why not just buy cheap inserts that get 25% efficiency? Just seems like the industry is behind the ball and I bet part of that is gas inserts are typically bought by people who are well off and not as concerned with economics. It looks like the industry in the UK has caught on and they have (new) more efficient options there.

 

[ABMax24]

Here's is the Natural Resources Canada list on fireplace efficiency: https://oee.nrcan.gc.ca/pml-lmp/index.cfm?action=app.search-recherche&appliance=FIREPLACE_G

One thing to note is fireplaces with a standing pilot light often have a much lower efficiency because it is assumed the heat from the pilot light does not enter the room and is wasted, with my gas fireplace this isn't the case as the glass stays quite hot with just the pilot light on and some of that heat enters the room. That being said my gas fireplace is rated at something like 55% efficiency, its auto ignition counterpart is about 70%, which is still a substantial amount of heat vented directly outside.

There are ways to may a gas fireplace more efficient, but issues then appear with condensation in the flue piping, which really limits the efficiency to about 80%. Granted this list does have more than a few models at 80%.

 

[bholler]

I know they're not really designed for even heating and that's something we like about it actually. The fireplace is central to the living area (kitchen, living room, dining room) and we normally keep the thermostat off on the second floor as too much heat rises up there anyways due to the open layout. I don't understand why efficiency would be a moot point, as you put it. If you are overheating an area then either the btu's are too high or the turndown ratio isn't large enough. I'd rather pay less money per btu of heat output (and less carbon emissions). If efficiency is a moot point, then why not just buy cheap inserts that get 25% efficiency? Just seems like the industry is behind the ball and I bet part of that is gas inserts are typically bought by people who are well off and not as concerned with economics. It looks like the industry in the UK has caught on and they have (new) more efficient options there.

Gas fireplace inserts or fireplaces are not going to come anywhere near as efficent as a furnace. They are designed to have an attractive fire which absolutely is not efficient. Their fire is tuned to have a nice looking orange flame to imitate a wood fire. That isn't efficient. They have a large firebox with a relatively small heat exchanger unlike a high efficiency furnace which is mostly heat exchanger.

And you assumption that you can heat the whole house without over heating the space it's in as long as it's sized property just is not accurate. Your home requires a certain amount of BTUs to maintain temperature. With a space heater all of those BTUs have to come from one spot. That is going to lead to high temps near the heat source no way around it.

All that being said getting the most efficient insert available is certainly a good thing. But if your goal is to.reduce consumption and emissions as much as possible a properly zoned high efficiency furnace is the answer

 

[Lennox65]

I know they're not really designed for even heating and that's something we like about it actually. The fireplace is central to the living area (kitchen, living room, dining room) and we normally keep the thermostat off on the second floor as too much heat rises up there anyways due to the open layout. I don't understand why efficiency would be a moot point, as you put it. If you are overheating an area then either the btu's are too high or the turndown ratio isn't large enough. I'd rather pay less money per btu of heat output (and less carbon emissions). If efficiency is a moot point, then why not just buy cheap inserts that get 25% efficiency? Just seems like the industry is behind the ball and I bet part of that is gas inserts are typically bought by people who are well off and not as concerned with economics. It looks like the industry in the UK has caught on and they have (new) more efficient options there.

The technology has evolved greatly to increase efficiency. Open faced B vent gas fireplaces sucked heated room air up the flue. Direct vent fireplaces changed that but the early standing pilot units were still only marginally efficient. Some newer direct vent fireplaces have the ability to draw some of the heat from the fireplace and duct it into another room. The efficiency rating system is confusing and I have not wasted any time trying to figure it out. My customers are typically only concerned with a good looking flame.

 

[GratefulBear]

Here's is the Natural Resources Canada list on fireplace efficiency: https://oee.nrcan.gc.ca/pml-lmp/index.cfm?action=app.search-recherche&appliance=FIREPLACE_G

One thing to note is fireplaces with a standing pilot light often have a much lower efficiency because it is assumed the heat from the pilot light does not enter the room and is wasted, with my gas fireplace this isn't the case as the glass stays quite hot with just the pilot light on and some of that heat enters the room. That being said my gas fireplace is rated at something like 55% efficiency, its auto ignition counterpart is about 70%, which is still a substantial amount of heat vented directly outside.

There are ways to may a gas fireplace more efficient, but issues then appear with condensation in the flue piping, which really limits the efficiency to about 80%. Granted this list does have more than a few models at 80%.

Thank you so much. I've used that site a lot in the past 12 hours. I'm partway through the process of getting quotes on a couple models and I'll update on here later

 

[John Ackerly]

Here's is the Natural Resources Canada list on fireplace efficiency: https://oee.nrcan.gc.ca/pml-lmp/index.cfm?action=app.search-recherche&appliance=FIREPLACE_G

One thing to note is fireplaces with a standing pilot light often have a much lower efficiency because it is assumed the heat from the pilot light does not enter the room and is wasted, with my gas fireplace this isn't the case as the glass stays quite hot with just the pilot light on and some of that heat enters the room. That being said my gas fireplace is rated at something like 55% efficiency, its auto ignition counterpart is about 70%, which is still a substantial amount of heat vented directly outside.

There are ways to may a gas fireplace more efficient, but issues then appear with condensation in the flue piping, which really limits the efficiency to about 80%. Granted this list does have more than a few models at 80%.

Thanks ABMax. Do you know who measures the efficiency? Is it a third party lab? If I recall, the DOE wanted to regulate the efficiency of gas fireplaces, but HPBA wanted them to be a "decorative" appliance? Is that part of the reason efficiency info is so hard to find?
John

 

[ABMax24]

Thanks ABMax. Do you know who measures the efficiency? Is it a third party lab? If I recall, the DOE wanted to regulate the efficiency of gas fireplaces, but HPBA wanted them to be a "decorative" appliance? Is that part of the reason efficiency info is so hard to find?
John

My understanding is the testing is performed by a certified third party lab, and the testing is done as per CSA P.4.1-15.

I can't speak to the US, but in Canada they are broke into 2 groups; gas fireplace heaters, and decorative gas fireplaces. The latter must be marked as decorative as it's primary function is not for heating. Heaters must meet a minimum of 50% efficiency, a decorative fireplace has no such requirement. Both are quite frankly absurd in todays day and age, IMO 75% should be the minimum, a new gas furnace install in Canada must exceed 95%.

Here is some more reading on the topic:

Gas fireplaces

May 2017 Technical bulletin on amending the standards

www.nrcan.gc.ca

Gas fireplaces

Energy Efficiency Regulations Regulatory definition Gas fireplace, a decorative gas fireplace or a heating gas fireplace.

www.nrcan.gc.ca

 

[John Ackerly]

My understanding is the testing is performed by a certified third party lab, and the testing is done as per CSA P.4.1-15.

I can't speak to the US, but in Canada they are broke into 2 groups; gas fireplace heaters, and decorative gas fireplaces. The latter must be marked as decorative as it's primary function is not for heating. Heaters must meet a minimum of 50% efficiency, a decorative fireplace has no such requirement. Both are quite frankly absurd in todays day and age, IMO 75% should be the minimum, a new gas furnace install in Canada must exceed 95%.

Here is some more reading on the topic:

Gas fireplaces

May 2017 Technical bulletin on amending the standards

www.nrcan.gc.ca

Gas fireplaces

Energy Efficiency Regulations Regulatory definition Gas fireplace, a decorative gas fireplace or a heating gas fireplace.

www.nrcan.gc.ca

Thanks for the info on Canada. I never imagined it would be so hard to answer these questions about gas stoves in the US! Maybe if I start a new thread with a good heading, some gas manufacturers may reply. I agree, 50% is ridiculous. Its really not that hard to get a vented gas appliance to be pretty efficient and would save a lot of money for consumers. These days, who wants to use a lot more gas than we need to?

 

[Fingerlakes Fireplace]

Thanks for the info on Canada. I never imagined it would be so hard to answer these questions about gas stoves in the US! Maybe if I start a new thread with a good heading, some gas manufacturers may reply. I agree, 50% is ridiculous. Its really not that hard to get a vented gas appliance to be pretty efficient and would save a lot of money for consumers. These days, who wants to use a lot more gas than we need to?

It is impossible to get above 85 percent efficiency.
Unless you go condensing, and power vent. Which is a whole new can of worms. You will also lose all ability to run it off a batteries in a power outage.
I think most furnace manufacturers only reach 83% efficiency before they switch to condensing.
There are many other factors I would consider, before trying to get the last 5% of efficiency.
A while ago, I calculated what it would cost a person to run a 30,000 BTU fireplace on natural gas. It was somewhere around .30 to $0.35 an hour on high. An increase in 5% efficiency would save you how much??

 

[ABMax24]

Thanks for the info on Canada. I never imagined it would be so hard to answer these questions about gas stoves in the US! Maybe if I start a new thread with a good heading, some gas manufacturers may reply. I agree, 50% is ridiculous. Its really not that hard to get a vented gas appliance to be pretty efficient and would save a lot of money for consumers. These days, who wants to use a lot more gas than we need to?

I'm not sure why there is such a lack of interest in efficiency from US regulatory bodies.

I look at the $700 50k BTU unit heater I have in my garage, it is 80% efficient (bare minimum for Canada) and is extremely simple in design. Yeah it's noisy and not what I'd want in my house, but the possibilities are there.

Honestly though I don't know many people that use their gas fireplaces very often, every house in my neighborhood has one, but its an uncommon site to see steam coming from the exhausts, hard to justify using it for space heating when we all have 95% efficient condensing furnaces.