Comments on: Is an Unvented Gas Fireplace More Efficient Than a Condensing Furnace?

By: Sherri Fox

Sherri Fox — Wed, 18 Dec 2019 20:12:23 +0000

In reply to Tom Phillips. I appreciate this information
I appreciate this information. I live in a very small house . At the moment I have a huge beast of a heater in my front room that heats the whole house. But I wanted to install gas wall heaters in three rooms and get rid of the huge beast. This gave me the information I needed to chose the right product.

By: John Proctor

John Proctor — Wed, 13 Nov 2019 02:14:08 +0000

@Anne The vented heater is
@Anne The vented heater is better because it is designed to capture all the combustion products -- something a fireplace sometimes doesn't do. In addition the fireplace "sucks" a lot of the room air and sends it up the chimney which is replaced in the house with cold outside air. However putting in gas logs along with opening the chimney is better than what you have now.

By: Anne

Anne — Tue, 12 Nov 2019 10:55:20 +0000

In reply to John Proctor. Thanks, and I see! Is the
Thanks, and I see! Is the vented heater that different than adding venting back to the fireplace and putting in vented logs? We do have gas and we do have dual HVAC electric.

By: John Proctor

John Proctor — Mon, 11 Nov 2019 15:59:34 +0000

@Anne You are right not more
@Anne You are right not more of the same. Primo: The new item should be vented to outside. If you are worried about your electric bill in the winter I am interpreting that you have a heat pump. If you have natural gas at your house and are willing to heat only one primary area then a gas space heater (vented to the outside) might be the best option. If on the other hand you have propane, you might look at a mini-split heat pump with a delivery head in that one primary area. If you go with the mini-split don't believe the efficiency they claim, but heating one area with a variable compressor speed heat pump that HAS A REAL THERMOSTAT ON THE WALL AND DOES NOT RUN THE FAN THE WHOLE TIME should make it possible to reduce the use of your whole house ducted heat pump.

By: Anne

Anne — Sun, 10 Nov 2019 00:32:28 +0000

Thank you! I’ve read your
Thank you! I’ve read your blog before and ended up back here reading up on ventless gas logs. We bought a 1915 brick home this summer (in southwestern Virginia) and it has unvented gas logs inside a sealed fireplace (just above the firebox, with a thick sheet of metal). The inspector said the logs are old and should be replaced, but I’m not sure what to replace them with….? A vented gas fireplace? A wood burning insert? A pellet stove? I know your answer is “not more of the same.” What to do with an existing setup, though?

We currently have gas service for the stove and hot water heater as well as the logs, and would likely need a new panel box to accommodate coming off gas entirely, when you factor in the car charger we are installing soon. We are on a budget and like the idea of some heating source to supplement and back up the 13-SEER older dual hvac units we have. The previous owner used the gas logs a lot and still had high electric bills. In general, IAQ and carbon footprint are our major concerns.

Thanks for any advice you might have!

By: Peter Newton

Peter Newton — Thu, 18 Apr 2019 13:48:27 +0000

Happy to be reading this even
Happy to be reading this even though the timing is just over a year behind its posting. Ended up here after Googling AFUE for unvented space heaters. Building analyst here researching, reading and filling my quiver. Super pleased to see some progress in gaining ground in the annals of Mr. Bailes. Quite happy to walk alongside from here as a faithful friend and someone who finds harmony in your speak.

By: John Proctor

John Proctor — Sat, 21 Apr 2018 22:26:29 +0000

Whether one calls it a
Whether one calls it a decorative gas log, or a heater, there is nothing that keeps people from running them for long periods. I do not argue that unvented gas ovens are good, or that gas cook tops are good for the indoor air quality and our health. Gas ovens used to be vented by the way. My indoor air quality monitor detects when we use the electric oven and when we use the gas cooktop with the power venting always on. For years people have been testing ovens and cooktops for CO and know that there are numerous incidents of problem emissions. These same people have not had the equipment to measure NO2. If they did, we would see the real life teeter-totter between NO2 and CO.
One of the buried items from the NCAT Critical Needs Weatherization Research Project was:
“In a 1987 Pennsylvania study of low income weatherization, N02 concentrations were measured in the fall (prior to air sealing) and mid-winter (after air sealing). There were three homes in Pittsburgh that had electric ranges. These three homes averaged 0.013 ppm N02 in both the fall and mid-winter. On the other hand, the 12 homes in Pittsburgh equipped with gas ranges had an average N02 concentration of 0.046 ppm prior to air sealing and 0.071 ppm after air sealing. A number of these units exceeded the 0.08 ppm World Health Organization for 8 hour exposure. The average measured mid-winter N02 concentrations in the Philadelphia gas range homes was 0.09 ppm (above the WHO standard)”. (GRI1987)

By: David Butler

David Butler — Fri, 20 Apr 2018 23:46:42 +0000

In reply to Donald Love. @Donald, gas ranges are
@Donald, gas ranges are required to have vent fans. Big difference. Whether or not they get used is on the occupant.

By: RoyC

RoyC — Fri, 20 Apr 2018 20:50:09 +0000

In reply to Donald Love. Yea, if it is a decorative
Yea, if it is a decorative gas log, it may be used only occasionally, but some of these have pretty high capacity. My bigger concern is the use of unvented gas heaters which are only used for heating, not ambiance. I still wouldn't have either in my house.

By: Donald Love

Donald Love — Fri, 20 Apr 2018 20:26:20 +0000

Brilliant post! I never
Brilliant post! I never really thought that the energy from condensing the water would remain in the conditioned area.

Regarding the “we need to ban these” bandwagon, I think a step back should be taken. Gas logs are primarily used for occasional ambiance, not a primary heating source. I have one, and I can say with great certainty that I’ve done more unvented burning of natural gas via my stove/oven than I have with the ventless gas log. If you’re worried about poor people misusing heat sources, then you should focus on gas/propane ovens. Growing up in poor, rural Michigan, I can tell you that’s the “go-to” hillbilly temporary furnace.