Ventless or Vented gas logs?

[Michael Larson]

Originally Posted by jjonas

I have it easy in Minnesota, as ventless are banned. If no vent to the exterior, it gets written up!

It's odd that Minnesota does not outlaw kerosene heaters. I guess they will get to it later.

Well as Souchery says-" Minnesota, the state where nothing is allowed"


BTW- According to the CPSC, there are no deaths associated with the use of vent free fireplaces that are equipped with and ODS

http://www.ventfree.org/images/stori...es/cpscltr.pdf

[David A. Andersen]

Problem #1: The burning of natural gas produces large quantities of water (1.5 gallons for every 100,00 BTU's of gas burned.)

Where the hell did the mold come from?

Problem #2: discharging combustion gases directly into the living space of the house is only theoretically "safe"!

The assumption is that the appliance is utilized in a poorly constructed building that exceeds the minimum building airflow standard (ASHRAE 62 -- 89). Any attempts at weatherization by a professional or the homeowner may result in unsafe carbon monoxide levels in the house.

To start with, there is insufficient building envelope leakage to let the carbon monoxide out, insufficient leakage to allow dilution air into the living space and insufficient leakage for adequate makeup/combustion air resulting in elevated carbon monoxide as a result of incomplete combustion. But then we all rely on that oxygen sensor the appliance has (heaven knows this thing will never fail)!

Weatherization programs pending ratification by the House of Representatives prohibit unintended combustion appliances with the exception of gas ranges and ovens. These appliances will be tested during the process and appropriate ventilation will be required in accordance with test results.

Install them now and you'll have to uninstall them later. No weatherization work can be performed (not one caulked window) on a house without removing unvented fireplaces without assuming 100% liability for future performance of this appliance and the maintenance of adequate ventilation.

As Joe looks for "just the facts", take a carbon monoxide test after you exceed the standards of practice by lighting fires in the fireplace!

[Michael Larson]

As Joe looks for "just the facts", take a carbon monoxide test after you exceed the standards of practice by lighting fires in the fireplace!

I have measured CO and guess what?

1-2 PPM or better.

[James H. Bushart]

Originally Posted by jfunderburk

Do you have any data to substantiate that claim? Let me go ahead and answer for you. NO.

Here's a some more objective information.

Interesting.

You modify my statement by removing half of what I said, and then challenge me to "substantiate" your modification.

I didn't realize this was one of those moronic "NFE" threads. Sorry.

Even the manufacturers of these inaccurately named "ventless" gas appliances will warn the consumer to keep a window open while operating.....like someone in February who needs the extra heat is actually going to open a window when they turn on their "ventless" device. LOL

As for the number of folks who have died as a result of carbon monoxide poisoning in in homes that they have had tightened....or did themselves.....without knowing to add mechanical air to keep their gas appliances from backdrafting......there are many. Google them, yourself.

Home inspectors should be warning their clients about these devices and particularly should be educating them to understand that they are not "ventless". They will vent whatever they do not combust.....and (especially when connected to LP) will pump in pints of moisture by the hour.

[Michael Larson]

Home inspectors should be warning their clients about these devices and particularly should be educating them to understand that they are not "ventless". They will vent whatever they do not combust.....and (especially when connected to LP) will pump in pints of moisture by the hour.

Do you warn you clients about the use of their "ventless" gas range and ovens?


I doubt it.

[James H. Bushart]

Originally Posted by mlarson

Do you warn you clients about the use of their "ventless" gas range and ovens?


I doubt it.

I absolutely do.

If you have one, put the probe of a combustion analyzer into the exhaust of the oven when it is on maximum burn. The undiluted exhaust will be at or near 30 ppm. A gas oven with any rust or uneven burn can be even higher. Put a skillet on an open burner flame....and watch it get yellow and orange....and put your probe a foot above it....and you'll get about 4-6 ppm. Now, turn on the indoor vent and let this stuff blow in your face.

Even with a clean burn and a low level of CO, the steam from the boiling pots simply blows back into the house.

In every case....especially in the modern, energy efficient tight house....gas appliances should be vented to the outside and failure to recommend that is an error on the part of the inspector, IMO.

There are a lot of folks who sit at the dinner table with a sudden headache that they can't explain....and when it goes away, they forget about it.

Codes are minimum basic standards and, while I have none in my area at all, even in civilized parts of America....some will require venting of a gas stove to the outside.

It's the right thing to do and that should be what we recommend. In the absence of a vent, a window should be opened when the gas appliance is operating.

[Michael Larson]

I always recommend venting ranges to the exterior but have never encountered high CO readings as you describe from a properly adjusted gas appliance.

[Bob Elliott]

I warn people about the Carbon Monoxide dangers of ventless exactly as Mike recommended.

I use the stover and oven example.

Every winter deaths are attributed to "poor families" using the stove as a heat source.

[Wayne B. Wilson]

Originally Posted by mlarson

I have measured CO and guess what?

1-2 PPM or better.

I have seen go up to 10 to 12 Micheal.

[Michael Larson]

Originally Posted by wwilson3

I have seen go up to 10 to 12 Micheal.

And the allowed limit is what?