Ventless Fireplace Efficiency: What 99% Really Means
The 99.9% efficiency claim on ventless fireplaces is true and nearly useless. What it measures, what it excludes, and why it cancels itself out.
indoor air quality
CO Alarm and a Ventless Fireplace: A Condition of Use
Not a tip, not an accessory. Why a working carbon monoxide alarm is a condition of operating a vent-free gas appliance, and what to do when one sounds.
Ventless Fireplace Nitrogen Dioxide and Asthma
Carbon monoxide is not the only combustion byproduct in the room. What NO2 is, why it matters for asthma, and why a CO alarm does not see it.
Oxygen Depletion Sensor: What an ODS Does Not Catch
An ODS is a low-oxygen gas shutoff, not a carbon monoxide detector. The exact code language, the 18 percent figure, and where the protection stops.
Ventless Fireplace Oxygen Depletion: The Mechanism
A vent-free burner draws its oxygen from the room you are sitting in. What that actually does, why the code caps input by room volume, and what it does not tell you.
Ventless Fireplace Carbon Monoxide: The Mechanism
Vent-free means the exhaust stays in the room. When carbon monoxide forms, why the ODS does not catch it, and why the alarm is not optional.
Are Ventless Gas Fireplaces Safe? An Honest Answer
A neutral answer with nothing to sell: what a vent-free burner puts in your room, what the ODS does and does not do, and where it is never allowed.