Will my fireplace put out the same heat after it's converted from natural gas to propane?
Yes — a properly converted fireplace puts out essentially the same rated heat on propane as it did on natural gas. The conversion kit swaps the orifices and resets the pressure so the burner delivers the same BTU output. Propane carries more energy per cubic foot, so you burn less volume for the same warmth — but the heat in the room is the same.
Same BTUs, different fuel math
A fireplace is rated in BTUs, and that rating is what you feel. When we convert a unit to propane, we install the propane orifices and set the manifold pressure the manufacturer specifies for LP — that's how a Napoleon Ascent or a Kozy Heat Springfield hits the same output number on either fuel. What changes is the plumbing behind it: propane packs roughly two and a half times the energy of natural gas per cubic foot and runs at higher pressure, so the propane orifices are physically smaller. Same heat, less gas volume, different-size holes.
When output actually shifts
A handful of units carry a slightly different BTU rating on propane versus natural gas — the spec sheet spells it out, and the gap is usually small. The bigger real-world variable is elevation. Up in the higher WNC coves and cabins, thinner air means less oxygen, and some appliances need a high-altitude adjustment so the flame burns clean and complete instead of lazy and sooty. Propane is fussier about this than natural gas. We check the spec plate and your elevation before we quote, so the flame you get is the flame the maker intended.
The part that must be right
Heat output only stays honest if the conversion is done correctly — wrong pressure or the wrong orifice gives you a weak flame, sooty logs, or a burner that short-cycles. This is licensed gas work in North Carolina for exactly that reason. We convert to the printed pressure, test the flame, pressure-test the line, and update the rating plate. Call (828) 545-0525 and we'll tell you your unit's propane numbers before we touch anything.
Related questions
- What happens if you run a natural gas fireplace on propane without converting it?
- Do natural gas and propane flames look different in a fireplace?
- What parts get changed when a fireplace is converted from one gas to the other?
- Can I convert my natural gas fireplace to propane?
- What is an orifice in a gas fireplace and why does it matter which fuel I use?
- How do I know if my house has natural gas or propane?
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