Gas vs Wood Fireplace Heat Output: Which is Superior?

//Gas vs Wood Fireplace Heat Output: Which is Superior?

When it comes to deciding whether to install a new gas or wood fireplace in your home, there are many factors to consider. Cost, safety, ambiance, and convenience are all among them. But if you’re primarily looking for a way to heat your home, heat output is probably you’re top priority. We often get asked if a gas or wood fireplace is superior in this regard. The answer: It depends.

Gas vs Wood Fireplace Heat Output

The first thing to understand in regards to heat output is how it is measured – in BTU’s (short for British Thermal Units). The textbook definition of a BTU is, “the quantity of heat required to raise the temperature of one pound of water one degree Fahrenheit at a specified temperature”. For our purposes, just think of one BTU as roughly equivalent to the amount of heat one lit match generates.

The number of BTUs a gas or wood fireplace can generate varies widely, depending on the size and model of the fireplace. Generally speaking, gas fireplaces can produce anywhere from 8,000-60,000 BTUs, and wood burning fireplaces range from 20,000-40,000 BTUs. Therefore, either type of fireplace can do the job in most cases.

It’s also critical to keep the wider issue of energy efficiency in mind, as in the amount of energy that is lost during the production of heat:

Wood Fireplace Efficiency

gas vs wood fireplace heat output

Traditional wood fireplaces are notoriously inefficient, converting only 15-30% of the wood’s energy into actual heat. For instance, if a traditional wood fireplace generates 20,000 BTUs, it’s only turning 3,000-6,000 BTUs (20,000 * 15-30%) into actual heat.

Luckily, there are now High-Efficiency Wood Fireplaces that carry a much higher efficiency rating (75%+), lending themselves to much better heat production. The key difference from traditional wood fireplaces is that the firebox is separated from the interior of the home by a sheet of heat-resistant glass, rather than being in open air. The heat is funneled through a separate vent above the glass and sends the smoke directly up through the chimney.

Gas Fireplace Efficiency

gas vs wood fireplace heat output

Gas fireplaces have excellent efficiency (77%+). Like high-efficiency wood fireplaces, the firebox of a gas fireplace is separated from the interior of the home by heat-resistant glass. There are two different kinds of gas fireplaces: Direct Vent and Vent Free.

Direct vent fireplaces use two-way vents to supply outside air for combustion. Because of this, they are not quite as efficient as vent free fireplaces. Vent-free fireplaces rely on indoor air for combustion and don’t send exhaust outside (therefore not needing a chimney or flue). This makes them the most efficient from a heat output perspective.

How Many BTUs Do I Need For My Fireplace?

To know how many BTUs you’ll need, you’ll need to determine how many square feet you’re looking to keep warm, consider the climate you live in, and keep in mind how well your home is insulated. This BTU calculator provided by can help give you a general idea of how many BTUs you should be looking for from your fireplace.

2018-07-16T16:16:17-04:00 November 1st, 2017|Blog|Comments Off on Gas vs Wood Fireplace Heat Output: Which is Superior?