What are Burn Times?
A burn time is the total amount of time a single load of wood will burn from ignition through to smoldering. This includes from the time you light a stove, to when the coals are hot enough that you can add another log and the fire ignites again (without having to use another match). Burn time does not refer to the amount of time a piece of wood will display visible flames and be producing large amounts of heat (BTUs).
How Burn Times Work
There is a lot of confusion around the concept of burn times for wood burning fireplaces, stoves, and inserts. While the idea seems straightforward, in reality, it is anything but. A burn time refers to the maximum amount of time a wood unit will burn from a single load of wood. This seems simple right? Put a log in and measure how long it burns, therefore that is the burn time. Unfortunately, it is not that straightforward and there are a number of factors that affect burn times, the most influential being the fireplace settings – burning on high vs burning on low.
When looking at a fireplace you will likely see two key elements – BTUs (heat output) and burn time (total duration). Typically, consumers think the stated BTUs of a unit are the number of BTUs that the unit will always produce, when in fact it is the maximum output. The same goes for burn times, it is the maximum a fireplace can burn for under ideal conditions, not the average duration.
These numbers are highly related and depending on how a unit is burned a consumer can maximize the BTUs, maximize burn time, or end up somewhere in the middle, but they can never have both. Typically, BTUs are listed at their maximum or High Heat Value (HHV) and burn times are listed at their maximum or Low Heating Value (LHV).
For example:
- A fireplace burning at on high (HHV) will produce 55,000 BTUs and burn for a duration of 2.5 hours.
- The same fireplace burning on low (LHV) will produce 18,000 BTUs and burn for a duration of 8 hours.
Therefore, the units
listed max BTU will be
55,000 and the
listed burn time will be
8 hours. The fireplace is capable of doing one or the other, however will not be able to do them at same time. HHV fires result in quick and hot burns that rapidly use fuel and LHV fires result in slow, stable, less intense burns that lengthen the fuel consumption.
Watch: Our Regency F2450 Non-Catalytic Wood Stove burn for 10 hours
Factors Affecting Burn Times
Many different factors affect the burn time of a wood burning stove, fireplace, or insert. Aside from the design and model of the fireplace, the following are the most influential factors for burn times:
Type of Wood
Different wood types will yield longer, hotter burns, while some will yield cooler and shorter burns. Typically, hardwoods like oak, walnut, and cherry burn longer than softwoods such as pine and fir.
Moisture Content
Wood with high moisture content will have less lengthy burns and very high moisture content can cause damage to the fireplace, stove, or insert. The lower the moisture content the longer burn times you will receive. Make sure to always burn only
properly seasoned wood to avoid damage to the unit. There should be a moisture content of below 20% in wood used for burning.
Burn Settings
An air damper setting that is wide open (no restriction) will cause the fireplace, stove, or insert to burn very hot and short as the fire is able to consume as much oxygen as it wants, therefore using all the available fuel quicker. For longer burns, restrict the airflow to the fire to draw out the length of the fuel burning. Low airflow fires will burn at a lower BTU output for long periods whereas high airflow fires will spike with a quick rush of BTUs and quickly burn out, requiring additional wood.
Installation
The installation of a wood stove, fireplace, or fireplace insert can dramatically affect the burn times. If the venting travels too far or the unit is incorrectly installed there will be a decrease in performance. To ensure your Regency wood unit is properly installed always contact a
certified Regency fireplace retailer or installer.
Climate Conditions
The altitude and humidity also affect the burn times of fireplaces. Higher altitudes decrease the burn times of most fireplaces as there is less available oxygen and the efficiency is decreased. High humidity also decreases burn times. The moisture in the air decreases the fire’s efficiency and lowers the expected burn times.
How to get your fireplace to burn as long as possible
The following is the best practices to ensure a long, warm fire for as long as possible:
- Use only well-seasoned wood
- Burn hardwood
- Fully load the firebox
- Set air damper to ‘low airflow’ setting
- Sit back, relax, and enjoy hours of warmth!
Longest Burning Wood Stoves, Insert, & Fireplaces
Typically catalytic or hybrid wood stoves produce the longest burn times. Catalytic stoves and inserts produce long-term stable heat outputs due to their design and the nature of a catalytic combustor.
(Check out the Regency Cascades series of Hybrid Wood Stoves & Inserts featuring Eco-Boost technology that boasts an impressive 12+ hours of burn time!)
Frequently Asked Questions
How to make wood burn slower in a fireplace?
Slowing down the burn comes down to controlling the fuel and oxygen:
- Fuel: Use seasoned hardwood with a moisture content of 15–20% for a slower burn, overly seasoned wood with a very low moisture content may burn faster
- Oxygen: Adjust the air control or damper to reduce the oxygen supply. Less oxygen slows combustion. Check your door seals to ensure a proper fit.
Installing a high-efficiency wood stove with precise air control settings, like those offered by Regency, also improves burn time and heat output.
What is the longest burning species of firewood?
The longest burning firewoods are dense hardwoods:
- Hickory: Burns the longest and produces the most heat (27–30 million BTUs/cord).
- Oak: Provides a consistent, slow burn with high heat output (24–29 million BTUs/cord).
- Black Locust: Burns long and hot with low smoke (25–27 million BTUs/cord).
- Beech & Ironwood: Also known for their slow burn and consistent heat.
Softwoods like pine or fir burn quickly and are better suited for starting fires rather than sustaining them.
Why is my wood stove burning wood so fast?
Several factors can cause fast-burning wood:
- Air Leaks: Check the gasket seal on the door for gaps; leaks can pull in excess air.
- Overloaded Firebox: Burning too many small logs at once can increase airflow between pieces.
- Wood Quality: Ensure you're using seasoned hardwood with the right moisture content (around 15-20%).
Balancing airflow and wood type will also help improve burn control and heat efficiency.
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