How Much Heat Do Pine Pellets Give, and How Long Does a Bag Burn?

"How many calories do pine pellets give?" and "How long does a bag of pellets last?" are asked together. Neither has a single-number answer: the calories depend on the class and moisture of the pellets, and the burn time on the output and efficiency of your stove. This article gives the reliable lower limit first, then shows how to work out a bag's burn time for your own appliance. The times below are not promises but examples with stated assumptions.

How many calories do pine pellets give?

In all its classes, A1 included, ENplus requires a net calorific value of at least 16.5 MJ/kg as received. That is at least 4.6 kWh/kg, or about 3,950 kcal/kg (1 kWh = 860 kcal). Pine pellets in a bag with the ENplus A1 seal cannot be below that limit.

Three points to note:

• It is a lower limit. Certified pellets may be somewhat above it; we do not publish a calorie figure of our own. Using the lower limit keeps the calculation cautious.
• What does "as received" mean? It means the moisture in the pellets (at most 10% under ENplus) is taken into account. Be wary of a very high calorie figure on a bag marked "dry basis": the ENplus rules forbid stating a dry-basis calorific value on the bag, because ignoring moisture makes the figure look higher than it is.
• What difference does pine make? Softwoods such as pine contain more lignin and resin, so in dry wood their heating value is slightly higher than that of hardwoods; sources put the difference at about 5%, which is also how much samples vary. So it is not right to say that pine pellets have far more calories. See pine pellets or oak and beech pellets? for the detail.

How much energy is in a bag?

Using the lower limit:

• A 15 kg bag: 15 × 4.6 = 69 kWh of fuel energy.
• A 20 kg bag: 20 × 4.6 = 92 kWh of fuel energy.

Not all of that energy reaches the room; part of it goes up the flue. The share that reaches the room is the appliance's efficiency.

Efficiency belongs to the stove, not the fuel

The efficiency is on your stove's label and in its manual; use that figure in the calculation. Two official reference points for orientation: the US Environmental Protection Agency (EPA) says certified pellet stoves usually fall in the 70–83% efficiency range, and the European Union's Ecodesign rule has required a seasonal efficiency of at least 79% for pellet stoves since 2022. The examples below assume between 70% and 85%.

How long does a bag burn? The method

Hourly pellet consumption is found with this formula:

Consumption (kg/hour) = the stove's heat output (kW) ÷ (4.6 kWh/kg × efficiency)

Time (hours) = bag weight (kg) ÷ consumption (kg/hour)

Pellet stoves do not run at full output all the time; they turn down as the room warms. So do the calculation for the output level your stove actually runs at. Three examples:

• Low setting, 3 kW: consumption about 0.77 – 0.93 kg/hour. A 15 kg bag lasts about 16 – 20 hours, a 20 kg bag about 21 – 26 hours.
• Medium setting, 6 kW: consumption about 1.5 – 1.9 kg/hour. A 15 kg bag lasts about 8 – 10 hours, a 20 kg bag about 11 – 13 hours.
• High setting, 9 kW: consumption about 2.3 – 2.8 kg/hour. A 15 kg bag lasts about 5.5 – 6.5 hours, a 20 kg bag about 7 – 9 hours.

Assumptions: net calorific value 4.6 kWh/kg (the ENplus lower limit), efficiency 70% – 85%, the stove running continuously at the stated output. The short end of each range corresponds to 70% efficiency and the long end to 85%.

Why the result depends on your appliance

• Output level: the same bag lasts about three times as long on the low setting as on the high one. The insulation of the house and the temperature outside decide how long the stove runs at each level.
• Efficiency: an uncleaned burn pot, a blocked flue or the wrong air setting lowers it.
• The state of the pellets: damp or dusty pellets give less heat per kilogram.
• Running pattern: a stove that cycles on a thermostat uses fewer pellets per hour on average.

Your stove's manual usually gives the hourly pellet consumption (kg/hour) at the lowest and highest settings; that figure gives the most accurate time: simply divide the bag weight by it.

How many bags for a winter?

A season's needs follow the same logic: divide your seasonal heat demand (kWh) by 4.6 × efficiency. We explain the method step by step in how many pellets you need for a winter; for a rough estimate use the fuel calculator.

The pellets we sell are 6 mm pellets made from 100% pine sawdust, with the ENplus A1 logo on the bag; we sell them in 15 kg and 20 kg bags and deliver orders of 1,200 kg or more as bags on pallets. For product details see our pine wood pellets page; for pellet classes and delivery areas see wood pellets in İzmir. We do not publish the price on the site; ask for the current pine pellet price on WhatsApp. We explain what sets the price in what determines the price of pine pellets.

Sources: net calorific value limit from ENplus ST 1001:2022, Annex A, Table 4; ban on dry-basis calorific values on the bag from ENplus ST 1003:2022; pellet stove efficiency from US EPA Burn Wise, "Pellet Stoves" and Commission Regulation (EU) 2015/1185, Annex II; heating value of softwoods and hardwoods from A. J. Baker (USDA Forest Products Laboratory), 1983.