How this calculator works
First work out how much heat the house needs over the winter: the heated area times the annual heat per square foot for your climate, adjusted for insulation and the share you want from the stove. Then work out how much useful heat a ton of pellets gives: a ton holds about 16.4 million BTU (8,200 BTU per pound), and the stove delivers its efficiency's share. Divide one by the other.
Worked example: a 1,500 ft² house in a moderate climate (30 kBTU per ft²) with average insulation needs 45 million BTU a year. A stove at 80% turns a ton of typical pellets (16.4 million BTU) into 13.12 million BTU of heat, so you need 45 ÷ 13.12 = 3.4 tons, which is 172 bags of 40 lb. At $7 a bag that is $1,204, or about 1.1 bags on an average day of a 150-day season.
Tons of pellets for 100% pellet heat (80% stove, typical pellets, average insulation)
Halve the numbers if pellets supply half your heat. Multiply by 50 for 40 lb bags.
| Area heated | Mild | Moderate | Cold | Very cold |
|---|---|---|---|---|
| 1,000 ft² | 1.1 | 2.3 | 3.4 | 4.6 |
| 1,500 ft² | 1.7 | 3.4 | 5.1 | 6.9 |
| 2,000 ft² | 2.3 | 4.6 | 6.9 | 9.1 |
| 2,500 ft² | 2.9 | 5.7 | 8.6 | 11.4 |
Tips before you buy
- Buy in spring or summer when pellets are cheapest, and not in the first cold snap, when stores run short and prices rise.
- Keep pellets dry. Wet pellets swell, crumble and jam the auger. Store them indoors or in a dry shed, up on a pallet.
- Look for pellets with low ash (under 1%), such as premium hardwood grades, and keep to the grade your stove's manual recommends.
- Clean the burn pot and the ash pan as often as the manual says. A stove that is dirty loses efficiency, and burns more pellets for the same heat.
- Pellets are heavy: a ton is 50 bags of 40 lb. Plan the lifting, the storage space and whether the supplier will deliver and stack.
Tools & materials for this project
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Frequently asked questions
How many bags of pellets do I need for a winter?
Usually 2 to 5 tons (100 to 250 bags of 40 lb) when the stove is the main heat for an average home. A supplemental stove in a tight house may need 1 to 2 tons.
How many pellets does a pellet stove burn per day?
Typically 1 to 3 bags (40 to 120 lb) a day in cold weather and under a bag a day in mild weather, though it depends on the heat setting and how well the house is insulated.
How many bags of pellets are in a ton?
50 bags of 40 lb, which is 2,000 lb. Check the weight printed on the bag, because other bag sizes exist.
Are pellets cheaper than firewood?
Usually not. At $350 a ton for pellets and $300 a cord for firewood, pellets cost about $26.68 per million BTU of heat against about $17.86 for wood, which is about 50% more. Pellets are cleaner and feed automatically. Use the heating cost comparison calculator with your own prices.
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Related calculators & guides
Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.