Wood Stove and Fireplace Emissions Calculator
What this calculator reports
Result: emitted particulate mass, not indoor PM2.5 concentration or exposure. EPA AP-42 presets represent PM-10 or total particulate under the cited methods. Actual smoke varies widely with appliance condition, fuel, moisture, draft, loading, and operation.
Burning details
Estimated result
Calculation steps
- Fires per year
- 3 × 20 = 60
- Dry wood per fire
- 10 kg × (1 − 20%) = 8 kg
- Annual dry wood
- 8 kg × 60 = 480 kg
- Particles emitted
- 480 kg × 17.3 g/kg = 8,304 g/year
Screening estimate only. It does not calculate chimney concentration, indoor exposure, carbon monoxide risk, or net climate impact.
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How to Use the Calculator
- Use a tested rate when possible. Find the exact model's particulate g/h value on its label, manufacturer report, or EPA database, then enter burn hours and frequency.
- Use a fuel factor for screening. If there is no model-specific rate, select the closest AP-42 device category and enter as-burned wood per fire.
- Enter moisture on a wet basis. For example, 10 kg of wood at 20% moisture contains an estimated 8 kg dry wood.
- Check the method and scope. Review the factor, substituted steps, and limits before copying or downloading the estimate.
Formulas and Assumptions
With a model-specific tested rate:
Annual particles (g) = emission rate (g/h) × hours/fire × fires/week × weeks/yearWith a fuel-based factor:
Dry wood (kg) = as-burned wood (kg) × [1 − moisture (%) ÷ 100]Annual particles (g) = dry wood/fire × fires/week × weeks/year × emission factor (g/kg dry wood)Moisture is assumed to be reported on a wet basis. The adjustment changes the dry-wood mass used in the AP-42 equation; it does not model the additional real-world smoke caused by poor combustion, wet fuel, smoldering, start-up, or reloading.
Health, fire, and carbon-monoxide limit: This estimate cannot show whether a room, chimney, or outdoor area is safe. Keep working smoke and CO alarms, follow the appliance manual and local burn restrictions, burn only permitted fuel, and use qualified chimney or hearth professionals for inspection and installation. If a CO alarm sounds or anyone has symptoms, leave the area and follow emergency guidance.
Included Fuel-Based Particulate Factors
These inventory factors are converted from EPA AP-42 pounds per ton to numerically equivalent grams per kilogram by multiplying by 0.5. They are category averages, not current certification claims.
| AP-42 device category | Factor | Original basis | Important note |
|---|---|---|---|
| Open fireplace | 17.3 g/kg | 34.6 lb/ton dry wood | PM-10, filterable + condensable; rating B |
| Conventional stove | 15.3 g/kg | 30.6 lb/ton | Uncertified conventional category; rating B |
| Noncatalytic Phase II stove | 7.3 g/kg | 14.6 lb/ton | 1990-era EPA category; rating B |
| Catalytic Phase II stove | 8.1 g/kg | 16.2 lb/ton | 1990-era EPA category; rating B |
| Certified pellet stove | 2.1 g/kg | 4.2 lb/ton | Certified under the 1988 NSPS category; rating B |
| Masonry heater | 2.8 g/kg | 5.6 lb/ton | AP-42 exempt device category; rating B |
How to Interpret the Result
The result is an estimated mass leaving the combustion source over the selected period. It is not an ambient or indoor concentration in µg/m³, an Air Quality Index value, a dose, or a prediction of health effects. Converting emitted mass to concentration would require a dispersion or indoor-air model with stack, weather, building, and ventilation data.
This calculator also does not report CO₂, CO, VOCs, black carbon, or air toxics. Wood smoke contains multiple pollutants, and EPA identifies fine particles as its largest health threat. Biogenic CO₂ accounting is deliberately excluded because gross combustion emissions and net climate impact are different questions.
Methodology Review and Primary Sources
Methodology review: Starlight Tools checked the equations, unit conversion, preset factors, default result, and edge limits against the sources below on August 3, 2026. No EPA affiliation or external professional certification is claimed.
- U.S. EPA AP-42 Section 1.10 — Residential Wood Stoves: device-category particulate factors, units, field-test basis, and limitations.
- U.S. EPA AP-42 Section 1.9 — Residential Fireplaces: 17.3 g/kg dry-wood PM-10 factor and rating.
- U.S. EPA — Certified Wood Stoves: current U.S. particulate limits and test-fuel distinction.
- U.S. EPA — Smoke from Residential Wood Burning: wood-smoke composition and health context.
Frequently Asked Questions
How do I estimate wood stove particulate emissions?
Use a tested rate for the exact model when available: multiply g/h by annual operating hours. Otherwise, multiply dry wood burned by a documented g/kg factor. Category factors are less specific.
Where can I find the appliance emissions rate?
Check the permanent certification label, manufacturer test report, or EPA Certified Wood Heater Database. Record both the rate and whether the model was tested with cord wood, crib wood, or pellets.
Does this estimate PM2.5?
No. The AP-42 presets represent PM-10 or total particulate under cited test methods, and certified labels report particulate mass. Do not relabel the output as measured PM2.5.
Why does moisture matter?
AP-42 factors are per mass of dry wood. The calculator removes the entered wet-basis water fraction to estimate dry mass. It does not separately predict how wet wood changes combustion quality.
Are AP-42 factors certification limits?
No. They are inventory averages and are not standards or performance guarantees. Several stove categories use older certification-era names; use the appliance-rate method for a current exact-model value.
Can this predict indoor air quality or CO risk?
No. Emitted mass is not concentration or exposure, and carbon monoxide is not calculated. Use working alarms and follow appliance, venting, chimney, and local safety requirements.
Is wood burning carbon neutral?
Not automatically. Burning releases CO₂. Net accounting depends on sourcing, regrowth, time, land use, and the chosen framework. This tool intentionally reports particulate matter only.
Are my inputs uploaded?
No. Calculation, copy, and CSV export happen locally in your browser. The page does not transmit your values.