EPA Wood Stove Rules: The 2020 Emission Limits
New wood stoves must emit no more than 2 grams of particulate matter per hour, or 2.5 g/h if certified using the cord-wood test. Those are the Step 2 limits in 40 CFR 60.532, in force since May 15, 2020. The earlier Step 1 limit, from May 15, 2015, was 4.5 g/h.
The limits
| Step | From | Limit |
|---|---|---|
| Step 1 | May 15, 2015 | 4.5 g/h |
| Step 2 | May 15, 2020 | 2 g/h |
| Step 2, cord-wood test option | May 15, 2020 | 2.5 g/h |
The rule applies to heaters manufactured, imported or sold at retail. It is a weighted average across burn rates measured in a lab, so a stove fed wet wood or turned down to smoulder at home will do worse.
Where listed stoves fall
Every stove on this site publishes an emission rate below the Step 2 limits. The cleanest is the Woodstock Absolute Steel Hybrid 211 at 0.5 g/h, and the highest is the Osburn 2000 at 2.3 g/h. Each stove page shows its rate as a share of the limit.
Some makers also print efficiency on two bases. The higher heating value (HHV) counts the energy needed to evaporate the water formed when wood burns; the lower heating value (LHV) does not, so LHV figures read higher. Drolet's HT-3000, for example, publishes 71% HHV and 76% LHV. Cord Calc uses HHV where a maker gives it.
What it means when you buy
- Ask for the certified rate in g/h and check which test it was certified on (crib wood against 2, cord wood against 2.5).
- Size it to the house. A stove too big for the space spends its life turned down, which is where emissions and creosote climb. Start with the stove size chart.
- Burn dry wood. The certified rate assumes it; see how to season firewood.
State and local air agencies can add their own rules, such as burn bans on bad-air days; check yours.
Sources
- 40 CFR 60.532, Standards for particulate matter.
- Maker product pages for each stove, linked from its page.
Questions
What is the EPA limit for wood stoves?
Under 40 CFR 60.532, wood heaters made or sold from May 15, 2020 must meet a weighted average of 2.0 grams of particulate per hour, or 2.5 g/h if certified with the cord-wood test method. The 2015 Step 1 limit was 4.5 g/h.
Can I still use an old wood stove?
The federal limits apply to heaters manufactured, imported or sold at retail; check with your state and local air agency for any rules on existing stoves.