10/27/2012

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Hydronic Heater NSPSIndustry Perspective

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Presented by the 

Hearth, Patio & Barbecue Association

Hydronic Heater Terminology

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• Outdoor Furnaces/Outdoor Wood Furnaces (OWF)

• Outdoor Wood Boilers (OWB) 

• Outdoor Wood Hydronic Heaters (OWHH)

• Wood Hydronic Heaters (WHH) includes Indoor 

Hydronic Heaters

Hydronic Heaters

• Hydronic Heaters are appliances that burn wood or pellets and 

produce hot water. 

• They can be pressurized but are most North American Hydronic 

Heaters are unpressurized. 

• Warm air furnaces are a totally different product category.

• They produce heated air not heated water.
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Hydronic Heaters - Background

Timeline

• 2004

– ASTM test method development begins.

• Essential first step – can’t have emission limits without a test 

method.

• 2006

– EPA, NESCAUM, NESCAUM States and HPBA Outdoor 

Hydronic Heater Caucus hold stakeholder meetings for 

NESCAUM Model Rule and EPA Voluntary Program.

• 2007

– January: EPA Voluntary Program for OWHH is launched. 

• Phase 1 PM limits of 0.60 lb/mmBtu Input.

• Phase 2 PM limits of 0.32 lb/mmBtu Output (90% PM Control).

– NESCAUM Model Rule has EPA Phase 2 limit.

• EPA test method (EPA M28 OWHH) based on very early ASTM 

draft.

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• 2008

– July: ASTM Hydronic Heater Test Method (ASTM 

E2618) Published.

• 2010

– March: EPA Voluntary Program Phase 1 Ends.

• 2011

– April: EPA commences stakeholder process to modify 

EPA M28 OWHH to address output and efficiency 

determination issues.

– October: EPA M28 WHH adopted. 

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Summary

• Tremendous progress has been made in a very short period.

– 12 models qualified under EPA Voluntary Program Phase 1.

• Average PM – 0.84 lb/mmBtu Output

• 26 cordwood models qualified under Voluntary Program 

Phase 2.

– 13 Manufacturers in the program.

• Stakeholders recognized that the “fast start” for the program 

implicated unforeseen problems and agreed to cooperatively 

work and in good faith to resolve them.

– EPA M28 OWHH test method issues were resolved in this 

manner.

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• The EPA Hydronic Heater Voluntary Program should been 

seen by all as a huge success.

– Problems that have been encountered have been 

cooperatively resolved.

– The significance of those problems has been 

disproportionally emphasized by some stakeholders.

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Co-Proposal (0.15 lb/mmBtu Output) for 

Hydronic Heaters

• EPA cannot support a finding that 0.15 lb/mmBtu

Output is achievable by “demonstrated” technology.

– Only two cycling models have been qualified below this 

level under the Voluntary Program, using EPA Method 28 

WHH.

• One of these is at 0.14 lb/mmBTU –barely under the limit.

• Two other models have been qualified below this level using EPA 

Method 28 OWHH making these data suspect for BDT 

consideration.

– Test Method Precision needs to be taken into account in 

standard-setting.

• No rigorous precision analysis is yet possible for M28 WHH.

– Precision is likely to be similar to the precision for the Wood Stove test 

methods.

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• “European Technology” employing “Partial Thermal Storage” 

won’t support the co-proposal.

– The emissions data for PTS appliances are from the EN test method, 

which doesn’t provide a “reasonable worst case” emission profile. 

– This creates an “apples and oranges” problem: 

• The EN data cannot be adjusted to M28 WHH equivalents.

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• The test method differences (EN303-5 v. EPA M28WHH or ASTM E2618) make 

comparison of corresponding test results impossible.

– An ASTM test method that specifically addresses PTS appliances is still 

under development. 

• Good progress is being made by the ASTM task group which includes participation 

by representatives from EPA, Brook Haven National Laboratories (NYSERDA 

Contractor) and Vermont and is being monitored by a number of other interested 

parties.

1North American and European Wood-Fired Boiler Testing Comparison, Rick Curkeet, PE, Chief Engineer –

Hearth Products, Intertek Testing Services, Inc., September 28, 2010

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ASTM PTS Test Method

• Key Elements of the Draft Test Procedure include:

– “Cold” starts from empty fireboxes for the two lowest heat output 

categories (Categories 1 & 2).

– “Hot” starts on coal beds for the medium and maximum heat output 

test runs (Categories 3 & 4).

– The option for a partial fuel load in the Category 1 (Lowest Heat 

Output) test run to prevent an appliance-forced shutdown that would 

otherwise void the test run. 

– A procedure for determining that combustion has completely ceased 

before the full test fuel load is consumed.

– Inclusion of the manufacturer’s recommended minimum storage 

volume as part of the test apparatus.

– A requirement that the Category 2 test run consume the full test fuel 

load.

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• Limited data indicates that crib fuel is very 

problematic for PTS appliances.

• Available test data (all with cordwood) 

generated during PTS test method 

development are indicating that heaters that 

employ PTS could have weighted average PM 

emissions (lb/mmBtu Output) in the same 

range as Phase 2 cycling models.

– The cold starts for the low heat output categories 

are contributing significantly to total PM.

• The low heat output categories are heavily weighted in 

the average emission ratings.

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• In consequence, setting the standard at 0.15 

lb/mmBtu Output can be expected to 

disqualify many PTS models when they are 

tested with the new PTS test method.

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Cost Effectiveness

• We have very serious doubts that the coproposal is cost effective, since 0.32 lb/mmBtu

Output already represents 90% particulate 

emission control. 

– Industry is developing a rigorous cost effectiveness 

analysis.

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• EPA must stick with 0.32 lb/mmBtu output.

– 90% particulate emissions reduction is a remarkable level 

of improvement for batch-fired, consumer-operated 

combustion devices.

– EPA has qualified 26 cordwood-fired models to this limit 

under the Voluntary Program. 

– HH manufacturers have accomplished this in record time 

and at considerable cost. BUT:

» These models are produced by only 13 manufacturers – less than 

half of the total North American HH manufacturers.

» Many additional models need to be developed and qualified to 

meet marketplace demands.

• The 26 models are only a fraction of all models produced by 

the 13 Voluntary Program manufacturers. 

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Conclusions Regarding the Co-Proposal

• 0.32 lb/mmBtu is NOT a “low bar.”

– While 26 models have been qualified, an unknown 

but significant number were sent to the lab with 

confidence they would pass, and actually failed.

– The precision of EPA Method 28 WHH has not 

been determined.

• Due to the random nature of burning wood, it is 

unlikely to be better than the precision of the 

woodstove test methods.

• Lowering standards without taking the precision of the 

compliance methods into account is inappropriate and 

arbitrary. 

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EPA’s Proposal to Add an Efficiency 

Standard for Hydronic Heaters

• There are major problems with the proposed 

efficiency standards: 

– EPA has discredited the efficiency data database. 

– The precision of the efficiency determination has not been 

determined. 

• The format of the standard (lb/mmBtu Output) 

already indirectly regulates efficiency by making 

manufacturers accountable for heat output.

• Instead of efficiency standards, we support the 

previous EPA position: a requirement to report 

efficiency values for consumer use. 

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