Response to 11-20-13 email from Cortney Higgins with questions and comment s on RIA

Email Questions: 

1. What is EPA doing about allowing manufacturers to sell products that have been already 

produced? There doesn’t seem to be language in the RIA, please point us to the right spot in the 

preamble if it’s discussed there.

A: This is discussed for each subpart in the RIA on pages 2-2, 2-3, 2-11, and 2-18. Note that sale 

is not distinguished on page 2-18 because most masonry heater manufacturers actually custombuild the heaters on the buyer’s site. 

2. We didn’t see any clarification on the usage rate. Can you clarify if that these heaters are used 

24 hours/day over how many months?

A: As stated in Section 4.2 on page 4-1 of the RIA, the emission estimates are based on the total 

tons of wood burned, not heater hourly usage rates. The RIA also notes that we used the 

Residential Wood Combustion (RWC) emission estimation tool. This tool is informed by data for 

the National Emission Inventories and does not include national heater hourly usage rates. Also, 

state surveys typically do not include heater usage rates. The few state surveys and local 

information that address usage rates typically show that many of the heaters are often used 24 

hours per day and often for over 8 months per year, e.g., mid-September through mid-May. 

Also, some hydronic heaters are even used 12 months per year in order to heat water for 

domestic use in the residence and for outdoor pools and hot tubs.

3. Since you provided more nuanced emission factors for different classes of heaters, why didn’t 

you carry through the analysis to emission reduction estimates? This would aid presenting the 

analysis provision-by-provision.

A: As stated above and in Section 4.2 of the RIA, our emission factors are based on the RWC 

emission estimation tool. We showed that tool’s nuanced breakdown so that readers could 

potentially re-trace our calculations if they wanted to do so. The nuanced breakdown does not 

help inform our analyses that are geared towards the subcategories [shown in the RIA and in 

Table 1 of the preamble] to potentially regulate at various emission levels. We are not aware of 

any state regulation or any voluntary program that distinguishes between freestanding wood 

stoves and wood stove that are fireplace inserts. Distinguishing between catalytic stoves and

noncatalytic stoves has been done in the 1988 NSPS and the 1995 Washington State emission 

levels. Today, however, as we discuss in the preamble, the states and EPA prefer to not 

subdivide catalytic and noncatalytic stoves but rather let manufacturers choose for themselves 

how to best meet the emission limits for their specific models. No one knows what the future 

percentages of catalytic, noncatalytic, hybrid, or innovative systems will be. Specifying the 

emission levels and not the technology is consistent with the general intent of section 111 and 

EPA’s long standing goal of doing so as far as practical. Considering that over 90 % of today’s 

new wood stoves are noncatalytic, we are comfortable with our best estimate analyses that do 

not assume different R&D cost estimates for catalytic, noncatalytic, hybrid, or innovative 

systems. FYI: Anecdotal CBI oral info suggests that hybrid systems may actually be cheaper and 

perform better for some applications, but again no one knows the percentages for the future 

yet.
Comment bubbles in RIA redline/strikeout:

A1. “Is this useful life?”

Yes. We will add “useful life of” prior to “40 years or more” on page 1-3.

A2: “Do 2022 shipments grow further at the same rates or stay same? This point should be clarified.”

Yes, this is discussed in the paragraph on page 4-11 immediately preceding the subject Table 4-4 

on page 4-12.

A3: “Did EPA correct the mis-identification of tables between the proposal and the alternative?”

Yes.

A4: “If EPA is able to identify different emission factors for different heaters, why not carry through to 

results? Same comment on other tables as well.”

See answer to Question 3 above.

A5: “Flag for future discussion, depending on the status of the revised language.”

Yes, as discussed orally earlier, OMB and EPA should plan to discuss potential language on how 

EPA should describe analyses of employment impacts in the context of a future EPA rule since 

new language is not ripe in time for this rule and may take awhile to be fully polished and 

approved for EPA and OMB use for multiple future rules. Plus, this woodstoves rule is not likely 

to be major example for the new employment impacts language anyway.