**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 custom build 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, t he 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 Inventor ies and does not inc lude 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 ofte n for over 8 months per year, e.g. , mid
-September through mid
- May. A lso, s ome hydronic heaters are even used 12 mo n ths per year i n order to heat water for do mestic use i n the residence and for outdoor pools and hot tubs. 3. Since you provided more nuanced em ission 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 sta t ed above and in Section 4.2 of the RIA, our emission factors are based on the RWC emission estimation tool . W e 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 potentiall y regulate at various emission levels. W e are not aware of any state regulation or any voluntary program that distinguishes between freestanding wood stoves and wood stove that are fireplace inserts. Distinguish ing between catalytic stoves a n d noncatalytic stoves has been do ne in the 1988 NSPS and the 1995 Washington State emission levels. Today, however, as we d iscu ss in the preamble, the states and EPA prefer to not subdivide catalytic and noncatalytic stoves but rather let manufacturers choose for themse lves 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 ge neral intent of section 111 and EPA’s long standing goal of do i ng 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 estim ates for catalytic, noncatalytic, hybrid, or innovative systems. FYI: Anecdotal CBI oral info suggests that hybrid systems may actually be che a p er and perform better for some appl i cations, 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 differen t 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 oral ly 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 an d approved fo r EPA a nd OMB use for multiple future rules . Plus, th is woodstoves rule is not likely to be major example for the new employment impacts language anyway.