Ms. Brenda Edwards U.S. Department of Energy Building Technologies Program, MS EE-2J EERE-2011-BT-TP-0042 1000 Independence Avenue, S.W. Washington, D.C. 20585-0121 Re: NOPR to Revise Water Heater Test Procedures Docket No. EERE 2011 BT-TP 0042 Dear Ms. Edwards, The Air-Conditioning, Heating, and Refrigeration Institute (AHRI) is the trade association representing manufacturers of air conditioning, space heating, water heating and commercial refrigeration equipment. AHRI s 315 member companies include all the major manufacturers of residential and commercial water heaters doing business in the U.S. We submit the following comments on the Notice of Proposed Rulemaking issued in the November 4, 2013 Federal Register. This notice proposes revised efficiency test procedures for residential water heaters and certain commercial water heaters in response to the directive in the American Energy Manufacturing Technical Corrections Act (AEMTCA) to develop a uniform efficiency descriptor and corresponding test procedure for residential and commercial water heaters. Our comments include comments on the issues listed in the NOPR and other issues that are of concern to us. Issues Noted in NOPR 1. Is the proposed definition of light commercial water heater appropriate, and is it appropriate to test commercial water heaters meeting this definition under the uniform descriptor, while testing all other commercial water heaters using thermal efficiency and standby loss? The proposed definition is incomplete and imprecise, thus including models that should not be in this subcategory of commercial water heaters. The second criterion used to define models considered to be light commercial is inappropriate since most water heaters, under a unique confluence of conditions in the field, may inadvertently deliver water at a temperature of 180F. This condition will not occur with every water heater; it may occur very rarely; and it may involve only a small amount of heated water. Most importantly, the delivery of water at 180F in this case is the result of field conditions and usage. It is not the normal or intended operation of the unit. The key factor that is missing in the proposed definition is that the water heater is designed to deliver water at a thermostatically controlled temperature of 180F or higher. The delivery of water at that temperature is by design and controlled. Water is delivered at that temperature as a normal operating mode of the model; it is not the happenstance of a singular set of unusual conditions coming together in the field. DOE should modify this criterion as
Page 2 of 9 shown below and as we recommended in our February 11, 2013 comments submitted in response to the Request for Information for this rulemaking. Is not designed to deliver water at a thermostatically controlled temperature of 180F or more The third criterion in the definition is appropriate but not universal for the U.S. market. There are many jurisdictions which require commercial water heaters to bear a stamp signifying compliance with the ASME Boiler and Pressure Vessel Code. There are also many jurisdictions which do not require commercial water heaters to bear an ASME stamp. As proposed all these latter models, regardless of storage volume or input rate, would be defined as light commercial. There are models of gas and oil commercial water heaters that have very large storage tanks or input rates in the hundreds of thousands of Btu/h or both and that do not have 180F thermostatic controls and are not ASME stamped. These models unquestionably are not intended for residential use and must not be included in the definition of light commercial water heater. We again refer to our February 11, 2013 comments which include limits on input rating and storage volume to more precisely define the water heater models that would be tested using the universal efficiency descriptor test procedure. We recommend that DOE include the following parameters as part of the criterion defining light commercial water heater. Gas-fired Storage Oil-fired Storage Electric Storage (Includes Tabletop models) Heat Pump with Storage Gas-fired Instantaneous Electric Instantaneous Oil-fired Instantaneous Rated input: 100,000 Btu/hour or less; Rated storage volume: 100 gallons or less. Rated input: 140,000 Btu/hour or less (nominal 1 gph oil flow); Rated storage volume: 50 gallons or less. Rated input: 12kW or less; Rated storage volume: 120 gallons or less. Current rating: 24 amperes or less, Voltage rating: 250 volts or less Rated storage volume: 120 gallons or less. Rated input: less than 200,000 Btu/hour; Water volume: less than 1 gallon per 4000 Btu/h of input. Rated input: 25 kw or less; Water volume: less than 2 gallons. Rated input: 210,000 Btu/hour or less (nominal 1.5 gph oil flow); Water volume: less than 2 gallons. Also, this subcategory should be renamed residential duty commercial water heaters. The designation of light duty commercial water heater has been used in the water heater industry for many years. As commonly understood in the field, this term has a meaning that is very different than that proposed in the NOPR for light commercial water heater. Although DOE s proposed term is not exactly the same as light duty it is close enough to cause unnecessary confusion in the field and impose an unnecessary burden on manufacturers who will have to respond to their customers confusion.
Page 3 of 9 We do not understand why the question in the second part of this issue is being raise. The situation being described is precisely what AEMTCA recognizes and allows. 2. Is information or data available regarding the translation of current first hour ratings to a first-hour rating determined using the proposed 125 F set point? What is the effect of such translation on the appropriate breakpoints between different size categories? Our water heater manufacturer members have conducted some comparative testing of first hour rating (FHR) as specified in the current test procedure and at the 125 F set point proposed in the NOPR. A summary of those test results is attached. Although the results are not all in the same direction, there is a clear and strong indication that the FHR test with a 125 F set point results in an appreciably lower FHR. Those tests at the 125 F set point which measured a lower FHR where on the order of 10 % lower than the current FHR rating test result. The ramifications of this are significant. First hour rating brackets are used to identify the simulated use test (SUT) that will be applied to measure the efficiency of a specific model. If these first hour rating brackets, and possibly the associated breakpoints, are not modified to correspond to this effect, many models that the manufacturers considered to be medium or high use models when the three proposed distinct SUTs were being developed, will be relocated to the next lower bracket and subjected to a SUT that will provide a lower energy factor (EF) for the model. Furthermore, any process to recalibrate the FHR brackets that determine the SUT to be used to measure the efficiency of a particular model will not be simple. The range and inconsistency of the comparative FHR tests conducted by DOE and our members indicate that a large testing effort will be required solely to determine accurately the effect of the 125 F set point on current FHR values. There is an additional, albeit not immediate, effect that must be considered. A key aspect of the current FTC EnergyGuide labels for residential water heaters is that models within a given range of first hour ratings are considered as having equivalent hot water delivery capability. This information is important in the selection of the proper water heater for a consumer s specific installation. If the FHR test is finalized as proposed, all of these ranges will have to be adjusted. Because the effect of the 125 F set point is not uniform, it will not be a simple case of models shifting to a different FHR range. The FHR is a relative measure of delivery capability. A FHR with a 125 F set point is different than the FHR determined by the current test but it does not in any way make the 125 F FHR a better or more useful metric. Recognizing this and considering the drastic effect of the 125 F set point on FHR values and the complexity it adds to the analysis for this rulemaking, we recommend that DOE not proceed with the changes to specify a 125 F set point for this test procedure. Rather, the test procedure should continue to use the 135 F specified set point. 3. Is the proposed method of characterizing water heaters as point-of-use, low, medium, or high appropriate and sufficient? Yes, we agree this method is appropriate and sufficient. 4. Are the draw patterns proposed for the different water heater size categories appropriate? Yes, although we prefer the patterns recommended in our March 18, 2013 comments. 5. What is the added burden, if any, in requiring a 24-hour pre-conditioning period for storage-type water heaters compared to current practice?
Page 4 of 9 There is a significant burden associated with the proposed 24-hour pre-conditioning period. As explained at the December 6, 2013 public meeting, AHRI has reconsidered this matter since the RFI phase of this rulemaking. We now recommend that a 24-hour pre-conditioning period be specified for storage water heaters but that period should not include the conduct of a SUT. The 24-hour pre-conditioning that has been used by the AHRI residential water heater efficiency certification program for many years and which is detailed in our testing guidelines is sufficient. 6. Is the proposed change to the nominal water delivery temperature to 125 F appropriate, and if not, what data or information is available that would justify a different water delivery temperature? The specification of a temperature set point is fundamentally a defined point of comparison. The specified temperature certainly should have some connection to field usage but in the case of residential water heaters there is no clear and distinct correct set point. Because of the concerns with the FHR discussed under Issue 2 and compelling logic to keep the temperature set point consistent throughout the test procedure, we recommend that the 135 F specification continue to be used in the test procedure. The recommendations made in our March 18, 2013 comments were based on the continued use of the 135 F set point. As we have noted previously, the continued use of this specification will likely reduce the complexity of the task of determining the conversion factor for translating current EF values to EF values representative of the universal efficiency descriptor (UED) test procedure. 7. Is the proposed method for setting the thermostat(s) of storage-type water heaters appropriate? We do not agree with the proposed method for setting the thermostat(s) on storage water heaters. The method used when the model has more than one thermostat should follow the basic principles of the procedure for setting thermostats in the current test method. 8. The addition of terms to quantify daily electric energy consumption separately from fossil fuel energy consumption and adding separate estimates of annual fossil fuel energy consumption and annual electrical energy consumption in addition to the overall annual energy consumption. We have no comment at this time. Other Issues The proposed addition of 429.17 to specify that the rated storage volume must be the average of the measured storage volume is unnecessary and is not an efficiency related matter. As such it is outside the scope of the DOE s authority. The current test procedure specifies first hour rating as the measure of a water heater s capacity. This has been the case since the DOE water heater efficiency test procedure was first developed. Storage volume is not the DOE specified metric for water heating capacity. It is very questionable whether enforcement regulations can be imposed on a metric that is not the model s efficiency or capability rating. As was discussed at the December 6, 2013 public hearing, the relationship of measured volume and rated volume is addressed by the applicable water heater safety standards. This has been the case going back many years before the DOE water heater efficiency test procedures were developed. The UL standard for residential electric water heaters requires that the measured volume be within -10% of the rated volume. The Z21 standard for residential type gas storage water heaters requires that the measured volume be
Page 5 of 9 within ±5% of the rated volume. The data from DOE s test, when properly considered in terms of the relationship of how the measured volume compares to the rated volume, reflects what is and has been the standard practice for residential storage water heaters. The measured volume is lower than the rated volume. If there were a real concern that this typical difference between the measured volume and the rated volume allowed manufacturers to dodge the minimum efficiency standards, that concerned would have evidenced itself already. That potential concern has existed since the first residential water heater standards were specified in NAECA in 1978. The test procedure proposed in this rulemaking does not change the situation at all. As DOE validated, the measured volumes of storage water heaters are consistently complying with the requirements of the nationally recognized safety standards. Manufacturers are not overstating the rated volume so that the minimum energy factor requirement for that model would be lower. The revised standards coming into effect in April, 2015 further diminish any potential for overstating the rated volume. The minimum EF for all electric storage water heaters will be 0.95 regardless of the rated storage volume. In the case of gas storage water heaters, the -5% tolerance of the gas safety standard precludes any nominal increase in rated volume to have a lower minimum EF applied to the model. A 40 gallon model, which likely has a measured volume between 38 and 39 gallons, could not simply be rerated to a 50 gallon water heater. It could not even be rerated to 42 gallons, which would drop the minimum by 0.01, because even a measured volume of 39 gallons would not comply with storage volume requirement of the safety standard. In view of the significant technology change required for models over 55 gallons by the April 2015 standard, there is no likelihood that manufacturers will claim rated volumes over 55 gallons that are inflated. On a practical basis, there also is no likelihood that manufacturers will simply lower the rated volume to avoid the standard applicable to models with rated volumes over 55 gallons. It must be recognized that this issue is independent of this rulemaking. It has been a theoretical possibility since the revised standards were finalized in 2010. However, the reality confirms that the concern is unwarranted. Attached are histograms based on the current directory for AHRI s residential water efficiency certification program. These histograms show the number of basic models of gas and electric storage water heaters listed in our program by volume size and energy factor and by volume size and FHR ranges. In the case of electric models there are 4 models that have a rated volume over 55 gallons and up to 60 gallons. Only 1 of these models has a rated volume above 55 gallons and that model s EF does not comply with the EF minimum of 0.95 specified by the 2010 final rule. That model could have a revised rated volume of 55 gallons but that change does not alter the non-complying status of the model relative to the revised standard going into effect in April 2015. The model will have to be redesigned to achieve a.95 EF. Thus, there is no advantage to make such a nominal change in the rated volume. In the case of gas water heaters, there are no models with a rated volume above 55 gallons that the manufacturer could rerate to 55 gallons or lower and still comply with the Z21 water heater safety standard requirement. The only rated volume for which this would be possible is 57 gallons. There are no such models in the market. Aside from the fact that the proposal to regulate the relationship of measured volume to rated volume in unwarranted; the specifics of the proposal are troublesome. As has been noted in previous water heater rule makings, and verified by DOE s own testing, the differences between the measured and rated volumes of gas and electric storage water heaters, on a practical basis, are fairly uniform. This is a long standing situation. Yet, the proposal would completely disrupt this practice by arbitrarily requiring that the rated volume be the average of multiple measurements of the measured volume. Such a change imposes significant burden on the manufacturers both in terms of additional testing and complete
Page 6 of 9 rewriting of their marketing literature for no corresponding improvement either in the DOE efficiency test procedure or the enforcement of minimum efficiency standards. Furthermore, it will not change the design or performance of the water heater in any way. The NOPR notes that the task to determine the conversion factor, which will be applied to current EF ratings to provide an EF reflecting the revised efficiency test procedure, will be undertaken after the UED test procedure if finalized. That process will have to include the translation of the April 2015 minimum standards and the minimum efficiency standards applicable to light commercial water heaters into EF minimums that reflect the UED test procedure. Even though this matter is a future activity, we are submitting these additional comments because of the significance of the conversion factor and the translated minimum efficiency standard. Manufacturers are implementing their plans for complying with the April 2015 standards. They are being required to address the effect of the revised efficiency test procedure at the same time. It is critically important that the conversion factor and translated minimum EF standards be determined through a thorough and timely analysis. We request that as soon as possible DOE provide a description of the process that will be used to determine the conversion factor and the schedule for completing this task. To minimize the testing burden and the difficulty of addressing the product development required to comply with the April 2015 standards while simultaneously responding to test procedure changes, the determination of the conversion factors must occur well in advance of the effective date of the revised efficiency test procedure. The determination of translated minimum efficiency standards to reflect the revised UED test procedure focuses primarily on the effect of the revised standard on models which are rated at the current minimum efficiency standard. In this case, this analysis is complicated by the fact that the single standard by fuel type will have to be translated to multiple standards; one for each usage pattern. Furthermore, the minimum thermal efficiency and maximum standby loss will have to be converted to one or two minimum EF requirements. The following table illustrated the minimum EF standards that will likely be required for various types of water heaters once the UED test procedure is finalized. Water Heater Type EF L EF M EF H EF POU Gas Storage 55G Gas Storage > 55G Gas Tankless (Res) Electric Storage 55G Electric Storage > 55G Electric Table Top Electric Tankless (Res) Oil Storage Gas Storage Light Duty (Com) Gas Instantaneous Light Duty (Com) Electric Storage Light Duty (Com) Oil Storage Light Duty (Com) Note: EF L, EF M, EF H, and EF POU represent the low, medium, high and point-of-use SUTs.
Page 7 of 9 The determination of the conversion factor as specified in AEMTCA, requires analysis beyond that described in the preceding paragraph. The purpose of the conversion factor is to allow a mathematical means to rerate every model covered by the UED test to an EF that reflects that test. This includes models currently defined as residential and models that will come under the subcategory of light commercial water heaters. Furthermore, within these general categories, the range and variability of the models that must be analyzed to determine the appropriate conversion factor is very large. The variable characteristics are: input rate, storage volume, storage tank geometry (short, standard, tall), control systems (standing pilot, electronic ignition, single thermostat, multiple thermostat), venting (natural draft or power vented), technology (non-condensing or condensing) and basic type (storage or tankless) Attached is spreadsheet which is our initial attempt to identify the different types of water heaters that will need to be tested to determine the proper conversion factor. This matrix is still a work in progress and we expect other specific types of water heaters will need to be added to capture the complete range of water heaters that will be tested to the UED test procedure. We must emphasize that in conducting the analysis to determine the conversion factor, multiple tests will be required of each unique type to quantify correctly the difference in results between the current efficiency test applicable to the model and EF resulting from the UED test procedure. We do not agree with the proposal to eliminate the provision that allows electric water heaters that are identical except for different input ratings to be rated based on testing of the model with the standard input rating. The testing burden imposed by the elimination of the current 7.2 is very large. All manufactures of residential electric resistance storage water heaters offer variations of the basic model with heating elements that differ from the standard element(s). The number of optional element offerings may be 10 or more. The option of non-standard elements is offered for most electric storage water heater models. This proposal could raise the current test burden for this type of water heater by tenfold. The design and insulation characteristics of the unit with non-standard elements are the same as the model which was tested with the standard input ratings. The NOPR does specify different SUTs based on the first hour rating of the water heater. However, that change does not warrant the elimination of this provision. The first hour rating and energy factor for units that are equipped with different input ratings can be addressed in a manner similar to the current provision. The only change that requires some modification is the circumstance where a unit with input rating lower than the standard input and which has a first hour rating that would place the unit in a lower FHR bracket requiring a SUT different then the SUT applied to the standard input model. There are some models with FHRs that would require them to be tested to the average usage pattern. In some cases, the amount of the first draw will still require the model to be tested to the same usage pattern. In other cases the amount of the first draw will drop into the bracket that requires testing to the low usage pattern. However, the EF for this circumstance can be calculated to provide a sufficiently accurate estimate of the EF for that unit tested with the different SUT. We are developing a recommended revision of 7.2 which will be provided as a supplement to these comments.
Page 8 of 9 We are confident that DOE appreciates the significance of this rulemaking. We trust that DOE also recognizes that there a many ramifications of the UED test procedure that will affect other regulations to which manufacturers have to comply, both within DOE and as specified by other regulatory agencies. A significant factor in addressing this complex change is the schedule for implementing this rule and others that will be required to change because of the UED. Two such examples are the FTC EnergyGuide labeling rules and the EPA Energy Star specifications. Therefore, we request DOE to consider these ramifications in establishing the implementation date for the UED test procedure. Furthermore, it would be most helpful to our members, as well as others interests, to be provided with information on the status of DOE s activities to work with other regulatory agencies to inform them of the pending changes of the UED test. If available that information should include DOE s efforts to assist the agencies in assessing the effect of the revised test and in establishing a schedule to amend the pertinent regulations or specifications. We appreciate this opportunity to provide comments and participate in this rulemaking. Respectfully submitted, Frank A. Stanonik Chief Technical Advisor Attachments First Hour 125F Tests Residential Water Heater Histograms Conversion Factor Analysis Matrix
Page 9 of 9 First Hour 125F Tests - Electric Electric Storage 40 Low, @135F @125F % Difference Std Tall 59 55-6.7 50 Low 64 61-4.7 Std 62; 56 60.6; 61-2.3; +8.9 Tall 67 62.1-7.3 First Hour 125F Tests Gas & Oil Type Volume Height Input FHR Tests (kbtu/h) @135 F @125F % Difference Gas 30 Low 30 50.8 52.7 +3.7 Storage Tall 32; 32 53.5; 50.2; 63.0 47.8; 45.5; 55.0-10.7; -9.4; -12.7 40 Low 40 68.0 75.0 +10.3 Tall 40; 38 73.0; 77.0 61.5; 68.0-15.8; -11.7 50 Low 40 85.0 77.0-9.4 Tall 40, 40; 38; 90.9; 87.4; 95.0; 81.0; 81.8; 85.0; -10.9; -6.4; -10.5; 50; 60 93.0; 98.0 83.0; 113.0-10.8; +15.3 Oil Storage 30/32 Std 104; 104 153; 175 150; 130-2.0; -25.7