CHBA Comments for the 2024 Fall Public Review National Construction Codes 

Potential Consequences of High-Performance Homes

NBC20 Div.B 9.36.2.7., NBC20 Div.B 9.36.5.3., NBC20 Div.B 9.36.7.3.

WHAT:  This proposed change limits the solar heat gain coefficient (SHGC) for windows and glazed doors in the prescriptive path for energy efficiency to reduce the risk that compliance for energy efficiency increases the risk of homes overheating in the summer. Significant revisions to the PCF make the requirement more flexible and less stringent by setting the maximum SHGC values based on climate zones and over four different categories of window-to-wall ratio (rather than three). 

WHY:  Overall, this change is a result of addressing unintended consequences of the 2020 code changes and CHBA had advocated for these changes. Furthermore, the revisions after the first public review came in large part due to CHBA comments. The revisions mean less stringent requirements especially in the north and for homes with up to 22% window area. 

Impact/Cost to Industry: Overall positive impact. The change resolves a number of issues with the peak cooling requirement in the current energy performance path. According to Codes Canada, the difference in manufacturer s suggested retail unit price is $100 between low- and high-SHGC windows in a double-pane vinyl casement. However, builders would need to assess the local impact based on which SHGC specs they use in their projects and what the revised change would require them to use.

Support with Modifications:

The following is a result of consultations with CHBA members across the country: 

CHBA generally agrees with the proposed measures and suggests the following improvements:

For the proposed changes to the prescriptive requirements: 

We would suggest that with recent developments on requiring mechanical cooling in the majority of all homes (2025-9.33.3 in PCF 2061) dwelling units required to be mechanically cooled should be exempt from the requirement for a maximum SHGC based on climate zone and fenestration-to-wall ratio in 9.36.2.7. as is done in the performance path. We suggest inserting "Where mechanical cooling is not required according to 2025-9.33.3.  " at the beginning of proposed Sentence 9.36.2.7.(2)-2025 to make sure that the limits on SHGC only apply where no other mitigation measure against overheating is installed. 

The revision from to 110% to 100% in Sentence 9.36.5.3,(8) can be confusing and misunderstood to mean doubling. We suggest reinstating sentence 2020-9.36.7.3.(2) The peak cooling load for the proposed house shall not be greater than the peak cooling load for the reference house. and deleting the percentage. (check that we don t want to keep the 110% or exceed by 10% )

For the proposed changes to the performance-based requirements:

We suggest adding the prescriptive compliance method (selecting the Maximum Solar Heat Gain Coefficient according to Table 9.36.2.7.B) as an option in the performance path. A new clause 9.36.5.3.(8) c) or, c) solar heat gain coefficients conforming to Table 9.36.2.7.B. 

We would like to resubmit our comment from the previous public review, which according to our information - has not been acted on and which has recently received some more traction during the discussion of PCF 2061 namely that different calculation tools may calculate cooling loads quite differently.  We note that there is no explanation in this proposed change on how to calculate the design cooling intensity in W/m . We assume it is the modeled peak cooling load per conditioned volume, but we are also aware that CSA F280 issues a cooling load for the summer design conditions and that other HVAC design tools exist. We suggest explaining the simple calculation in the appendix note and clarifying that design cooling loads from any tool are acceptable or whether it has to be the value used in the performance compliance software: The design cooling intensity can be calculated by dividing the modeled peak cooling load by the conditioned volume of the dwelling unit. The peak cooling load can be established by the same modeling tool used for code compliance or any other HVAC design tools compliance software. 

NBC20 Div.B 9.27.2. NBC20 Div.B 9.7.6.1. NBC20 Div.B 9.27.3.

WHAT:  This proposed change introduces a new requirement for sill protection under all windows and doors.   while the current code requires sill protection in some but not all regions (via the 2019 edition of the CSA 440.4 Window, Door and Skylight Installation referenced in Part 9). 

Note that a second proposed change (PCF 1951) recommended for adoption in the 2025 NBC earlier this year would need to be considered in this context as it deals with the same detail and allows for less insulation in the RSO so that any water in this space can drain to the outside.

WHY:  The current requirements in Section 9.27 of the National Building Code of Canada (NBC) has led to face-sealing of windows and doors that prevents, rather than allows, drainage of the rough stud openings. Home warranty providers have reported that water ingress at doors and windows is a serious issue.  This issue is of even greater concern when additional insulation is installed in walls further reducing the envelope s drying potential, as would be required for compliance with higher energy performance tiers. Water ingress at doors and windows was also identified as a critical issue that needed to be resolved prior to the implementation of the 2020 tiered energy-efficiency requirements. 

Impact/Cost to Industry: Both changes (PCF 1950 and 1951) may have a significant impact depending on current practice. A simple survey established that current practice across the country varies considerably as it relates to these two proposed changes and how great their respective impact would be.

Where current practice does not include the proposed detailing, significant industry education and training will be required to ensure proper details for the protection at the sill and head flashing are developed by designers and implemented and inspected in the field. This will be a significant change to the industry in those regions and will take time to change industry practices, and some installers may be reluctant to change their practices if they have not encountered problems. 

Do Not Support:

The following is a result of consultations with CHBA members across the country: 

Process and Timing Concerns 

While CHBA recognizes the importance of addressing water ingress at doors and windows in the Code, and promotes continued education and training on the CSA 440.4 installation standard and best practice requirements, our members are concerned that the proposed requirements could result in even greater confusion and potentially lead to even more problems at the wall/window interface than what is currently being reported. CHBA is in the process of gathering more input from our members. 

Although, water ingress around windows was identified as a critical issue needing to be resolved before the 2020 tiered energy-efficiency requirements can be adopted, CHBA cannot support this change in isolation because of a substantial code development process error of not providing PCFs 1951 and 1950 in the same public review. We ask that the CBHCC submit both PCFs (1950 and 1951) together or combined into a single PCF to the ad-hoc public review in Jan/Feb 2025.

         The two proposed changes are dealing with the same construction detail in homes and relaying the two proposals to industry and discerning their respective impact separately is very difficult if not impossible. 

         In addition, a wholesome discussion of window/wall detailing should have involved consideration of flashing requirements in all national and provincial codes, since the goal is to develop harmonized requirements that can be adopted by each province and territory.

In terms of timing, we would like to point out that the amount and pace of code committee meetings coinciding with the period for this public review (November and December 2024) made it very difficult to conduct in-depth consultations with our members on a single proposed change. 

Simply put, the application of sill protection for all doors and windows and leaving the bottom of a door or window open for drainage is a significant shift for the residential construction industry in many areas in Canada. Additional time is required to consult with our members to consider the real impact of removing the current exemption for all doors and windows from the second plane of protection requirements. 

PCF 1950 (Sill Protection)

1.      The impact analysis states that this change should not result in significant cost impacts compared to the current Code requirements and installation methods used across the country . However, the current code exempts doors and windows in some locations from applying the second plane of protection requirements including sill protection and the actual cost impact of this proposed change is currently unknown. Other types of construction, for example ICF, may require additional preparation measures before sill protection according to the proposed change can be applied. We suggest adding a simple whole-house impact analysis about the cost and benefits of material and labour for this change that is reflective of different construction methods. 

Comments on PCF 1951 (Continuity of Insulation) 

These comments are provided for the record and to show the significant nature of the comments. They support our request for a combined re-submission of PCF 1950 and PCF 1951.

1.      Builders in cold and humid climates are concerned about the potential for condensation forming on window frames if the RSO is not fully insulated on all four sides including the sill, which in turn could create challenges for builders in meeting consumer expectations and having to meet the performance guidelines set by home warranty providers. Some of our members have encountered challenges when they used backer rod and caulking to seal RSOs without insulating the RSO and had to insulate this space afterwards. Builders in areas with high winds have also noted the importance of insulating all four sides of the RSO including the sill. The industry will need assurance this change in practice has been field tested in cold humid climates and that it will not have any negative consequences. 

2.      If NRC or others have already carried out research and field demonstration projects showing that minimal insulation on the jambs and header and no insulation at the sill is adequate in cold / humid climates, this information should have been attached as supporting information to the proposed change prior to public government/industry consultations at the provincial level for requirements already proposed for the 2025 NBC.

Operational Greenhouse Gas Emissions

NBC20 Subsection 9.36.12.

WHAT: This proposed change introduces prescriptive requirements in NBC Section 9.36. to minimize excessive emission of operational greenhouse gases. It has been revised to correct modeling errors and to align with the points-trade-off method (instead of energy tier levels in general) in the prescriptive path.

WHY: The 20205 codes will regulate the emissions coming from the home energy use for space conditioning and water heating. The alignment with energy points method offers more design flexibility. While the revisions to correct the modelling errors was necessary to align the performance path and the prescriptive solution, it has resulted in more stringent requirements in some cases, than previously proposed. 

Impact/Cost to Industry: High Impact. On the positive side, a prescriptive method was introduced in this code cycle rather than being pushed to the next. 

Generally, and for all GHG related propose changes, the proposed requirements will have a more significant negative impact for builders in Provinces that rely largely on fossil fuels for electricity generation (AB, NS, SK, NB). The incremental cost will depend on the energy conservation measures selected by the builder to reach the specified points and GHG emissions level. Codes Canada estimates the incremental cost of using a Tier 2 building envelope (climate zone 4 with a 200m floor area) with an electrically operated air source heat pump and heat pump water heater as $20,738.

Support with Modifications:

The following is a result of consultations with CHBA members across the country: 

CHBA supports prescriptive solutions, however, we note our general disagreement with the entire set of proposed GHG requirements, which are discriminatory to builders in different regions based on provincial emission factors, over which builders have absolutely no control. An all electric, high-performance dwelling unit constructed in AB, SK or NS would not reach above level C, while a low- to mid-performance dwelling unit construction in MB, BC or QC would easily reach a level A performance with no additional energy points necessary. This makes housing in the high emission provinces less affordable unless utilities act, which clearly speaks to the need for policy and regulatory action at the utility level, but does not make a case for regulating the building industry beyond reducing the energy use.

For the proposed change 2026 we note the following improvements: 

1) We note that the problem statement mentions the contributions of building energy use to GHG emissions in Canada, but neither the justification nor the impact analysis includes by how much these changes will reduce emissions (i.e. the benefits of this regulation). We note that none of the GHG changes therefore comply with the Impact Analysis required by the Policies and Procedures. We suggest that an estimate of the benefits of applying the GHG requirements is added to the impact analysis and that the estimate includes discount factors for addressing only new construction (not existing) and for the fact that new homes in provinces with hydroelectric energy production will only minimally contribute to any emission reductions. We also note that the whole-house costing was established based on climate zone 4 and suggest performing and reporting costing on all climate zones, including the colder climates.

2) Using the default, average, future-projected emissions factors for this prescriptive method introduces a bias in emission factors between gas and electricity (renewable content is captured in electricity, but not in gas) and any potential differences in emission factors issued by a province for the performance path would necessitate that a province generates their own prescriptive solution. We suggest that this be clarified in an appendix note to the Table: The emissions factors used to establish this prescriptive method (see Sentence 2025-9.36.11.6) include renewable energy sources under electricity emissions, but not under gas. Where a province or territory establishes its own emission factors for use with the performance path, the regulatory outcome may be different between the performance path and the prescriptive method in 2025-9.36.12. unless the province or territory also re-generates their own prescriptive solution. 

Reference Documents

NBC20 Div.B 1.3.1.2., NFC20 Div.B 1.3.1.2., NPC20 Div.B 1.3.1.2., NECB20, Div.B 1.3.1.2.

WHAT:  The proposed change proposes updates to 186 referenced documents in all national codes to their respective newest edition. Among them are proposed updated editions for 

         Truss Plate Institute of Canada Guideline, 

         CSA C22.1, the Canadian Electrical Code, 

         ASHRAE 140 "Method of Test for Evaluating Building Performance Simulation Software," 

         CSA F326 Residential Mechanical Ventilation Systems , which was last updated in 1991. 

         Various standards for energy performance ratings of heat pumps and heat/energy recovery ventilators

         CSA standards for structural wood design and concrete materials.

WHY:  Updates to editions of referenced documents are regularly proposed by Standards Development Organizations and/or other organizations to make sure the information in codes is on up-to-date.  

Impact/Cost to Industry: Unlike other proposed changes, the list of updated reference standards does not include an impact analysis or any information on cost to industry and standards developing organizations themselves are not required to provide an impact analysis. While the majority of updates contain minor revisions, some proposed document updates may have a high impact, such as the updating of the Truss Plate Institute of Canada (TPIC) Guideline for truss fabrication as it would have negative implications on factory builders who fabricate their own trusses and who already employ quality assurance systems and the adoption of this guideline would result in unnecessary costs and inspection processes.

CHBA has submitted two separate comments: 

Comment 1: Do Not Support:

The following is a result of consultations with CHBA members across the country: 

We do not support this proposed change in its entirety: 

         CHBA notes that no impact analysis is provided for any of the referenced document updates. This may be a contravention of the Policies and Procedures under which the national codes are developed. As the Standard Development Organizations are also not required to assess that the benefits of their revisions exceed the incremental costs, this proposed change contains potentially 186 cost-increasing measures that will not be accounted for.

         Furthermore, a proper review by general code users would be very costly as many of the new editions of referenced documents are still not available free of charge. We recognize that some standard developing organizations are at the forefront of providing no-fee access but that others offer difficult to navigate view-only features. 

We cannot support an unqualified reference of a non-consensus based, good practice guideline in Division B and offer the following modifications on this specific update:

         Truss Plate Institute of Canada (TPIC) Guideline: CHBA does not support the updated version of the TPIC Guideline, which is a non-consensus-based, best-practice guideline referenced as such as in Part 9 because it unfairly penalizes factory builders who fabricate their own trusses and already operate under a quality system/certification scheme. Those factory builders would have to implement another, secondary quality, and certification system for truss fabrication (in addition to CSA A277 quality and certification system for the entire building). CHBA has asked at every level of the committee deliberations for evidence of failures and has not received any responses other than anecdotal evidence from the 90s in the US . CHBA strongly recommends that this guideline not be updated to its newest edition or that the TPIC guideline is removed as a such as reference of best practice from the code.

Comment 2: Support with Comments: 

We offer the following comments on the specific updates:

         Canadian Electrical Codes: While CHBA recognizes that the Canadian Electrical Code is being adopted independently by provinces and territories, we note that the calculations in the 2024 edition of Electrical Code for the consumer service panel size may not recognize the lower energy loads required by high-performance (i.e. highly energy efficient) buildings, which are now covered by requirements in this Code.  CHBA strongly recommends that NRC researches load profiles of high-performance homes and works with CSA and the CSA C22 Part 1 committee to review the size calculation requirements for electrical panels to avoid unnecessary service size upgrades.

         We note that the new edition of the ASHRAE 140 standard is only applied to the NECB and recommend that its application be expanded to include Section 9.36 of the National Building Code once it has been confirmed that the most commonly used modelling tools can conform with the criteria in ASHRAE 140 - 2023.

         Finally, while CHBA supports the update to CSA F326, we note that this standard called up in Part 9 of National Building Code refers to CSA F300 Residential depressurization for the depressurization related requirements that were removed from CSA F326 and CGSB 51.71 (2005) still referenced in this proposed change has yet to be replaced. The review of CSA F300 and the potential replacement of CGSB 51.71 with this up-to-date standard should be made a high-priority.

Energy Modeling Software Requirements

NECB20 Div.B 3.1.1.5., NECB20 Div.B 3.1.1.7.(4), NECB20 Div.B 8.4.2., NECB20 Div.B 8.4.3.9

WHAT:  This proposed change for the National Energy Code updates the edition year of ANSI/ASHRAE 140, "Method of Test for Evaluating Building Performance Simulation Software," to 2023, which means that energy modeling software will now have to meet tolerance criteria for the metrics calculated by the software (e.g. heat loads, cooling loads). This would also apply to exceptional calculation methods (e.g. external spreadsheet data generated as input for energy models).

WHY:  The 2011 edition of this referenced standard includes test cases for the evaluation of building performance software but does not include information about the acceptable calculation results for those test cases. Providing pass/fail criteria for any energy modeling software levels the playing field.

Impact/Cost to Industry: Low impact to home builders who comply with Part 9. Possible impact to builders of large residential, mixed-use or non-residential buildings falling under the NECB. Codes Canada considers this to be cost-neutral.

Support with Comment:

The following is a result of consultations with CHBA members across the country: 

CHBA welcomes the updating of the reference to the newest ASHRAE 140 standard edition and is disappointed that the standard update was not extended to the use of the software in Part 9 where a level playing field and increased consistency between energy models may also be beneficial. However, CHBA also appreciates that it is important to confirm the modelling tools most commonly used to demonstrate compliance with Part 9 energy performance targets actually meet ASHRAE 140 tolerances before moving ahead with this change in Part 9.

Documentation on Exceptional Calculation Methods

NECB20 Div.C 2.2.2

WHAT:  This proposed change establishes requirements for documentation on exceptional calculation methods (eg. use of external spreadsheet calculations) where energy modeling software cannot be used.

WHY:  This change supports the updating to the newest edition of the ASHRAE 140 standard. Failing to update documentation requirements could create enforcement difficulties for projects where energy modeling software cannot be used or needs additional input that has been generated externally to the model (eg. specific shading devices or innovative technology).

Impact/Cost to Industry: This change has no impact for builders using Part 9 energy compliance. Codes Canada considers this to be cost-neutral and cost is not typically addressed in administrative requirements. 

Remain Silent - No Comment:

[We did not submit a comment.]

Encapsulated Mass Timber Construction

NFC20 Div.B 5.6.4.3.

WHAT:  This proposed change revises the degree of protection of mass timber ceiling elements in Encapsulated Mass Timber Construction (EMTC) while a building is under construction. This proposed change would harmonize the National Fire Code (NFC) requirements with those of the NBC for finished mass timber buildings to introduce an option to allow 100% of the surface of mass timber ceilings within a suite to be exposed while the building is under construction.

WHY:  The current encapsulation requirements during the construction of EMTC buildings have been difficult to implement. Moisture in open construction sites has affected the gypsum protection, as well as costs associated with the onerous requirement. This change also aligns with recent revisions to another change that allows 100% exposed mass timber ceilings (PCF 1870). 

Impact/Cost to Industry: This relaxation has a positive impact on mass timber construction as it will give builders multiple prescriptive solutions to protect their EMTC buildings during construction, rather than just encapsulation protection, which may not be practical in all parts of Canada. The expectation is that costs would either remain the same or be reduced due to the harmonization of requirements.

Remain Silent - No Comment:

[We did not submit a comment.]