California Association of Building Energy Consultants

Ideas to Consider for Residential Buildings Attempting to Meet the 2019 Energy Code, Effective January 1, 2020

Design Review

"The best buildings result from an integrated design process: a continual, organized collaboration of a team of professionals that may include architects, designers, a variety of engineers, contractors, subcontractors, Energy Consultants, Building Inspectors, HERS Raters and many others. As 2020's Zero Net Energy goals approach, the need for early and regular collaboration between these professionals is essential."

— from CalCERTS, a HERS Company

As a result of this fact, CompuCalc is now offering "Design Stage" Energy Analysis. This will make it easier to integrate energy compliance requirements into the drawings and save costs of re-doing drafting & design. Call or ask today for a fee structure that includes a "Design Stage" Energy Analysis.

Energy Compliance is not just a form needed to obtain a building permit. Energy compliance is a process that begins at design stage and ends at the final building inspection. Elizabeth Smithwick of CompuCalc consults and guides through the entire building process as needed. CompuCalc's fee structure is built on this premise.

Mechanical Systems

  1. Consider Variable Capacity Heat Pumps, ducted or non-ducted, as the HVAC system choice. New credits are available for these system types. Additional information from the HVAC contractor or HVAC designer is needed for the energy analysis. This information can be found in this article: Is a Variable Capacity "Mini-Split" Heat Pump (VCHP) your choice for heating a newly conditioned residential space?
  2. Consider a balanced HVAC ventilation system with the use of a HRV/ERV unit. Information needed for energy analysis is the unit's CFM, wattage, and recovery efficiency. Note these units must be listed with the California Energy Commission's Title 20 Division and with the HVI directory. This system will need 3rd-party verification from a HERS Rater as it will be the system used to meet the indoor air quality requirements of the Title 24 Part 6 Energy Code. A HERS Rater can be found by contacting the installing HVAC contractor, CalCERTS, or the CHEERS.
  3. Consider preparing an HVAC System & Duct Design during the design phase. This will help define energy ratings for equipment; consider best design for duct systems supply and return air and duct length; and determine if other energy credits would be available based on the proposed duct design. CompuCalc can help in this area. Joel Smithwick, HVAC contractor, provides residential mechanical designs using ACCA Manual J (as required by the CA Building Energy Efficiency Standards — see below), Manual D, and Manual S:

    Section 150(h) Space-Conditioning Equipment.

    1. Building Cooling and Heating Loads. Building heating and cooling loads shall be determined using a method based on any one of the following:
      1. The ASHRAE Handbook, Equipment Volume, Applications Volume, and Fundamentals Volume; or
      2. The SMACNA Residential Comfort System Installation Standards Manual; or
      3. The ACCA Manual J.
      The cooling and heating loads are two of the criteria that shall be used for equipment sizing and selection.
  4. Water Heating: Specify gas-fired, tankless water heaters. Under the 2019 Energy Code a gas-fired, tankless water heater is the standard and the standard energy budget is set using this type of water heater. Therefore, any storage type water heater will be seen as below the budget and other energy measures will be needed to balance the energy budget. Electric water heating (tankless or storage) will continue to have a large negative effect on the energy budget, unless it is an electric heat pump water heater with an energy rating of 3.2 or better.

Building Envelope

Consider specifying a 3rd-party HERS verification for a Building Envelope Leakage Test. The default setting for this is currently 5.0 @ 50 Air Changes per Hour (ACH). With the use of a product such as AeroBarrier the testing target may be reduced to as low as 2.0 @ 50 ACH which results in a nice credit that can offset other energy requirements. (Please note a specified air leakage of 1.7 or less will require a balanced mechanical ventilation system [see #2 above] in order to provide proper indoor air quality.) For example, some energy modeling analysis with the use of a 3rd-party HERS verified Building Envelope Leakage below 5.0 @ 50 ACH credit, has resulted in allowing the removal of insulation at the underside of the roof deck in an attic construction; and/or allowed a return to 2x4 wall framing instead of 2x6 wall framing; and/or allowed the removal of a Quality Insulation Inspection (QII), a 3rd HERS Inspection.

"Additionally, a tightly sealed home can provide greater comfort, a quieter home, lower utility bills and reduction of pest infiltration", per Micah Seierstad of CalBarrier, an Aero Seal dealer/installer. Get more information about Aero Barrier …. Below is a quote from the AeroBarrier website:

"Historically, energy savings derived from building envelope enhancements have been challenging to achieve. At the same time, standards for envelope tightness are escalating. AeroBarrier, a new and innovative envelope sealing technology is transforming the way residential, multifamily, and commercial buildings seal the building envelope.

AeroBarrier can help builders meet any IECC, Energy Star, or passive house requirement more consistently and more importantly, more cost-effectively than traditional envelope sealing methods. AeroBarrier is a proprietary technology that takes the guesswork out of sealing the envelope.

We guarantee the results, whether you need 3ACH50 or passive house requirements! AeroBarrier is a first of its kind, cutting-edge envelope sealing technology for commercial, residential and multi-family applications with tested and proven results."

In conclusion, a building envelope leakage test and use of the AeroBarrier product work together to provide significant credits in energy compliance, thereby allowing reduction of other energy features.

Additionally, one more feature that AeroBarrier can provide is a path of compliance for a failed Quality Insulation Inspection (QII). The AeroBarrier product can be applied at the end of construction as well to achieve passing of the 3rd-party QII requirement.

As always, I am available to discuss the process of meeting the California Energy Code for any building project. Contact me …