Newsletter

2019 Residential Performance Method is not a Magic Bullet

One of the most interesting aspects of our work as energy analysts is that every three years the Energy Code changes, and we have to learn a whole new set of rules and “tricks” to help our clients meet the Energy Code. With each passing code change, this becomes more and more challenging to do.

The 2019 Energy Code saves about 7% more energy from energy efficiency measures than our current 2016 code or about 53% more including the new solar PV requirements. Translated, that means it will be harder for us to get your projects to pass, especially new home construction. Many of our current go-to credits have become part of the baseline performance method energy budget, and that means they are essentially required to pass the new code.

New Energy Design Rating (EDR) Compliance

Even the way in which performance software evaluates pass or fail for new homes has changed. For new homes going for permit starting on January 1, 2020, we will have to show compliance using two different metrics. The familiar TDV energy that we are used to still shows up on the CF1R, but now compliance is based on EDR (Energy Design Rating). EDR is measured on a scale from 100 to 0. 100 represents a house that wastes energy and is far worse than California Title 24, while zero represents zero net energy. In our Energy Code, a low EDR is better than a high EDR. California EDR compliance has two parts, the “Efficiency EDR” and the “Total EDR”. Each part must pass independently, and we will not be able to ‘transfer’ credit from one side to the other.

In simplest terms, the Efficiency EDR is based on the energy efficiency of the materials and equipment that will be used to build the home. Energy efficiency has always been part of code compliance, and we will still be allowed to “trade off” sub-standard design features (like not using rigid insulation on the walls) for features that perform better than the standard design (like using a high efficiency tankless water heater). What’s new is that compliance for these building efficiency measures is converted from TDV energy use to the Efficiency EDR.

The new Total EDR equals the Efficiency EDR minus EDR credits for solar PV and battery storage. The standard Solar PV EDR credit is based on a solar PV system that is estimated to meet the electricity needs of the house. The proposed Solar PV plus Flexibility EDR credit is based on the proposed solar PV system plus grid flexibility measures such as battery storage.

Efficiency EDR and Total EDR must comply independently from each other, and for a new home to pass, it must pass both categories. We cannot usually take extra credit in one area and transfer it to the other area.

Changes to Available Compliance Credits for 2019 Code

In the 2016 Energy Code, adding solar PV or using HERS-verified QII (quality insulation installation) were powerful compliance credits to trade off against less efficient measures. You could call them our magic bullets! Under the 2019 code, these two items become part of our new performance baseline – meaning no more credit.

The envelope requirements for residential construction are not getting any easier for projects either. New wall construction is now compared to a 2×6 frame wall with R-21 + R-5 continuous rigid insulation (0.048 U-Factor). This used to be a wall that could gain a little compliance credit. As you can imagine, it will be more difficult to get a project to pass if we choose not to include rigid on the walls. To gain credit again in this envelope feature, we may be looking at using new high density R-23 batt in 2×6 wood frame walls or spray foam as an insulation choice. The good news is that roofs and floors see little to no change.

High performance glazing, a feature we like to use, has also experienced a tightening of the prescriptive U-Factor and SHGC. Those prescriptive values are what we are compared to in a performance model. That means if we want to gain credit with glazing, we are looking at using numbers that are lower than 0.30 U-factor and 0.23 SHGC. Another new requirement is that solid doors will be compared to an NFRC-rated solid door standard U-factor of 0.20. The problem is that at the time this article was written there were very few NFRC-rated solid doors. What does this mean to you? If your project has solid exterior doors, we will use a default setting unless you are sure your door will be NFRC-rated. The default value will be a compliance penalty that we will have to overcome by doing something else in the project better.

Where can we still turn for some credits? The home’s mechanical systems can be a great place to gain some credit. Installing a high efficiency tankless water heater is always a great place to start. If the client would like a furnace and AC then let’s look at making both of those products high efficiency.

There’s more good news when it comes to non-gas mechanical options. Under our new code, we will be able to use an electric heat pump water heater and not take a penalty for the tank if it is a NEEA Tier 3 rated piece of equipment. While we have always been able to get credit for high efficiency ducted heat pumps for space heating and cooling, we will soon be able to gain some credit for the ductless mini-split systems that are so popular in smaller spaces, such as ADUs, where a traditional furnace would be way too big.

The bottom line, and what I hope you take away from this, is that we must work smarter with this code change. We need to have frank conversations with our homeowners and contractors about bridging the gap between what they want to do and what must be done to meet code. By bringing Gabel into the picture early in the process, we can work with you to come up with compliance options. By doing this in the early stages of design, you, the owners, and the contractors can investigate the costs associated with these options, and choose a compliance path that works for the project.

 

Article written by Michelle Austin, Manager, Residential/Senior Energy Analyst
First published in the Gabel Energy Summer/Fall 2019 Newsletter