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Electrical Submetering in California:

Fact, Fiction and Folly

Electrical submetering is now required for many residential and commercial buildings in California. What does this mean for building owners, and how can they implement tenant submetering while avoiding costly mistakes?

What is Electrical Submetering?

Many commercial and residential buildings use a single "master meter." Electricity comes into a building at bulk rate prices from the Utility, and landlords bill tenants for electricity based on flat fees or formulas derived from the space they occupy. Occupants pay for electricity as part of a monthly bill, but their energy use is not individually monitored or tracked.

Electrical submetering  is the measurement of consumption after the master meter. Submeters (also referred to as power meters, electrical meters, and energy monitors) are installed after the master meter to measure individual electrical load.

Graphic of electricity coming into a building's Master meter and then measured after the panel by a multi-unit Sumter
Submeters can measure energy use for tenants, departments, building equipment, or any other electrical load.

The Benefits of Electrical Submetering

Submeters allow for the granular measurement of energy, right down to the individual circuit. Building owners and property managers can pinpoint energy use, identify failing equipment, and allocate costs fairly by installing submeters. Tenants pay only for the electricity they use, are accountable for their consumption, use less energy, and lower their electricity bills.
Reduce Energy Use, Save Money
There are several strategies for reducing energy costs, but few are as compelling and fundamental as submetering. Many studies have shown that using submeters to allocate charges based on actual energy use is one of the most effective ways to reduce consumption. 

One of the most exhaustive examinations of applying electrical submetering to commercial buildings was undertaken by the U.S. Department of Energy as part of the Federal Energy Management Program (FEMP) in 2007. This study showed that merely installing meters resulted in a 2% reduction in energy use through the Hawthorne Effect. [1]

But that was just the start. FEMP found that submetering aspart of a coherent, continuous commissioning program of benchmarking, analysis, and remediation can result in 15% to 45% savings. [2]
Win, Win and Win!
When tenants pay directly for their energy use, overall building consumption drops on average by 20%. That's an impressive saving that's comparable to installing an entire building automation system or changing all the windows in an office tower — at a fraction of the cost. 

Put another way, for every five buildings that are submetered, an entirely new building can be powered from the saving.
For every five buildings that are submetered, an entirely new building can be powered from the savings alone.
With Electrical Submeters installed...
  • Tenants win by saving money and reducing their energy use.
  • Landlord’s win with considerably lower energy and operational costs.
  • The environment wins with significant reductions in greenhouse gas emissions.

What Laws Govern Electrical Submetering in California?

California law requires the use of State-approved submeters when billing tenants. Additionally, new regulations under California’s Code of Regulations introduce minimum requirements for electrical service metering — meaning many residential and commercial buildings are now required to submeter electricity.  
Meter Approval
Before a submeter can be used for billing applications in California, it must be evaluated and endorsed by California's Department of Food and Agriculture through their California Type Evaluation Program (CTEP). It is illegal for a device to be used for tenant billing if it has not received Type approval from the Department. 

The purpose of the evaluation is to certify that the design and performance of the meter meet all relevant California laws and regulations. Tests focus on accuracy, operational effectiveness, required markings, and fraud prevention features. Upon successful CTEP evaluation, a Certificate of Approval (COA) is awarded. 
What is Title 24, Part 6?
California has long been a leader in energy conservation, first adopting "The Building Energy Efficiency Standards for Residential and Non-residential Buildings" in 1976. These standards have since evolved into Title 24 of the California Code of Regulations, also known as the California Building Standards Code, or "Title 24".

Title 24 lays out regulations that govern the construction and redevelopment of residential and non-residential buildings in California. The Standards contain energy and water efficiency requirements for newly constructed buildings, additions to existing buildings, and alterations to existing buildings.

Parts 6 and 11 of Title 24 address the need for regulations to improve energy efficiency and combat climate change. Other portions of Title 24 include building code, electrical code, fire code, and more. 

The most significant efficiency improvements to the Standards came in 2019 and included alignment with ASHRAE 90.1 2017. ASHRAE 90.1 has been a benchmark for building energy codes in the United States and a fundamental basis for codes and standards worldwide for more than 35 years. ASHRAE 90.1 is also an industry-standard referenced by the U.S. Green Building Council (USGBC) in the LEED building certification program — and frequently used as a baseline for comparison during energy retrofit projects.
What Does This Have to do With Submetering?
In 2016, Title 24, Part 6 introduced the concept of measurement and verification (M & V) to track and analyze code compliance efforts. Section 130.5(a) & (b) of Part 6 have service metering requirements that include user-accessible metering of total electrical use from the whole building down to branch circuit monitoring — commonly referred to as "disaggregation of loads”.

The submetering requirements for new or substantially remodelled non-residential, high-rise residential, and hotel/motel buildings are:

Section 130.5 (a) Service Electrical Metering Requirements: "each electrical service shall have permanently installed user-accessible metering of ‘total energy use’ as per the table below."
Meter Type
Services Rated 50 kVA or Less
Services Rated > 50 kVA and <= 250 kVA
Services Rated > 250 kVA and <= 1000 kVA
Services Rated > 1000 kVA
Instantaneous (at the time) kW Demand
Historical Peak Demand (kW)
Not Required
Not Required
Resetable kWh
kWh Per Rate Period
Not Required
Not Required
Not Required
The 50 Kilovolt-amps (kVA) entry-point is meant to target facilities of 5,000 square feet and larger. However, much smaller projects also can be affected depending on their heating and cooling loads. Understanding a building's energy intensiveness is key to determining a path towards Title 24 compliance.
Section 130.5(b) Separation of Electrical Circuits for Electrical Energy Monitoring: "electrical power distribution systems shall be designed to permit the disaggregated measurement of electrical load energy uses downstream from the service meter.”
Protection for Tenants
Many safeguards have been built into California's energy standards to protect tenants. If the use of submeters results in tenant billing, several processes and procedures must be followed, including those related to:
  • Visibility of energy used by tenants
  • Disclosure of the cost of electricity to the building owner
  • The types of meters that are approved for tenant billing
  • Meter sealing requirements

How Much Cost and Effort is Involved?

Submetering has developed considerably from its humble origins — with several advancements that have made circuit branch monitoring reliable and economical.
The More the Merrier
The evolution of multi-point electrical meters has created a cost-effective way to meet Title 24 Part 6, 130.5(b) requirements. Multi-point meters can isolate and monitor energy use by circuit, aggregate circuit-level data in any combination required, and easily adjust to circuit changes as building organization changes over time. Existing buildings don't need costly rewiring or expensive extra equipment. For new builds, panels can be installed with less labour since no additional time is needed to validate complex layouts.

Multi-point meters have the added advantages of having a much smaller footprint than multiple single-point meters and lower per meter point deployment, integration, and maintenance costs.

Multi-point meters allow for the metering of 6 or more circuits depending on the model and need. They are useful when measuring a large concentrations of circuits and a viable option for multi-load, granular data requirements. Multi-point meters have much smaller footprint than multiple single point meters and lower per meter point deployment, integration, and maintenance costs than single point meters. 
Triacta GATEWAY with Label Card Under Seal
One multi-point meter (in yellow circle) replaces multiple, single-point meters.

Submeters Beware!

While the cost and effort of submetering are well within scope for most building projects, there are several things property managers and building owners need to pay attention to when deploying submetering to meet Title 4 compliance, including:
  • A clear understanding of your building's energy intensiveness, so you know for sure if your facility falls under sections 130.5 (a) and (b) of Title 24 Part 6.
  • Complete knowledge of tenant rights as they pertain to electrical submetering and tenant billing.
  • What precisely needs to be measured for compliance? How should it be measured? How often? Do you need to keep a historical record of energy use?
  • The risks and consequences of non-compliance. Who enforces it? What are the costs of non-compliance? How do you demonstrate compliance?
  • Which meters are approved for tenant billing by the CDFA? 
  • How long can you expect to be able to use a meter? 
  • What happens when technology and communication protocols evolve? Will your chosen meter keep pace?