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What is Efficiency-As-A-Service?

Efficiency-as-a-service is a pay-for-performance, off-balance sheet financing solution that allows customers to implement energy and water efficiency projects with no upfront capital expenditure. The provider pays for project development, construction, and maintenance costs. Once a project is operational, the customer makes service payments that are based on actual energy savings or other equipment performance metrics, resulting in immediate reduced operating expenses. The energy services agreement (ESA) is the most common type of arrangement, but other models such as lumens-as-a-service and energy subscription agreements are also in use.

Efficiency-As-A-Service may be a good fit if your organization...

  • Wants to pursue retrofits across your portfolio without spending your own capital
  • Prefers off-balance sheet treatment for the delivery of efficiency services
  • Wants a pay-for-performance solution where a third party takes on performance risk and provides project management and maintenance
  • Is looking for a financing mechanism with a contract term ranging from 5 to 15 years, with periodic buy-out options
  • Wants a new way to procure energy efficient technologies across your portfolio without the hassle of ownership

To compare efficiency-as-a-service to other financing options that might be a good fit, answer a few questions about your organization.

Energy Services Agreement Structure flowchart

How it Works

This section begins by describing a typical energy services agreement (ESA) because it is the most common efficiency-as-a-service structure. Then the two “Alternative Approach” sections will discuss different structures in comparison with the ESA. Note that efficiency-as-a-service space is rapidly evolving, so many different arrangements are in use, and more are in development.

Under an ESA, the provider enters into the ESA directly with the customer for a contracted period (typically 5-15 years). Before equipment is installed, the ESA provider performs a baseline of the customer’s energy consumption and calculates an upfront estimation of savings. The ESA provider then pays and manages a contractor to install the high-efficiency equipment and help maintain the equipment through the contract period. Once project installation is complete, a measurement and verification (M&V) analysis is performed to determine actual savings compared to baseline energy use. 

The customer then enjoys lower utility bills throughout the contract term. The customer pays the ESA provider a charge per unit of energy saved that is set below its baseline utility price, resulting in immediate reduced operating expenses. The ESA payment can be structured either as a percentage of the customer’s utility rate or as a fixed dollar amount per kilowatt-hour saved. The ESA provider retains ownership of the equipment for the duration of the ESA term and pays for maintenance to ensure reliability and performance. New efficiency measures can be added during the duration of the contract. At the end of the contract, the customer can elect to purchase the equipment at fair market value, extend the contract, or (less commonly) return the equipment.

An ESA can be thought of as an energy efficiency version of the Power Purchase Agreement (PPA), a structure commonly used to finance renewable energy systems. Under an ESA, the customer doesn’t bear the project performance risk since it only pays for savings actually achieved. Instead, the ESA provider bears this risk and gets paid less if the project savings are lower than expected. However, ESAs vary significantly in terms of contract structure, method used for measuring realized savings, and how the customer and provider split performance risk and upside. Some ESA providers are exploring the possibility of combining ESAs with on-bill repayment.

Typically, ESA projects are funded through a combination of equity from the ESA provider and outside debt from a lender. The ESA provider typically forms a special purpose entity (SPE) that owns all project equipment and is repaid by customer payments under the ESA.

An Alternative Approach: The Managed Energy Services Agreement

The Managed Energy Services Agreement (MESA) is a variation on the ESA with a few important distinctions. In a MESA structure, the provider assumes the broader energy management of a customer’s facility, including the responsibility for utility bills. The MESA provider essentially acts as an intermediary between the customer and the utility. The MESA provider will charge the customer an agreed-upon fixed rate based on historical energy consumption, thus protecting the customer from utility rate changes. MESAs are especially of interest in sectors where a “split incentive” between landlord and tenant is an issue, as the structure of the agreement allows MESA charges to be passed through to tenants.

Managed Energy Services Agreement Structure flowchart


An Alternative Approach: Other Efficiency-as-a-service Models

Some providers are offering alternative efficiency-as-a-service models that differ from the ESA and MESA. One example is “lumens-as-a-service,” in which a customer specifies its desired lighting output (which can be framed in terms of footcandles or lumens of light supplied, or other metrics) and the provider delivers a contracted lighting service to achieve those outcomes. Another example is a “subscription agreement,” in which customer payments are based on the function or output of the installed energy equipment rather than measured savings, resulting in a simpler contract. Other models such as “electric vehicle charging stations as-a-service” are also being explored. The “as-a-service” concept can potentially be applied to a wide range of technologies using a variety of structures, and the space continues to rapidly evolve.

Advantages and Disadvantages

Advantages and Downsides

Efficiency-as-a-service allows customers to redirect a portion of their current utility spending to pay for efficiency improvements; ESA payments are based on realized energy and operational savings and set below the current utility price.


Efficiency-as-a-service is designed to be an off-balance sheet financing solution, with regular payments that are treated as an operating expense similar to a standard energy utility bill or PPA.


Efficiency-as-a-service providers pay for periodic maintenance services to ensure long-term reliability and performance of the project equipment. Under a MESA, the customer has a single point of contact and a single payment for all utility expenses and the MESA provider actively manages energy consumption at the facility.


Many providers can bundle together multiple sites that have smaller project opportunities into a single package (e.g., bundle 10 sites with $500,000 projects into a single $5 million service contract).


Providers tend to look for larger project sizes ($1M+) and some will not consider smaller projects (less than $250k), though there are exceptions.


While efficiency-as-a-service can work in leased or owned space, its is typically only viable in leased space if the contract term does not exceed the lease term.


Transaction costs can be high if each deal is heavily negotiated; for more complicated retrofits with no preliminary energy audits completed, deals can take 9-12 months or more to close.

State of the Market

Efficiency-as-a-service is a relatively new but proven structure that has been used to implement multi-million dollar retrofit projects in Fortune 500 companies and major facilities across the U.S. It is most common in the commercial & industrial and MUSH (municipalities, universities, schools, and hospitals) sectors, but it can work for any sector. Efficiency-as-a-service is a flexible financing mechanism that can incorporate a wide range of efficiency measures, including water. Efficiency-as-a-service is often described as part of a broader transition to energy-as-a-service, in which third-parties provide technical, financing, and/or procurement solutions for energy technologies in exchange for a service fee, rather than having the customer purchase the systems outright.

Efficiency-as-a-service is gaining popularity because it overcomes market barriers that other mechanisms do not, and it limits customer performance risk while still providing an avenue for short-term energy and cost savings. With the upcoming Financial Accounting Standards Board changes to lease accounting that will bring operating leases onto the balance sheet, efficiency-as-a-service will likely be one of the few remaining efficiency financing options to be consistently considered off-balance sheet. Efficiency-as-a-service represents part of a larger shift across the industry away from customer equipment ownership and toward an “as a service” model, where the customer does not own the efficiency equipment but instead pays for energy savings or output like a service.

The efficiency-as-a-service market is thought to be growing quickly, but no thorough and up-to-date analysis of current market size has been conducted. Navigant has estimated global revenues from the lighting-as-a-service alone could become $2.6 billion by 2026. A 2012 analysis by Deutsche Bank Climate Change Advisors and the Rockefeller Foundation estimated that more than 100 ESA projects had been completed, with a pipeline for potential ESA projects of approximately $500 million across all firms. These numbers have likely grown substantially since then. Within the Better Buildings program, the Financial Allies completed over $450 million in efficiency-as-a-service projects from 2012 to 2019. Financing small and medium size projects has proven challenging due to high transaction costs, but through aggregation and streamlined business models, efficiency-as-a-service has the potential to help unlock this market which many traditional energy performance contract (EPC) models are unable to address.

Better Buildings Implementation Models

Metrus Energy: Nationwide Deployment of Efficiency Services Agreement

Metrus Energy deployed multi-measure energy efficiency retrofits in BAE Systems facilities with no upfront costs using an Energy Services Agreement (ESA).

AT&T, Redaptive Efficiency-as-a-Service Program

Redaptive partnered with AT&T to implement energy efficiency measures at nearly 650 facilities using an efficiency-as-a-service financing solution, resulting in nearly $20 million in annual energy cost savings.

Citi Riverdale Data Center Energy Services Agreement

Citi used an energy services agreement to deliver efficient electricity and cooling at its London data center. The project is expected to deliver $1.1 million in annual cost savings.

Metrus Energy: Financing Kuakini Medical Center Upgrades with an Efficiency Services Agreement

Metrus Energy's Efficiency Services Agreement structure funded 100% of critical facility improvements and equipment upgrades for Kuakini Medical Center, with a projected 25% reduction in its total annual utility bill.

Citizen Energy uses Efficiency-as-a-Service to Finance Multifamily Properties

Citizen Energy completed projects at two separate multifamily properties with different ownership structures using an efficiency-as-a-service financing solution, resulting in cash-flow positive outcomes since day one.

Learn More About Efficiency-As-A-Service

Efficiency-As-A-Service At-A-Glance

The following table will give you an at-a-glance summary of a typical efficiency-as-a-service arrangement, including a basic description, contract structure, tax and balance sheet implications, contract terms, and market information. Mouse over the ‘?’ next to each attribute for more information.

Basic Attributes
Project Type
Energy Efficiency
Basic Attributes
Applicable Sectors
Affordable Multifamily, Commercial & Industrial, Government, Multifamily, Non-profit, Private Universities / Schools / Hospitals
Basic Attributes
Geographic Scope
Available Anywhere
Basic Attributes
Building Ownership
Leased or Owned
Basic Attributes
Typical Project Size
Typically $250k+
Contract Structure
Contract Complexity
Contract Structure
Parties Involved
Customer, Contractor, ESCO, Financier
Contract Structure
Payment Type
Sometimes Variable
Tax & Balance Sheet
Budget Source
Internal (Opex)
Tax & Balance Sheet
Balance Sheet Treatment
Off Balance Sheet
Tax & Balance Sheet
Tax Deductions
All Payments
Tax & Balance Sheet
Equipment Ownership
Tax & Balance Sheet
Collateral Source
Equipment, discontinuation of service (sometimes), non-payment of utility bill (MESA only)
Contract Terms
Typical Duration
5-15 years; generally does not exceed useful life of equipment
Contract Terms
Typical Close Time
Medium (3-9 months)
Market Attributes
Market Size
Under $3B
Market Attributes
Time in Market
Since the late 1980s