Energy as a Service: the broader model that keeps landing on heat pumps.

1. What Energy as a Service actually is

EaaS is a service-contract framework applied to a building’s energy system rather than to a single piece of equipment. A provider designs, finances, installs, owns, and operates a bundle of energy assets — the specific bundle varies by project — and the customer pays a service fee tied to the outputs those assets produce or the savings they deliver against a measured baseline. The Department of Energy’s Better Buildings Solution Center groups these arrangements under a single taxonomy but stresses that the underlying contracts range widely: efficiency service agreements, energy service agreements, managed energy service agreements, power purchase agreements, and hybrid structures all fall within the family (DOE Better Buildings EaaS taxonomy).

The mental model that works most reliably: the provider sells you a performance outcome, not a machine. Contracts commonly run 5 to 20 years, and payment is structured either as a fixed monthly service fee or as a share of measured avoided cost against a documented energy baseline. Redaptive, one of the more established EaaS operators, describes its model as “pay-for-performance” billing tied to verified avoided energy use, delivered off-balance-sheet with contract terms typically in the 5–20-year range (Redaptive). What distinguishes EaaS from a plain equipment lease is that the provider carries technology-performance risk: if the equipment doesn’t deliver the expected savings, the customer’s payment is typically adjusted rather than the customer being on the hook.

Key idea: EaaS is a service-outcome contract wrapped around a bundle of energy assets. The provider owns and operates the equipment; the customer pays for the delivered energy service or measured savings.

2. Why heat pumps have become the EaaS cornerstone in decarbonization markets

Ten years ago, EaaS deals were built around lighting retrofits, chiller replacements, controls, and occasionally solar. The mix has shifted. In cities with binding building performance standards, the emissions math of a project is now the design constraint, and no single measure moves that number the way switching a building off a gas-fired boiler onto electric heat pumps does. That’s why capital-project conversations that used to sprawl across a dozen possible measures increasingly land on heat-pump conversion as the cornerstone measure, with the other EaaS-eligible upgrades layered around it.

The Local Law 97 math. New York City’s Local Law 97 caps carbon emissions for buildings over 25,000 square feet. Buildings that exceed their limit face civil penalties of up to $268 per metric ton of CO₂-equivalent over the annual cap, plus $0.50 per square foot per month for failing to file a required emissions report (NYC Department of Buildings, Local Law 97 Contractor Action Summit). Final rules issued in December 2023 introduced a beneficial electrification credit (BE Credit) that applies a negative emissions coefficient to heat-pump conversions, with double credit for early movers who install by 2027 (Urban Green Council). The design of the credit is deliberate: it makes heat pumps the highest-leverage compliance move for existing multifamily and commercial buildings.

A modeled example. Urban Green Council’s worked example of a 100,000-square-foot multifamily building with a gas boiler shows the same building exceeding its 2030 emissions cap by 62%, generating a potential annual penalty of about $55,000 during 2030–2034. Replacing just 15% of the building’s fossil-fuel heating load with heat pumps drops the potential annual penalty from roughly $40,000 (without the BE Credit) to about $6,000 (with the BE Credit) — a nine-in-ten reduction driven almost entirely by one measure (Urban Green Council).

A real building. The 110-unit, 13-story 420 Beekman Hill co-op in Manhattan replaced its Con Edison district-steam heating and absorption chillers with 13 electric heat pumps (10 rooftop and 3 basement units), cutting expected energy use by 60% and greenhouse-gas emissions by 76%. Without the retrofit, the co-op was projected to face roughly $30,000 per year in Local Law 97 penalties during 2030–2034, rising to nearly $90,000 per year by 2040; the completed retrofit lets the building avoid triggering penalties through 2049. The $2.9 million project was reduced by about one-third through NYSERDA ($154,000) and Con Edison Clean Heat Program ($1 million) incentives, with the remainder financed via a loan the co-op is repaying over three years (Canary Media). The Building Decarbonization Coalition’s Ted Tiffany called getting a New York multifamily building off steam heat “the most challenging transition” in the current retrofit landscape (Canary Media).

Why an EaaS structure fits. Redaptive’s own Local Law 97 resource page states that 65% of NYC buildings do not currently meet the 2030 CO₂ caps and positions its EaaS model — variable, performance-based billing with no capital expenditure and off-balance-sheet potential — as a way to “tackle building retrofits at little to no cost” and “avoid costly penalties” across all three Local Law 97 compliance periods (Redaptive on Local Law 97). For a co-op board, a REIT, or a nonprofit institution, the appeal is straightforward: the compliance move gets made without a capital call.

The same logic increasingly applies in Boston (BERDO 2.0), Washington D.C. (BEPS), and a growing list of other jurisdictions with building-performance standards. In each case the cornerstone technology in the resulting EaaS bundle is the one that moves the emissions number the most — and in cold-climate multifamily and commercial buildings, that’s almost always heat pumps.

3. A growing finance vehicle — and the shape of the growth

EaaS is not a niche category. Multiple industry forecasts published in 2024–2026 project the global market growing at a compound annual growth rate somewhere between 7.7% and 13.9%, depending on scope, base year, and methodology — a wide band that still puts EaaS solidly among the faster-growing segments of the energy and sustainability finance space. Six representative forecasts are shown below to illustrate where the range comes from.

The consensus band tightens to roughly 9%–12% once outliers at each end are set aside. The drivers cited most consistently across these forecasts are decarbonization mandates, corporate net-zero commitments, the shift of capital-intensive equipment onto specialist balance sheets, and the growing appeal of off-balance-sheet operating-expense treatment for building energy assets.

4. Key differences among the prominent players

Names in the EaaS space often blur together in trade press — every provider claims a data-driven, performance-guaranteed, off-balance-sheet, decarbonizing offering. The differences that actually matter to a building owner are more mundane: what size of building or portfolio the provider will actually engage with, how much of the design-and-build work sits inside the provider vs. sub-contracted to a trade network, how much technology and metering the provider brings, and how central heat pumps are to their current playbook. Four names span most of the range.

A. Redaptive — large portfolios, proprietary metering, growing heat-pump emphasis

Redaptive, founded in 2015 and headquartered in Denver, targets large-scale enterprise and commercial-real-estate portfolios — one published case study covers 293 sites and 17 million square feet, with customers like T-Mobile in the mix (Redaptive case study; Commercial Observer). Its delivery is hybrid: Redaptive itself handles auditing, engineering, procurement, financing, and installation management, but partners with third parties for on-the-ground field execution (Business Council for Sustainable Energy). Its signature differentiator is Redaptive ONE, a proprietary IoT-metering platform — cellular-connected sub-meters for electricity, water, and gas feeding a data platform used for ESG and GRESB reporting, and for performance verification on EaaS contracts (Redaptive). Heat-pump emphasis is explicit and growing: Redaptive’s blog argues that cold-climate heat pumps “now make commercial HVAC electrification viable in places that once ruled [it] out,” noting that dual-fuel systems can electrify roughly 90% of a building’s heating load (Redaptive blog).

B. Budderfly — small-commercial franchises, in-house takeover, growing heat-pump specialization

Budderfly, based in Shelton, Connecticut, is the counter-example on scale: it targets small and medium-sized businesses and multi-site franchises — McDonald’s, Subway, fitness centers, retail, and assisted-living facilities — and reports more than 2,750 customer sites across 49 states (Budderfly; Latitude Media). Its delivery model is unusually deep for small commercial: Budderfly typically becomes the “utility of record” for the customer, investing its own capital in HVAC, refrigeration, and lighting infrastructure and running installation and maintenance in-house rather than through a contractor pass-through (NAESCO member spotlight). Technology is significant — IoT sensors, smart controls, and AI-based savings optimization, integrated with more than 400 utility company billing systems (SoftServe / Budderfly). Heat-pump emphasis is a stated priority: Budderfly is a manufacturing partner in the DOE’s Commercial Building Heat Pump Accelerator (Facilities Dive) and has developed its own all-electric “Ultra High Performance” HVAC system using Fujitsu VRF heat-pump technology (Businesswire).

C. Johnson Controls (OpenBlue Buildings-as-a-Service) — full EPC, deep tech stack, explicit heat-pump manufacturer

Johnson Controls sits at the “full stack” end of the market: an equipment manufacturer that also finances and operates as-a-service contracts, with in-house engineering-procurement-construction rather than a trade-network model. Its OpenBlue Buildings-as-a-Service offering is positioned for large and complex portfolios — schools, campuses, data centers, healthcare facilities, and industrial buildings — backed by capital partners including Apollo Global Management (Johnson Controls / Apollo). The technology layer is deep: OpenBlue is an AI-powered building operating system with 24/7 monitoring, fault detection, and real-time dashboards (OpenBlue). Heat-pump emphasis is quantified and central: Johnson Controls reported that in 2025 its commercial and industrial heat-pump portfolio cut customer annual heating costs by an estimated 32% while reducing greenhouse-gas emissions by an estimated 55% (1.6 million metric tons), and the company was recognized in New York’s Empire Technology Prize for low-carbon heating retrofits in tall commercial and multifamily buildings (Johnson Controls press release). Contract structures blend fixed-fee and outcome-based risk-sharing (Johnson Controls, OpenBlue Net Zero Buildings-as-a-Service).

D. Metrus Energy — the ESA original, trade-network delivery, general-efficiency focus

Metrus Energy, based in San Francisco, is the firm most associated with the original Efficiency Services Agreement (ESA), a pay-for-performance structure developed by founder Bob Hinkle in which Metrus funds 100% of project cost and the customer repays based on realized energy savings — functionally an operating expense rather than debt (Metrus Energy; DOE Better Buildings case study, BAE Systems). Metrus targets large commercial, industrial, and institutional facilities with total energy spend above $1 million and multi-site programmatic deals (ACEEE). Delivery relies on a trade network: Metrus is “the sponsor and equity provider,” with ESCOs and contractors executing design and installation under separate performance contracts (Trellis). The tech stack is more traditional than Redaptive’s or Budderfly’s — ongoing measurement and asset management rather than a proprietary IoT platform. Heat-pump emphasis is not a stated priority in the public case studies (which lean toward lighting, chillers, and water efficiency); a specific Metrus heat-pump project could not be confirmed from public materials.

Bottom line

Energy as a Service is a real, growing, and increasingly heat-pump-centric finance vehicle. The category is holistic by design — a well-scoped EaaS bundle can include lighting, controls, chillers, solar, storage, metering, and operations — but the emissions math of building performance standards, and Local Law 97 in particular, has moved heat-pump conversion to the center of most current EaaS deals in cold-climate multifamily and commercial buildings. The forecast range of roughly 7.7% to 13.9% CAGR across major industry publishers is wide, but the middle of that band (9%–12%) is where the consensus sits, and the drivers cited across the forecasts are the same forces this piece has walked through: decarbonization mandates, corporate net-zero commitments, and the appeal of getting a long-lived capital asset off the customer’s balance sheet.

Choosing among providers is less about slogans than about fit. A 40,000-square-foot franchise portfolio is a Budderfly conversation; a 17-million-square-foot enterprise real-estate portfolio is a Redaptive conversation; a campus or industrial complex with an in-house energy team may be a Johnson Controls conversation; a mid-market institutional program looking for a proven ESA template is a Metrus conversation. The one common thread across all four — and across most of the smaller regional players not covered here — is that heat pumps have moved from “one measure among many” to “the measure that makes the emissions number work.” That’s the shift worth watching, and it’s what will drive the next round of EaaS deal flow. A follow-on piece — call it EaaS Part II — will look at the smaller regional and specialty operators, contract-mechanics details (baselining, M&V, performance guarantees, credit stack), and how the model is starting to combine with tax-credit-transfer and Inflation Reduction Act monetization strategies.