C4SB - Coalition for Smarter Buildings

What C4SB - Coalition for Smarter Buildings does

The Coalition for Smarter Buildings Foundation (C4SB) is a 501(c)-style non-profit foundation operating as a project series of The Linux Foundation, headquartered in Kansas City, MO, with active members across North America and Europe. Founded in 2021, the organization convenes 12 working and interest groups to develop open standards and open source resources for the digital transformation of buildings, spanning the full lifecycle from planning and design through construction, operations, tenant experience, and real estate transactions.

C4SB's technical portfolio centers on the Interoperable Building Box (IBB) cloud-native on-premises data exchange architecture, the Semantic Buildings project that integrates open semantic models (Project Haystack, Brick Schema, ASHRAE 223P, REC, AAS, BIM, SAREF, BOT), the Division 25 specification framework, the Managed BACnet / BACnet Cloud Collective, the Asset Leadership Standard for executive-level coordination of smart assets, TxO (Total X of Ownership) KPIs, Digital Building Profiles, Grid Interactive Buildings, and UDMI. In 2025 the organization restructured under the Linux Foundation, absorbed LonWorks International's LonMark project, and in 2026 launched an NIST-led multi-year building cybersecurity working group.

The foundation is funded entirely through membership dues across four tiers: Strategic Members ($100K-$120K annually with a Governing Board seat and 2-year commitment), General Company Members ($5K-$70K annually based on employee headcount, LF-discounted), free Associate Membership for non-profits, NGOs, academia and government, and free Individual Participation. Customers and contributors span building owners, operators, proptech startups and venture investors, vendors, governments and non-profits, real estate professionals, and building occupants.

Name

C4SB - Coalition for Smarter Buildings

Legal name

Coalition for Smarter Buildings Foundation

Website

https://c4sb.org

Company type

Private

Founded year

2021

Operating status

Operating

Headcount range

1–10 employees

Short description

C4SB Foundation is a Linux Foundation project series that convenes 12 working groups to develop open standards and open source resources (IBB architecture, semantic models, Division 25, Managed BACnet) for the digital transformation of buildings. It is funded by membership dues and serves building owners, operators, vendors, proptech startups, and governments globally.

Ownership category

akta.pro rank

Product category

Smart Building Open Standards

NAICS

Grantmaking Foundations (813211), Grantmaking and Giving Services (81321)

SIC

Services-Computer Programming Services (7371)

akta.pro industry

PRIMARYBPAGAKAA

Private Foundations

Business & Public Services/Nonprofit, NGO & Social Services/Philanthropy, Foundations & Grantmaking

SECONDARYBPAGAKAM

Environmental & Climate Grantmaking Foundations

Business & Public Services/Nonprofit, NGO & Social Services/Philanthropy, Foundations & Grantmaking

SECONDARYBPAGAKAH

International Grantmaking & Development Foundations

Business & Public Services/Nonprofit, NGO & Social Services/Philanthropy, Foundations & Grantmaking

Keywords

• Smart building standards
• Building automation interoperability
• Open source building frameworks
• Building digital transformation
• Smart building community

Headquarters

HQ city

Washington

HQ country

United States

HQ region

North America

Offices1 record

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Technology or R&D, Marketing or Sales, Infrastructure

Revenue model

1. Strategic Membership: Strategic Members commit major support to C4SB's work with annual fees. They receive higher visibility on C4SB website and marketing materials, and a seat on the C4SB Governing Board which decides how to allocate C4SB funds. Requires an initial 2-year commitment.
2. General Company Membership: Membership available for companies giving commitment to open-source and Linux Foundation visibility. Benefits include visibility on C4SB and company websites and marketing materials. Priced by employee headcount with tiered annual fees ranging from $5,000 to $70,000 for non-LF members.
3. Associate Membership: Free membership tier for non-profits, NGOs, academic institutions, government research institutions, and pre-approved open source projects.
4. Individual Participation: Free individual membership with no fee. Individuals can join and contribute to any and all C4SB interest groups, working groups, events and activities. Some events, trainings or other activities may have a fee.

Pricing tiers

Go-to-market motion1 record

Distribution channels3 records

Marketing channels5 records

Core offering

C4SB Foundation is a member-funded non-profit organization that develops open standards and open source resources for the digital transformation of buildings. It convenes working groups that produce semantic data models, interoperability architectures, and management frameworks (e.g., Semantic Buildings, Interoperable Building Box, Asset Leadership Standard, Managed BACnet, Division 25) to enable cloud-native, vendor-neutral data exchange across building systems. The Foundation operates as a project series of The Linux Foundation and offers tiered membership programs for building owners, operators, vendors, and contributors.

Product overview

The Coalition for Smarter Buildings Foundation (C4SB) is a Linux Foundation project series that operates as a community-driven organization developing open standards and open source resources for the digital transformation of buildings. Rather than a single commercial product, C4SB offers a portfolio of interconnected projects including Semantic Buildings (semantic model integration), Asset Leadership Standard (management framework), Interoperable Building Box/IBB (cloud-native data architecture), Managed BACnet (BACnet cloud deployment), Div2525 (specification framework), TxO (ownership KPIs), Digital Building Profiles, and related standards. These projects work together to enable interoperability, data exchange, and open solutions across building systems throughout their lifecycle.

Differentiator

Problem solved

Functional benefit

Products and services

• Strategic Membership
• General Company Membership
• Associate Membership
• Individual Participation

Segments7 records

Ideal customer profiles3 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature6 records

Partnerships

18 partnerships are on record, tiered core and supporting.

• The Linux FoundationcoreStrategic or Co-development PartnerIn February 2025, Linux Foundation announced intent to form the C4SB Foundation as a project series of The Linux Foundation. This major inflection point positions open building standards alongside mainstream digital infrastructure. Linux Foundation provides open-source governance, collaboration infrastructure, and global distribution for C4SB initiatives.
• CimetricscoreStrategic or Co-development PartnerInitial supporting organization for C4SB Foundation. Cimetrics, a founding member, is volunteering to chair and lead the Managed BACnet (BACnet Cloud Collective) working group addressing BACnet deployment in cloud-native buildings.
• Climatec (a division of Bosch)supportingStrategic or Co-development PartnerInitial supporting organization for C4SB Foundation bringing building automation expertise from Bosch division.
• CTI AlliancesupportingStrategic or Co-development PartnerInitial supporting organization for C4SB Foundation providing industry alliance expertise.
• Digital Master PlanningsupportingStrategic or Co-development PartnerInitial supporting organization for C4SB Foundation. David Wilts serves as moderator of the Digital Building Profiles working group.
• Engenuity SystemssupportingStrategic or Co-development PartnerInitial supporting organization for C4SB Foundation contributing engineering systems expertise.
• facil.aisupportingStrategic or Co-development PartnerInitial supporting organization for C4SB Foundation providing AI facilitation expertise.
• OnumasupportingStrategic or Co-development PartnerInitial supporting organization for C4SB Foundation contributing building design systems expertise.
• PadisupportingStrategic or Co-development PartnerInitial supporting organization for C4SB Foundation. Contact for Managed BACnet working group inquiries.
• SkyCentricssupportingStrategic or Co-development PartnerInitial supporting organization for C4SB Foundation contributing energy management expertise.
• VerdicitysupportingStrategic or Co-development PartnerInitial supporting organization for C4SB Foundation providing sustainability and building intelligence expertise.
• We Write CodesupportingStrategic or Co-development PartnerInitial supporting organization for C4SB Foundation contributing software development expertise.
• Asset Leadership NetworkcoreStrategic or Co-development PartnerInitial supporting organization for C4SB Foundation. Mike Bordenaro serves as Committee Moderator for Asset Leadership Standards, Jim Dieter as Committee Chair, and Nick Knoke as GitHub leader for the working group.
• Building Intelligence Group (BIG)supportingStrategic or Co-development PartnerInitial supporting organization for C4SB Foundation contributing building intelligence expertise.
• LonMark InternationalcoreStrategic or Co-development PartnerInitial supporting organization for C4SB Foundation. The LonMark project is merging the LonWorks International organization into the C4SB project series of The Linux Foundation.
• NIST (National Institute of Standards and Technology)coreStrategic or Co-development PartnerNIST launched a multi-year project to strengthen cybersecurity of building systems (HVAC, security, lighting, elevators) working within C4SB under the Linux Foundation. NIST will establish a Cybersecurity Working Group and host an ASHRAE Workshop session at the February 2026 winter conference. Initiative uses NIST Cybersecurity Framework, NIST Risk Management Framework, DOE C2M2, FEMP Framework, and ISA/IEC 62443.
• ASHRAEsupportingTechnology or IntegrationThe Managed BACnet working group is establishing permission to use the BACnet trademark from ASHRAE. NIST initiative includes hosting an ASHRAE Workshop session at the February 2026 winter conference.
• BACnet InternationalsupportingTechnology or IntegrationManaged BACnet working group is establishing liaison with BACnet International trade group for coordination on BACnet standards.

Scale indicators3 records

Recent moves8 records

Expansion highlights6 records

Direct peers

• LonMark International: Standards organization for LonWorks-based building automation, currently merging into C4SB's project series under The Linux Foundation — historically a peer and now a lineage predecessor.
• Brick Schema Consortium: Open metadata schema for buildings that C4SB lists among the semantic models being integrated, making it a directly adjacent (and potentially merger-eligible) standards effort.
• LF Energy: Sibling Linux Foundation project series for power-grid and energy-software open source — the natural counterpart for C4SB's Grid Interactive Buildings work and a coordination peer inside LF.
• BACnet International: Trade group promoting the BACnet building-automation protocol, with which C4SB's Managed BACnet working group is establishing formal liaison — making it a direct peer and coordination counterparty.
• Project Haystack: Open-source community developing semantic data tags for building equipment — a foundational community that C4SB's Semantic Buildings project explicitly aims to harmonize alongside.
• Real Estate Standards Organization (RESO): Open-standards organization for real-estate data interchange — a comparable community-led, member-funded body operating in the adjacent real-estate lifecycle domain C4SB targets.

Broad incumbents

• ASHRAE: Dominant building-systems standards body (including the BACnet standard and 223P semantic model) whose trademarks and specifications C4SB depends on, making it a powerful incumbent peer/partner.

Emerging players

• Open Connectivity Foundation (OCF): IoT interoperability standards body whose device-metadata work overlaps with C4SB's UDMI and IBB edge efforts, particularly across smart-building device connectivity.

Others

• Open Geospatial Consortium (OGC): Standards consortium for geospatial and location interoperability whose domain overlaps with digital-twin and building-context workstreams in C4SB's Semantic Buildings and Digital Twins projects.
• Eclipse Foundation (IoT Working Groups): Open-source foundation housing IoT and digital-twin projects (e.g., Eclipse IoT, ditto) — an alternative open-governance venue for building interoperability projects that overlap with C4SB's portfolio.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks7 records

Key highlights7 records

Customer concentration

• Xtwitter.com/C4SB_org

Revenue estimate

Valuation estimate

Number of profiles

Profiles1 record

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about C4SB - Coalition for Smarter Buildings