O3

What O3 does

O3 is an Estonian MEP (Mechanical, Electrical, Plumbing) engineering design consultancy operating from Tallinn with a secondary presence in Kuressaare. Founded circa 2013, the firm provides BIM-based technical systems design, external network engineering, project management, and energy efficiency consulting under Estonian construction standard EVS 932:2017, covering half (15 of 30) of the project parts in that standard. Its core technology stack is BIM for design coordination and visualization, supplemented by IDA-ICE for dynamic energy simulation, daylight factor analysis, and overheating compliance checks. The firm has issued over 280 energy performance certificates (energiamärgis) since 2015 and delivers specialized energy efficiency services including ETA/KEK calculations, summer room temperature (SRT) control, and renewable energy solution design.

O3 operates as a B2B professional services firm selling project-based engineering design and consulting to property developers, architectural firms, construction companies, and public sector entities in Estonia. Named customers span healthcare (Confido Healthcare Group, Viljandi Haigla, Kohtla-Järve Haigla, Jüri Tervisekeskus), retail (Rimi Eesti Food AS, LIDL Eesti), real estate development (Merko Ehitus, Bonava Eesti, Neli Nurka OÜ, 1Partner Ehitus), hospitality (Restor AS), architecture (Eesti Ehitusprojekt OÜ), and government (Vigala Vallavalitsus). Revenue is generated through per-project fees; pricing is not publicly disclosed and is handled via [email protected] inquiries. Customer acquisition is relationship-driven, with no disclosed marketing spend or formal sales motion beyond a bilingual (Estonian/English) website and direct contacts.

The firm runs on a lean 1–10 employee base led by project managers Mihkel Hiielaid and Mats Viisileht, with department-specific contacts for HVAC/energy efficiency, water/sewerage, and electrical disciplines. O3 is privately held with no disclosed funding rounds, parent company, or M&A activity, and operates exclusively within Estonia with no stated international expansion plans. Its operating posture is that of a specialized local engineering consultancy whose value proposition rests on regulatory compliance expertise, BIM-integrated MEP design, and head-design responsibility across technical systems for the Estonian built environment.

Name

O3

Legal name

O3

Website

https://o3.ee

Company type

Private

Founded year

2013

Operating status

Operating

Headcount range

11–50 employees

Short description

O3 is an Estonian MEP engineering consultancy founded circa 2013 that provides BIM-based mechanical, electrical, plumbing, and external network design plus energy efficiency consulting to property developers, architectural firms, construction companies, and public sector clients across Estonia.

Ownership category

akta.pro rank

Product category

MEP Engineering Design Services

NAICS

Engineering Services (54133), Engineering Services (541330)

SIC

Services-Engineering Services (8711)

akta.pro primary industry

Building Management & Facility Control Systems (BMS/BAS, Power Monitoring, EPMS) (EUAEAFAJ)

akta.pro secondary industry

Renewable Energy Asset O&M (Wind, Solar, Hydro, Geothermal) (EUAEAGAB)

Keywords

• MEP engineering design
• BIM modeling services
• Building energy efficiency
• Energy performance certification
• External network design

Headquarters

HQ city

Tallinn

HQ country

Estonia

HQ region

Europe

Offices1 record

Markets served

GTM type

B2B

Offering type

Services

Cost components

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

Revenue model

1. MEP Engineering Design Services: Project-based fees for technical systems design services including heating, ventilation, cooling, water/sewerage, electrical installations, telecommunications, automation, and fire safety systems. Services offered across all project phases from preliminary design through execution drawings.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels1 record

Core offering

O3 is an Estonian engineering consultancy that delivers complete Mechanical, Electrical, and Plumbing (MEP) systems design and external network engineering for building projects. The firm works in BIM (Building Information Modeling) per Estonian standard EVS 932:2017, covering 15 of 30 project parts across both facilities and buildings. It also offers energy efficiency consulting, energy performance certification, dynamic energy simulation, daylight analysis, and renewable energy solutions.

Product overview

O3 is an MEP (Mechanical, Electrical, Plumbing) engineering design company offering complete technical systems solutions for buildings and facilities. The company operates as a unified service portfolio organized around core design disciplines including MEP Systems Design, BIM/3D Modeling, External Network Design, Project Management, and specialized Energy Efficiency Services. Energy Efficiency Services encompass multiple sub-services including Energy Performance Certificates, Summer Overheating Analysis, Daylight Factor Analysis, ETA/KEK Calculations, and Renewable Energy Solutions. All design work is implemented in BIM (Building Information Modeling) system per Estonian construction standard EVS 932:2017, covering half of the 30 project parts in building projects. The company has completed over 280 energy certificates and numerous projects across residential, commercial, healthcare, educational, and industrial building types.

Differentiator

Problem solved

Functional benefit

Quantifiable outcome

• Over 280 energy performance certificates produced for existing and designed buildings since 2015

Named customers15 records

Segments4 records

Ideal customer profiles7 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature5 records

Scale indicators1 record

Recent moves5 records

Expansion highlights4 records

Broad incumbents

• Arup: Global engineering consultancy whose buildings practice covers MEP, sustainability, and energy modeling - the same disciplines at the core of O3's offering, but at substantially larger scale and global footprint.
• WSP: Global engineering professional services firm with property and buildings capability covering MEP, energy, and sustainability consulting - overlapping with O3 across much of its service portfolio.

Direct peers

• SWECO: Largest Nordic engineering consultancy; SWECO Eesti competes directly with O3 for Estonian MEP/BIM design mandates for property developers, architects, and public-sector clients.
• AFRY (formerly ÅF): Nordic engineering and design consultancy with Baltic presence building and infrastructure teams that overlap directly with O3's MEP, BIM, and energy-simulation work.
• Granlund: Finnish MEP engineering firm recognized for BIM-based building-services design and energy simulation; operates in a very similar niche and competes for the same type of mandates in the Nordics/Baltics.
• Ramboll: Global engineering consultancy with a Tallinn office; Ramboll Eesti pursues the same building-services and energy-efficiency design briefs as O3 across healthcare, commercial, and residential projects.

Others

• Equa Simulation (IDA Indoor Climate and Energy): Developer of the IDA-ICE simulation software that O3 uses for dynamic energy, daylight, and overheating analysis; adjacent ecosystem participant rather than a direct competitor.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat3 records

Key risks5 records

Key highlights6 records

Customer concentration

Revenue estimate

Valuation estimate

Number of profiles

Profiles2 records

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 O3