As Connecticut and western Massachusetts’s premier mechanical contracting firm for over 135 years, we specialize in the design, installation, and maintenance of mechanical HVAC, plumbing, and fire protection systems.



In 1882, Michael Joseph Daly founded a small mechanical contracting firm which used horse-drawn, wooden-wheeled trailers to deliver pipe and equipment to local customers.

Over a century later, we’ve added pipe fabrication and fire protection to our resume and are now industry leaders, employing the latest in Building Information Modeling (BIM), modular prefabrication methodology, and Integrated Project Delivery (IPD) construction methods.

What can we do for your building?

We are an authorized dealer of Fike Fire Solutions.


Decades of experience constructing and servicing the most complex systems has allowed MJ Daly to earn the trust of some of the most high-profile facilities in New England. With a leading edge approach to design and construction, MJ Daly provides a depth of expertise across a full range of system types.

Commercial Construction

  • HVAC & Refrigeration
  • Plumbing & Heating
  • Fire Protection
  • Pipe Fabrication

Industrial Construction

  • Process Piping (Clean/High Purity)
  • Power Piping
  • Underground Utilities

Environmental Construction

  • Wastewater
  • Clean Water


  • Design and Build
  • Plans/Specifications
  • Retro Commissioning
  • Energy LEED Audit and Consulting
  • System Installation Diagnostics
  • Building Automation & Controls

Maintenance & Service

HVAC, Plumbing, Fire Protection & Alarm

  • Testing & Balancing
  • Systems Repair & New Equipment Installation
  • 24 Hour Emergency Service
  • Preventative Maintenance Service Agreements
  • Remote Systems Monitoring
  • Re-Commissioning and Verification
  • Engineering Consultation
  • ENERGY STAR Compliance & Rebate Programs


3D Modeling & BIM

  • Systems are animated in 3D and available in the cloud
  • Drawings are reviewable in an instant
  • Identify issues before installation
  • Quick, effective multi-trade applications
  • Cost efficiencies are realized with labor savings

In-house Fabrication Material & Supply

  • Multiple facilities totaling nearly 100,000 sq. ft.
  • State-of-the-art cutting, bending and welding equipment
  • Complete solution – from conception to fabrication
  • Reduces field labor requirements
  • Jobsite delivery of fabricated work

Engineering & Design-Build

Advanced engineering services:

  • Resource conservation in design
  • 3D / BIM drawing capabilities
  • Forward thinking, state-of-the-art mechanical system design
  • Owner support and care through every project phase

Green & Sustainable Energy

Just a few of the sustainable building systems we offer insight on:

  • Geothermal Systems
  • Photovoltaic Power and Solar Heating
  • Gas Absorption Heating & Cooling Systems
  • Water Conservation
  • Energy Recovery



  • Our systems are designed in the most efficient manner
  • Industries leader in green, LEED technology
  • Several LEED certified professionals on staff
  • LEED certified professional engineering team in-house

Energy Star

  • Building ratings against Energy Star criteria to compare to similar businesses in the same market
  • Plan for design and retrofit of new Energy Star rated products & practices

Certifications & Licenses

  • Fully certified and licensed in the industry’s most prestigious and well-known organizations
  • We provide safe, sound and cost-effective solutions for our customers and our certifications and licenses prove it