W.H. Demmons is a leading design-build-maintain engineering firm focused on reducing your energy costs through proven innovative engineering, design, and installation solutions. Our history began in 1914, with the creation of Demmons Roofing, which offered quality commercial roofing services to clients through the Northeast. Exactly eighty years later, in 1994, the company merged with Maine Air Conditioning, which was founded in 1974, to expand the company into commercial HVAC solutions.

With the acquisition of Maine Air Conditioning, W.H. Demmons became a global leader in the HVAC innovation and technology industry, after having completed its first geothermal building in the 1990s.

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Our Team Report

Douglas began his career in 1976, when he joined the Carrier Corporation. Over the next 40 years, he went on to work for companies around the world, from Galson & Galson Consulting Engineers to Munters Cargocaire. In 1986, he became a partner at W.H. Demmons, Inc., and eventually moved into the position of owner and president.

Services Report

Rather than just design HVAC systems, W.H. Demmons is a full-service design-build-maintain company. We work with our clients to create a customized HVAC solution, which we can then properly install. To ensure the system is operating at up-to-the-moment maximum efficiency, we will maintain the HVAC unit(s) using cutting-edge control systems.

Safety Report

It's easy to forget about the air we breathe. It's a subconscious act: inhale, hold, exhale; repeat. But the moment air quality deteriorates for any reason - excessive particles, chemical fumes, biting cold or burning heat - breathing becomes a safety concern. It can even become deadly. It's the driving force behind every project, because we understand that we create more than cost-effective solutions - we're creating life-sustaining environments.Humidity, airflow, temperature regulation, these factors must be carefully manipulated, otherwise one's safety is at risk, and our professional staff has the experience and expertise to ensure every project meets and exceeds safety standards.

Careers Report

W.H. Demmons is looking for experienced construction and support staff who share "can-do" work ethic and who will thrive in our fast-paced, demanding culture. Our firm is characterized by honesty, integrity and a commitment to getting the job done. If you think you can help us exceed our client expectations please respond to our Human Resource Director.

Lisa Durost

Jan 22, 2022

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This company allows their drivers who are not safe to be on the roads. They also are a very poor managed company who don't have a lot of good things to say about their employees. I worked there as a service coordinator and never got anything good said to me. Their is no privacy between managers and employees and everyone knows your business. It's pretty sad because the owner is great and the sheet metal manager is amazing but the HVAC side is terrible as far as management goes.

Bob Severance

Mar 12, 2021

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Critical: Professionalism, Punctuality While their HVAC services are excellent, their roofing group is not to be trusted. Promises made and not kept. Time and appointment promises made and not met. Do not rely on these roofers for anything except for unprofessional management and client service. If you count on them, you will not be counting on your roof being done.

Blitz Aurora

May 15, 2020

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Never hired or been here, but I've come across the contractors on multiple occasions and every single one of them have been helpful to me. Yall sure know how to pick em.

Andrew P.

Feb 06, 2019

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Trustworthy, professional, and they give you options to help you make the best decision for your company.