49+
Years Of Experience
About Us
Our Story & History
Founded in 1977, William G. Day Company began as a small, local plumbing and HVAC service in Wilmington, Delaware. After years of dedication, Brian and JoAnne Marcocci, who worked for the original owners, transitioned into ownership in 2023-continuing the company's long-standing tradition of integrity and quality.
Milestone progression: Over the decades, WGD grew into a full-service residential and commercial plumbing and HVAC company, became a Certified Factory Authorized Carrier Dealer (CFAD), and earned an A+ rating from the BBB.
Challenges & growth: As HVAC technology, industry regulations and customer needs have evolved, the company has continued to invest in training and certifications to provide dependable, high-quality service.
Evolution: Today, WGD provides complete HVAC and plumbing solutions, including air conditioning, gas furnaces, heat pumps, indoor air quality services and comprehensive plumbing services.
Founding story: Built on trust, quality workmanship and strong community relationships, the company continues to provide dependable, customer-focused service.
Our Team
Owners & leadership: Now led by Brian and JoAnne Marcocci, whose journey from employees to owners shows their dedication and deep understanding of the business.
- Family & staff: Two of their sons work in the company alongside a talented team of 14 other experienced staff members-bringing together years of hands-on expertise and customer-first service.
- Culture & motivation: The team prides itself on honesty, respect, and quality work-not high-pressure sales-creating a welcoming, professional experience for every customer.
- Trust & credibility: Nearly five decades of service, CFAD certification, and an A+ BBB rating underscore the company's commitment to doing the right thing, every time.
Our Impact & Offerings
Who we serve: Homeowners and commercial clients across Delaware, Eastern Maryland, and Southeastern Pennsylvania looking for reliable, long-term HVAC and plumbing solutions.
- Services: - HVAC installation, repair, and maintenance (including furnaces, AC, and heat pumps) - Plumbing repairs, water heater services, and Indoor air quality solutions.
- Customer benefits: - Free estimates for installation of new equipment - Emergency service when you need it - Flexible financing and clear, pressure-free advice
- Approach: Combining certified technical expertise with a commitment to honesty and respect-ensuring comfort, efficiency, and peace of mind for every client.
