Hillside Heating & Cooling is an award-winning, full-service heating, air conditioning, heating oil delivery, and commercial fuel company serving residential and commercial customers for over 73 years in New Castle County, DE, Cecil County, MD, and Southern Chester County, PA. Having earned over 3,000 certified 5-star reviews and testimonials, Hillside is committed to its mission, “keeping customers cool in the summer and warm in the winter while delivering customer service right.”