For the best furnace repair in Frederick, MD, choose Markool Heating & Cooling, a professional HVAC contractor providing next-level HVAC service performed by NATE-Certified techs. Frederick nights can get quite cold, and it’s not time to take a gamble on the quality of your furnace or heat pump repair. When you choose Markool Heating & Cooling, you know that you will get a job completed the first time correctly, with top-of-the-line parts to last a long time. We take our time to find the full extent of your furnace or heat pump problem and come prepared with every tool and part we could need so we’re able to get it running again quickly. We strive to save you time and money. Call us today for your reliable furnace repair!