Older systems can become less efficient, costing you more and more money in repairs and in heating bills, not to mention the environmental impact. Newer units are more energy efficient and come equipped with better filtration systems, so recirculating air is cleaner. You may want to move a system to repurpose the space in your attic, basement, or garage where the unit is housed. All heating systems have pros and cons. An HVAC professional can help you decide what size, number of systems and location will serve your needs best.