There are several different types of HVAC systems. Picking the one that best suits your space is just as important as making sure that it functions properly. These few simple questions should make the decision much easier.
How big is my space?
This is an extremely important factor to consider if your space is particularly large or particularly small. If the area is very large, you might consider a high-powered system with elaborate ventilation and ducting to properly disperse the heat or air conditioning. However, a split system is another great option for buildings with a lot of space—especially if it also has many enclosed rooms. A split system funnels heat and air conditioning to individual rooms rather than dispersing it homogeneously throughout the building, and therefore can be the far more efficient way to go for a spacious building.
As for small spaces, packaged HVAC units are usually your best bet. As the name implies, a packaged unit keeps most of the components in one compact package, and therefore are easier to find a place for in a more cramped area.
How old is my space?
Older buildings sometimes will not have the structure to accommodate standard components of an HVAC system, such as the ducting. In such cases, a ductless system is probably the best solution. Ductless systems— rather than pulling the air from one place to another through ducts— funnel air directly into the space.
What is the climate like in my area?
If your building is situated in a climate that can reach extremely low temperatures, your heat pump might be rendered far less effective when the temperature drops below freezing. A hybrid heating system can solve that problem. Hybrid heating systems utilize the usually more efficient heat pump until the temperature drops below a certain level. When that happens, the system kicks on the furnace—which is not similarly affected by low temperatures.