How to determine what type of HVAC system you're looking at:
- Is there any equipment on the roof, exterior walls, or around the building? Count the equipment you see.
- Count the thermostats inside the building. The number of thermostats represents the number of HVAC zones in the building.
- Compare the number of thermostats to how many pieces of equipment you found.
- You have a centralized system if the number of thermostats is larger than the count of equipment you found.
- If the number of thermostats equals the count of equipment you found, the system is a unitary system.
- If you've determined the HVAC system is a unitary system, you now need to determine if it's a package system or a split system. A package system is located completely outside the building, while a split system is divided between the outside and inside of the building (typically a condenser located outside and a fan coil inside).
- You have a package system if you see ducts connecting the HVAC equipment and the building because package systems use air to move heat.
- You have a split system if you see no ducts, but you do see pipes carrying refrigerant into the building. There will typically be two pipes, one that is insulated.
Ways to gather the data you need when out in the field.
- Look at a thermostat or the controls system to see how long the system runs at one time.
- Place a logger on pieces of the HVAC equipment, motors or fans.
- Ask the building manager if they have a general pattern of occupancy for the building.
Nameplates
Taking photos of nameplates and notes in the field is especially important because you'll refer back to these later on in the audit process. Be sure to take clear, high resolution photos to ensure you can record the specifications.
Items to make note of:
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Manufacturer
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Model #
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Serial #
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Year Built
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Number of Zones Served by Unit
hint: check the number of thermostats -
Unit Type
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Compressor Data
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Condenser Fan Data
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Supply Fan Data
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Supply Fan Motor Data
Links to learn more: