How are individual guestroom VTACs calculated?

The guest room HVAC units contain three energy end uses - heating, cooling and fans. Metering them together or individually will not give you the end uses you need. It will be very difficult and costly to do the necessary metering with these types of systems in this type of project.

Ultimately you would need to meter the VTAC's heating, cooling, and fan end uses for all of them. Yes potentially very costly.

Marcus,
Following up on this question in the context of a high-rise multifamily building. In our case, the building will likely have one master utility meter and then submeter and bill tenants based on usage. Do you know if the submeters that are used in this context have the ability to further submeter end uses in each unit to a BAS or other system? Or is that why you feel that it's cost prohibitive?

Thanks,
Josh

Hey Josh,

I suppose you could find some submetering equipment that could separate energy end uses. In my experience to do so would be very expensive. Basically you would need to separate the electrical circuits by end use. Depending on certain factors the heating, cooling, fans, DHW and plug loads are probably over 10% for the building as a whole. Maybe pumping, maybe exterior lighting, etc. Each needs to be separately metered and then added together for each unit as well as any common spaces. Sounds like a lot of equipment to me even if most of it is inside the panel boxes.

Yeah. That's what we thought too. But it essentially means that the credit is more or less of limits for MF projects. That seems too bad.

Thanks for the reply. V helpful.