Does anyone know what the heat output is for the EX3400 & EX2200-C? I can not find this information anywhere.
I assume you are trying to measure an AC load. If so, you can use the equipment watts rating and convert to BTU load using the standard formula
usually your local Juniper Partner should be able to get hold of this information. There is a document provided to Juniper and Partner SE's with precise numbers for wiring closet switches with different traffic and PoE load.
I'm not allowed to give out these numbers in a public forum - so you need to go via your local partner.