I am trying to determine the best ventilation strategy for an airtight home in Climate Zone 5A that will be using radiant floor heat as its primary heating system. The house we have designed is a 3040sf ICF home – 1040sf basement, 2000sf main level. The home’s foundation and main level walls will be built entirely out of Quad-Lock ICF forms and will utilize Quad-Deck flooring for a main level concrete floor over the basement. We will have a truss built roof with R-50 blown in cellulose insulation in the attic.

In terms of the H.V.A.C. acronym, my current assumptions are as follow:

Heat – Provided by radiant heat in concrete slabs on both lower and main levels.

Ventilation – Probably going to need an ERV to add fresh air to the house while conditioning incoming fresh air and capturing moisture in outgoing air as necessary.

Air Conditioning – We will need to provide cooling for the warmer months so we will have an air handling unit with evaporative and condensing coil connected to ductwork providing cool conditioned air to various rooms throughout the house. 

Where I’m confused is whether the ductwork for an ERV and the Air Handling Unit are one of the same? I’m looking for a simple diagram to understand their relationship to one another but having a hard time finding anything. Everything seems to show an ERV and its ductwork belonging to itself and not coupled with a cooling system.

Please excuse me if what I’ve described is not accurate as I still have a lot to learn when it comes to the HVAC design of high performance homes.