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Ventilation and Cooling for An Airtight Home With Radiant Heat

megapointe | Posted in General Questions on

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.

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  1. paul_wiedefeld | | #1

    Radiant floors in well insulated and air sealed homes don't provide all that much in terms of comfort and unless you're using a heat pump, it will not be green. When used in slabs, they're hard to control due to the time it takes to warm/cool them. They're also extremely expensive for a redundant and limited system.

    Since you're installing ductwork, an air-to-air heat pump can easily handle both heating and cooling.

  2. megapointe | | #2

    We are planning a geothermal system for our radiant loop. Do you have any suggestions as to what cooling and ventilation strategies I could use in tandem with this heating system for the cooling months?

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