Pat Split comment 6/5/20: Residential slab-on-grade hydronic heating systems rarely use tubing installed within the structural slab anymore. The tubing is installed above the slab, either in a topping slab or some sort of panelized system. Either way, these systems have a layer of insulation completely separating the tubing from the structural slab. This cannot be modeled. The closest option is to model a 4-foot strip projecting in from the edges of the slab. This exaggerates the heat loss to the slab and requires additional unnecessary efficiency measures. This should be corrected so that these installations will be more accurately modeled. A problem which sometimes occurs is the CF1-R indicates that these installations require slab-edge insulation. If a building inspector goes looking for this, it will not be found. It is difficult to explain that this is OK.
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Pat Split comment 6/5/20: Residential slab-on-grade hydronic heating systems rarely use tubing installed within the structural slab anymore. The tubing is installed above the slab, either in a topping slab or some sort of panelized system. Either way, these systems have a layer of insulation completely separating the tubing from the structural slab. This cannot be modeled. The closest option is to model a 4-foot strip projecting in from the edges of the slab. This exaggerates the heat loss to the slab and requires additional unnecessary efficiency measures. This should be corrected so that these installations will be more accurately modeled. A problem which sometimes occurs is the CF1-R indicates that these installations require slab-edge insulation. If a building inspector goes looking for this, it will not be found. It is difficult to explain that this is OK.