Important: This feature is currently in Beta. Please give us your feedback through support@ekotrope.com
The Spray Foam Optimizer finds the least amount of spray foam a home needs to pass a target energy code. Pick a code, a spray foam product, and an infiltration value (or leave as unchanged). Ekotrope then tests spray foam in the walls, in the ceiling/roof, and in both. If spray foam enables the home to pass code, Ekotrope will report the how much spray foam is required to get there.
Reference the following descriptions for input-specific guidance:
| Target Energy Code | The energy code to optimize for. The optimizer will calculate how much spray foam is required to meet this code, if possible. |
| Spray Foam Product | The type of spray foam to use in the optimizer calculation. The optimizer will use the published R-values for this product to calculate how much is required to meet the target energy code. |
| Infiltration | The infiltration to be applied in the optimizer calculation. Spray foam can help achieve a tighter envelope. On average in Ekotrope, homes with spray foam have an ACH50 which is around 1.0 lower than homes without spray foam. |
Modeling assumptions and changes to the building design
Using Spray Foam in a building design can change what is possible in meaningful ways. For example, using spray foam often means you can move ducts into conditioned space.
The Spray Foam Optimizer makes a number of assumptions about how the building design will change as a result of using Spray Foam for insulation. These assumptions are included in the energy modeling when the Spray Foam Optimizer calculates how much spray foam is required to meet code.
Below is a summary of how the Spray Foam Optimizer changes the as-modeled house plan:
| Walls | The insulation in each wall's stud cavity is replaced with the spray foam product, installed as Grade I. Framing, sheathing, and drywall don't change. Foam depth is capped at each wall's own cavity depth (core depth for CMU). |
| Vented attics | The attic becomes a sealed attic. The ceiling area becomes the roof-deck area. The roof assembly becomes asphalt shingles + ½″ sheathing + 2×6 rafters (5.5″) with spray foam in the rafter cavity. Foam deeper than 5.5″ is added as a new continuous layer. |
| Infiltration volume | The sealed attic's volume is added: ceiling area × attic height ÷ 2, assuming a gable roof. |
| Ducts and equipment | Ducts and conditioning equipment in the vented attic, plus equipment with no location set, move into the conditioned attic. |
| Knee walls | Walls next to the former vented attic become adiabatic. |
| Sealed attics and vaulted ceilings | The existing assembly is kept. Foam fills the cavity first, and anything deeper is added as a continuous layer. |
| Insulation Thickness | Walls range between 1″ up to the cavity depth in ½″ steps. Ceilings/roofs range between 3″ to 24″ in ½″ steps. |
How the optimizer works
These are the steps that the Spray Foam Optimizer takes, in the order they happen:
| Check that passing the code is possible. | First, the home is modeled at maximum foam: walls filled to full cavity depth and 24″ at the ceiling. A home that fails even this is dropped. If no case passes, you get the message "This plan will not pass code with the highest insulation levels." |
| Search for optimal walls-only, and ceiling-only scenarios | For the walls-only case, and separately for the ceiling-only case, the optimizer finds the thinnest ½″ step where the code passing margin is zero or higher. |
| Walls and ceiling together | The optimizer finds the scenario with the lowest total foam volume which passes the target energy code. Volume is calculated based on the sprayed area, excluding framing, and the continuous layer on the roof deck. |
| Results | The results for each case are displayed. If there is no thickness for a case (walls-only, ceiling-only, or walls+ceiling) which passes the target energy code, no results are displayed for that case. |
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