How a measure gets flagged

The CET builds a short list of three fuel-substitution fuel types:

AllElec-New, FuelSub-ToElec and FuelSub-ToGas.

Any measure whose FuelID is on that list is a fuel substitution measure. All other measures are handled the normal way.

Cost effectiveness calculation differences

1. Avoided-cost benefits (ElecBen, GasBen) and supply costs (ElecSupplyCost, GasSupplyCost)

Normal measures save energy, so the avoided-cost calculation always produces a benefit. A fuel substitution measure can go both ways: it saves one fuel and uses more of the other.

For each fuel, the CET calculates the same quantity (units × net-to-gross × energy change × avoided cost) and then sorts it by sign:

In plain terms, for a gas furnace swapped for a heat pump, the gas saved is a benefit and the extra electricity is a cost. A normal measure only has the benefit side. The same sorting is applied to each of the avoided-cost versions the procedure tracks, and to both the net and gross figures. That is 12 benefit fields and 12 matching supply-cost fields.

2. TRC, PAC and the total system benefit

The supply costs from step 1 are then used in two ways:

• Total system benefit is the benefits minus the supply costs.

• TRC and PAC costs include the supply costs as extra cost in the ratio denominator.

For a normal measure, the supply costs are zero, so these totals work out the same as before.

Bill savings (RIM)

A normal measure’s bill change always goes into BillReduc. A fuel substitution measure’s negative bill change goes into BillIncr, which then shows up on the benefit side of the RIM ratio.

Excess incentives (costs)

Excess incentives are rebates, incentives and direct-install costs minus the measure’s gross cost.

• A normal measure only counts this when it is positive. If the program paid out less than the measure cost, it is treated as zero.

• A fuel substitution measure counts it even when negative. The same applies to Codes & Standards measures, and to measures where incentives exceed the cost.