Depending on the solar system, the home, and the homeowner’s desires for their system, various project installations may include different “adders.” Some adders are necessary for the solar system to be able to operate, while others are optional features a homeowner may prefer.

An example of an operational adder would be a roof constructed with tile or a particularly steep roof slope. Each of these may incur an additional cost to install the panels.

An example of an elected adder would be an optional battery system.

Important: Be sure to take note of potential adders from the very beginning of the sales process! Adders that are not identified until after funding has been secured could result in reduced sales commissions, out-of-pocket costs for the homeowner, or the need to revisit funding approval. All of this can increase the likelihood of contract cancelation.

Examples of common adders are outlined in the table below. Adders are market specific, and you should consult your sales support representative to ensure they are accurate for your area of focus. If an adder price is marked with an asterisk (*), the price will automatically be calculated in the app once it is selected. All other adders must be added manually by the salesperson in the app’s ITC adder line.




Small size system < 4kW

Adder accounts for fixed cost associated with system installation


Main Panel Upgrade

Potentially necessary in older homes or when home has 100 amp Main Service Panel and solar system is larger than 5 kW


Move Vent Pipe

Non-combustion vents only

$200 each

Metal roof

Corrugated or standing seam

$.10/ Watt*

Flat Tile roof

Cement & walkable tiles without breaking

$.10/ Watt*

Hard Spanish Tile

“S” shape

Cement & walkable without breaking

$.10/ Watt*

Soft Spanish Tile

“S” shape

Clay, ceramic, breakable

Custom Quote

Steep roof > 35°

Steeper than 45º may be disqualified

$.05/ Watt

Flat roof < 5º

Chemically bonded

$.10/ Watt

Ground Mount, Substructure

Trenching not included

$.50/ Watt*

Ground Mount Trenching, Conduit, and Wiring

Linear distance from array to service panel, avoiding obstructions

$10/ Linear Foot

Extended Inverter Warranty

Extension of the standard 10 year warranty

See Manufacturer Website

* When selected, the cost is added automatically in the app.

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