What Is Change Order? Definition & Guide

Key Takeaways

A change order is a formal contract modification that alters the original scope, cost, or schedule of a solar installation — it requires written documentation and approval from both the contractor and the customer before work proceeds
Common triggers include unexpected roof damage, structural deficiencies, customer-requested upgrades (battery storage, additional panels), equipment supply chain issues requiring substitutions, and AHJ code compliance requirements discovered during permitting or inspection
The average residential solar change order adds $1,500–$4,000 to project cost and extends the timeline by 1–3 weeks, though AHJ-required changes can push delays to 4–6 weeks when re-engineering and resubmission are involved
Proper documentation must include the original contract reference, a detailed description of the change, itemized cost impact, revised timeline, and signatures from both parties — verbal agreements without written change orders are the leading source of payment disputes in solar contracting
The approval process follows a standard sequence: identification of the change, written change order with cost and timeline impact, customer review and signature, execution, and updated project documentation
Accurate upfront site assessment and design using solar design software can prevent 60–80% of change orders by identifying roof conditions, structural limitations, shading issues, and code requirements before the contract is signed

What Is a Change Order?

A change order is a written amendment to an existing solar installation contract that formally documents any modification to the project’s original scope, cost, or timeline. It becomes part of the contract once signed by both parties.

Change orders exist because no amount of pre-construction planning catches everything. A roof that looked solid in satellite imagery turns out to need sheathing replacement. The local AHJ adopts a new fire setback requirement between permit submission and inspection. The customer decides they want battery storage added after seeing their neighbor’s system. Each of these scenarios requires a formal change order — not a handshake, not an email, not a verbal agreement on the jobsite. Without a signed change order, the contractor absorbs unplanned costs, the customer disputes charges, and the project stalls. According to NREL soft cost research, change orders and rework account for 5–12% of total residential solar installation costs in the United States.

Change orders are standard practice across all construction disciplines. In solar, they carry additional weight because the permitting and interconnection processes are tightly coupled to the system design. A change to panel count, inverter model, or wire routing may require permit amendment, engineering revision, and utility resubmission — each adding cost and time.

Types of Change Orders

Site-Condition Changes

Discovered during installation when actual conditions differ from what was assessed during the site survey or satellite-based design. Examples include roof decking rot or damage requiring replacement before panel mounting, rafters that do not meet structural load requirements for the planned racking system, unexpected asbestos or lead paint on older homes, and electrical panels that lack sufficient capacity for the planned system. These are the most common type, accounting for roughly 40–50% of all residential solar change orders.

Customer-Requested Changes

Initiated by the homeowner or building owner after the contract is signed. Typical requests include adding battery storage to a PV-only system, increasing system size to offset a new EV or heat pump, changing panel placement for aesthetic reasons, upgrading to a different panel or inverter brand, or requesting a dedicated EV charging circuit alongside the solar installation. These changes often expand the project scope and require permit amendments.

Equipment Substitutions

Triggered by supply chain disruptions, manufacturer discontinuations, or lead time delays that make the originally specified equipment unavailable. The installer substitutes a comparable panel, inverter, or racking system. Even a direct swap to an equivalent product requires a change order because the new equipment may have different dimensions, weight, electrical characteristics, or warranty terms — all of which affect the engineering design, permit drawings, and interconnection application.

Code/AHJ-Required Changes

Mandated by the authority having jurisdiction during plan review, permit inspection, or final sign-off. Common AHJ-driven change orders include additional fire setback requirements that reduce the array size, rapid shutdown device additions or upgrades to meet NEC 2020/2023 requirements, grounding or bonding modifications, conduit routing changes to meet local fire code, and structural engineering stamps or load calculations not originally required. These are the hardest to prevent because code interpretations vary between inspectors and jurisdictions.

Change Order Comparison

Change Order Type	Typical Cost Impact	Timeline Impact	Who Initiates	Preventable?
Site-Condition Changes	$800–$3,500	3–10 days	Installer/contractor	Mostly — thorough site survey and accurate solar design software catch 70–80%
Customer-Requested Changes	$2,000–$15,000+	1–4 weeks	Customer	Partially — detailed upfront scoping and clear proposals reduce mid-project changes
Equipment Substitutions	-$500 to +$2,000	1–3 weeks	Installer/distributor	Partially — multi-vendor quoting and inventory buffers help
Code/AHJ-Required Changes	$500–$4,000	1–6 weeks	AHJ/inspector	Partially — pre-submission AHJ consultation and experience with local codes reduce surprises

Change Order Cost Formula

How to Calculate Change Order Cost

Change Order Cost = Material Delta + Labor Delta + Administrative Fee + Margin

Material Delta is the difference in equipment cost between the original specification and the revised specification. If new roof sheathing is needed, this includes plywood, fasteners, and flashing. If an inverter is substituted, it is the price difference between the two units. Labor Delta is the additional crew hours multiplied by the loaded labor rate — including travel time for return trips. Administrative Fee covers the cost of revised engineering, permit amendments, resubmissions, and project management time. Typical administrative fees run $150–$500 per change order. Margin is the contractor’s markup on the change order scope, typically 15–25%.

Example: An inspector requires the addition of a rapid shutdown device. Equipment cost: $350. Additional labor: 2 hours at $85/hour loaded rate = $170. Permit amendment fee: $75. Administrative time: $200. Subtotal: $795. With 20% margin: $954. The customer receives a change order for $954 with an itemized breakdown.

Accurate Upfront Design Prevents Most Change Orders

NREL’s soft cost benchmark studies consistently show that design-related rework is one of the largest contributors to residential solar soft costs. Companies that invest in accurate upfront site assessment — using high-resolution satellite imagery, detailed shade analysis, and structural pre-screening through solar design software — report 60–80% fewer change orders than companies relying on basic visual inspections and manual calculations. The cost of a thorough upfront design (30–60 minutes of designer time) is a fraction of a single change order. Every change order costs the installer not just in direct expenses but in schedule disruption, customer trust erosion, and crew redeployment overhead.

Practical Guidance

Run a full shade analysis before the contract is signed. Shading issues discovered during installation are one of the top causes of array redesigns and change orders. Use automated shading tools to identify obstructions that satellite imagery alone may not reveal clearly, such as nearby tree growth or planned adjacent construction.
Verify structural suitability in the design phase. Request site photos of the attic, rafters, and roof surface. Check rafter spacing and condition against the planned racking system’s load requirements. A $200 structural screening during design prevents a $2,000–$3,500 change order during installation.
Design to current AHJ requirements, not last year’s codes. Check the local jurisdiction’s adopted NEC edition and any local amendments before finalizing the permit set. Fire setback rules, rapid shutdown requirements, and grounding specifications vary by jurisdiction and change frequently.
Document every design assumption. Note the assumed roof type, rafter spacing, main panel capacity, conduit routing path, and equipment models in the design file. When a site condition differs from the assumption, the change order traces directly to a documented baseline rather than a verbal recollection.

Never proceed with out-of-scope work without a signed change order. Verbal approvals on the jobsite are the leading cause of payment disputes in solar contracting. If the crew discovers a condition that requires additional work, stop, document, price it, and get the customer’s written approval before continuing.
Photograph everything that triggers a change order. Take timestamped photos of the condition (damaged decking, undersized rafter, full electrical panel) before and after remediation. These photos protect the company if the customer disputes the charge and serve as documentation for warranty and insurance purposes.
Maintain a standard change order template. The template should include: original contract number, description of the change, reason for the change, itemized cost breakdown, revised completion date, customer signature line, and contractor signature line. A standardized form speeds up the process and ensures nothing is missed.
Track change order frequency by root cause. If 30% of your projects require a main panel upgrade change order, that signals your pre-sale electrical assessment is insufficient. Use change order data to improve your upstream processes, site survey checklists, and design workflows.

Set expectations about change orders during the sales process. Explain that unforeseen site conditions can occasionally require scope adjustments, and describe how your company handles them — transparent pricing, written documentation, customer approval before any additional work. Customers who are prepared for the possibility react far better than those who are blindsided.
Use detailed proposals to lock scope early. A solar proposal that specifies exact equipment, panel layout, electrical design, and site assumptions leaves less room for ambiguity. When the proposal clearly states “price assumes standard composition shingle roof with 2x6 rafters at 24-inch spacing,” the basis for any future change order is already established.
Price common contingencies into the original quote. If your historical data shows that 25% of projects need a main panel upgrade, consider including a contingency line item or offering the upgrade as a priced option in the original proposal. This reduces mid-project surprises and builds customer trust.
Frame change orders as protection for the customer. The change order process exists to ensure the customer is never charged for work they did not approve. Position it as a safeguard, not a hassle. Customers who view the process positively are more likely to approve necessary changes without friction.

Reduce Change Orders with Accurate Upfront Design

SurgePV’s satellite-based design, automated shade analysis, and AHJ-aware permit sets catch the issues that cause change orders — before your crew is on the roof. Design once, install once.

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Sources & References

Frequently Asked Questions

What causes change orders in solar installation?

The four primary causes are site conditions that differ from the original assessment (roof damage, structural deficiencies, undersized electrical panels), customer-requested changes after contract signing (adding battery storage, increasing system size, changing panel placement), equipment substitutions due to supply chain disruptions or manufacturer discontinuations, and code or AHJ requirements discovered during permitting or inspection (fire setbacks, rapid shutdown devices, grounding modifications). Site-condition changes are the most common, accounting for roughly 40–50% of all residential solar change orders. Most of these are preventable through thorough upfront design and site assessment.

How do change orders affect solar project cost?

A single change order on a residential solar project typically adds $1,500–$4,000 in direct costs, covering material differences, additional labor hours, administrative time for revised engineering and permit amendments, and contractor margin. Beyond the direct cost, change orders create indirect expenses: crew redeployment and scheduling disruption, customer communication overhead, and delayed interconnection that pushes back the system’s revenue generation start date. NREL research indicates that change orders and rework contribute 5–12% of total residential solar installation costs. For a $30,000 system, that translates to $1,500–$3,600 in avoidable expense per project.

How can solar companies reduce change orders?

The most effective approach is investing in accurate upfront design and site assessment. Use solar design software with high-resolution satellite imagery and automated shade analysis to identify roof conditions, structural limitations, and shading issues before the contract is signed. Request site photos of the electrical panel, attic space, and roof surface during the sales process. Consult with the local AHJ on current code requirements before submitting permits. Build a historical database of change orders by root cause and use it to improve site survey checklists and design assumptions. Companies that follow these practices report 60–80% fewer change orders compared to those that rely on basic visual assessments and manual design processes.