How to Choose a Commercial Solar Engineering Firm
Table of Contents
The engineering decision is one of the highest-leverage decisions on a commercial solar project. A weak plan set costs you 9 to 27 weeks and thousands in resubmission fees. The wrong firm costs you more than that in change orders, failed inspections, and phone calls to get someone to fix what should have been right the first time.
Most EPCs choose engineering firms on price and turnaround time. Both matter, but neither tells you whether the firm can actually do the work. Here are five questions that do.
1. Is Every Project Stamped by a Licensed PE?
This is the floor. Not a consultant who signs off at the end. Not a draftsperson who produces drawings and routes them to a PE for a signature. A licensed professional engineer who is involved in the design and takes legal responsibility for the stamp.
At Jolt Engineering, every commercial project gets a licensed PE on the stamp. No residential overflow. No high-volume processing where projects are batched through review.
2. Do They Work Commercial-Only, or Do They Also Do Residential?
Commercial and residential solar engineering are different disciplines. Commercial projects involve larger systems, more complex AHJ review processes, and utility requirements that differ substantially from residential permit workflows.
A firm that does both often routes commercial projects through processes designed for residential volume. The plan set looks like a residential drawing with larger numbers. AHJ reviewers notice.
Ask: "What percentage of your work is commercial?"
If the answer is below 80%, ask why. Firms that work exclusively on commercial projects build the institutional knowledge that prevents rejections. They know which AHJs require specific callouts, which utilities run their own interconnection checklist that differs from the state standard, and which requirements are common to the types of buildings you are putting systems on.
Jolt is commercial-only. Has been since 2017.
3. Are They Licensed in Your Project State?
A PE stamp from an engineer not licensed in the project state is not valid. This sounds obvious, but it is a frequent resubmission reason, particularly when an EPC works in multiple states and uses a firm that is licensed in some of them but not all.
Ask: "Are you licensed to stamp drawings in [state]?"
Follow up by verifying through the state's licensing board if the project is large. State licensing databases are public and show active status, license number, and license type.
Jolt is licensed across key commercial solar markets. If you are building in a state where we hold a license, we can stamp. If you are building in a state where we are not licensed, we will tell you.
4. What Is Their Correction Rate on First Submissions?
This is the number most firms will not quote you directly. Ask anyway.
A first-submission approval rate is the clearest measure of plan set quality. A firm that consistently clears AHJ review on the first submission has engineers who know what reviewers look for, who prepare complete packages, and who validate before they submit.
A firm with a high correction rate is producing plan sets that look good but do not hold up under review. You pay for the resubmission in time and money.
Ask: "What percentage of your commercial submittals are approved on first submission?"
If they cannot answer, that is an answer. If they say "we rarely get corrections," ask what their most common correction reasons are. A firm that has worked through corrections knows what they are. A firm that says they never get corrections is not tracking or not being honest.
83% of inspected commercial solar projects show wiring and connector issues. PE-stamped engineering that catches field coordination problems before permit submission dramatically reduces that rate. The difference is visible in the first-submission approval numbers.
5. How Do They Handle Field Changes?
Things change in the field. Equipment gets substituted. Structural conditions differ from what the drawings assumed. Roof access changes. What matters is what happens next.
Ask: "If we need a field change that affects the design, what is your process?"
The answer should include a specific person to contact, a turnaround expectation, and a process for issuing revised drawings if necessary. If the answer is vague, "just let us know and we'll handle it," that is not a process. That is a hand wave.
The engineer of record needs to review and approve equipment substitutions before the field team installs them. Swapping modules or inverters without engineering review is how projects fail final inspection. A firm with a clear field change process has dealt with this enough to have built a system around it.
What to Do With the Answers
These five questions will surface the firms that are worth working with. The right answers are specific, verifiable, and consistent across the firm's principals and PMs.
Most firms will give you a version of "yes, we do all of that." Push past the answer to the process. How does the PE get involved? What is the actual first-submission rate from the last 12 months? What is the name of the licensing board where you can verify their stamp?
Firms that have done the work can answer these questions without hesitation.
Ask us these questions. We will answer all of them: joltengineering.com/commercial-solar-engineering
Founder & Principal of Jolt Engineering. 17+ years in commercial solar. Spent a decade on the EPC and client side before founding Jolt in 2017 to solve the problems he experienced firsthand.
