I got quotes from three solar installers…

When I priced out my 6.4kW solar install with three different contractors, the quotes came in at $24,000, $27,500, and $31,000. After the 30% federal tax credit, the best quote was about $16,800. The equipment cost me $7,200 buying direct (Silfab panels, Enphase IQ8 microinverters, racking). That's a $9,600 difference — roughly $800/month for a year of evenings and weekends.

I'm an electrical engineer, so I'm not a typical DIYer. But I've since helped three neighbors do the same thing and none of them are EEs. Let me break down what's genuinely hard and what's just unfamiliar.

The hard parts (genuinely difficult)
Roof structural assessment: you need to confirm your rafters can handle the added snow load + panel weight. This usually means pulling an attic access and measuring. If you have any doubt, get a structural engineer to look — it's $200–400 for peace of mind.

Interconnection agreement with your utility: this is bureaucratic, not technical, but it can be slow (6–16 weeks in some jurisdictions) and you cannot legally energize your system until it's approved. Plan for this.

Final inspection: your local AHJ (authority having jurisdiction) will inspect the install. Code requirements vary by jurisdiction — know your local codes before you start. The NEC 2020 requirements for arc-fault protection, rapid shutdown, and labeling are the ones that catch people.

The unfamiliar parts (scary but learnable)
High-voltage DC wiring: solar panels in series can produce 400–600V DC. This is genuinely dangerous and requires respect, but it's not complicated — it's just wire. Use the right connectors (MC4), pull them correctly, and don't disconnect under load.

Roof penetrations: flashing a roof mount properly is a learned skill but not rocket science. Watch some installation videos, use proper flashing kits (Ironridge L-foot with Quickmount PV seal), and don't cheap out on the waterproofing.

The result
My system has been running for 18 months. It passed first-time inspection. Production is tracking within 3% of my PVWatts estimate. Total DIY cost including all materials, tools I didn't own, and permit fees: $8,100. Post-tax-credit: $5,670. Payback at my electricity rates: 5.8 years.

The contractor quote would have been $16,800 post-credit with an estimated 12-year payback. Would I do it again? Without question.

The one thing I'd caution: don't do this if you're not comfortable on a roof, don't want to spend time learning the electrical code, or don't have a patient personality for bureaucratic delays. The savings are real but so is the time investment.

Anyone else done a DIY install? What was your inspection experience like?

The hardware economics here are sound and the $9,600 savings figure is accurate as far as it goes. What DIY solar analyses almost always omit is the implicit hourly rate being applied to the labor.

The author mentions "evenings and weekends for a year." A project of this scope — permit research, equipment sourcing, structural assessment, roof work, electrical rough-in, interconnection paperwork — typically runs 100–150 hours for a first-time builder. At the $9,600 savings figure, the effective labor rate is $64–96/hour. That's a perfectly defensible trade if those hours have limited alternative value. It's a poor trade if you're foregoing billable work at $120+/hour to do it.

The calculation I'd recommend for anyone evaluating this: what's your realistic hourly rate for the specific evenings and weekends you'd use? Not your professional rate — your rate during the discretionary hours you'd actually be doing this work. For most people that number is much lower than their professional rate, which is why the DIY route pencils out more often than the raw hourly comparison implies.

What the analysis correctly identifies, without quite saying it explicitly: the hardware markup in professional installation quotes is real, repeatable, and not tied to your labor value at all. A well-specified direct-purchase system consistently comes in at $2,500–3,500/kW less than contractor-installed in my analysis of quotes from this forum and others. That gap is the durable financial case for DIY — independent of how you value your time.

As someone who does solar installations professionally, I want to offer a nuanced take here rather than getting defensive. The DIY route genuinely works for people with the right combination of skills, time, and patience. What I tell homeowners who ask about it:

The money saved is real. The risk is also real — not usually from the installation itself, but from the gotchas: is your roof in good enough shape that you won't need to remove panels for a re-roof in 5 years? Is your electrical panel sized correctly for the interconnect? These are things an experienced installer checks automatically that DIYers sometimes miss.

Also: most microinverter and equipment warranties require professional installation. Enphase IQ8 warranty is voided by DIY install in some markets. Check this carefully before buying.

I've guided four students through DIY installs as extended-year projects. Every one passed first-time inspection. The permit bureaucracy is genuinely the hardest part — not the electrical work. And once you've done a permit application once, the second install is dramatically faster to navigate.

The rapid shutdown requirement (NEC 2020 690.12) is the one that surprises most DIYers. Every US roof-mounted system must now have a rapid shutdown device that de-energizes the conductors on the roof within 30 seconds of a signal from inside the building. Enphase IQ8 microinverters have this built in (they communicate over the power line). String inverters require a separate rapid shutdown device at the array. This adds $200–400 to the BOM for string inverter systems and is often missed in DIY price comparisons.

What racking system did you use and would you recommend it? I see Ironridge and Unirac come up a lot. Also — did you hire the structural engineer for roof assessment or did you wing it?

Unirac SFM Infinity is what I spec on commercial jobs — excellent engineering and very strong pan-tilt options. For residential DIY, Ironridge XR100 is the better choice: better span table tools, wider availability at distributors, stronger DIY community documentation online. Both are good; Ironridge wins on the DIY support ecosystem.

Oregon has a self-certification path for residential solar under 10kW through many AHJs — it skips the full plan review and compresses the permit timeline significantly. Worth a five-minute call to your building department before you start the application. It saved me about six weeks on my 4kW install last year.

I used Ironridge XR100 (standard roof mount). It's solid, well-documented, and widely used. The online span table tools make it easy to spec correctly. Unirac is equally good. The cheap offshore racking I've seen on some systems concerns me — the anodizing is thinner and I've seen corrosion at 5–7 years. Pay the extra $200 for a real brand.

I did hire a structural engineer, paid $275, and he signed off the same day. Absolutely worth it for peace of mind and I included his letter in the permit package which the inspector appreciated.

HOA angle in Texas: even with a city permit, my exterior electrical variance requirement adds 60–90 days and a formal board vote. Three solar installs have gone through my board this year. The technical install is the easy part. If you're in a governed community, start the board approval process before you buy anything.

I got quotes from three solar installers, then DIY'd it anyway