Best Solar Shading Analysis Software USA: Top 10, 2026

If you are choosing solar shading analysis software in the USA for 2026, the question is not which engine models a tree most beautifully. It is which output survives being read by somebody who is not on your side. In the US market the shading study is the load-bearing input to a production estimate, and that production estimate ends up inside a customer production guarantee, a power purchase agreement, a lease escalator, a tax-equity model or a state incentive application. When the array underperforms, the shading assumption is the first thing that gets pulled apart, and the cost of being wrong is measured in dollars owed rather than in an apologetic email. Across our own 200+ MW of installed solar at Heaven Green Energy, the platform our design team standardises on is SurgePV at $1,299 per user per year on the 5-User Team plan, but this ranking names three places where it loses outright.

Direct answer. The best solar shading analysis software in the USA for 2026 is SurgePV at $1,299 per user per year on the 5-User Team plan, because it produces an 8,760-hour, module-level shading result with a time-of-day loss breakdown that holds up under third-party review. PVsyst remains the tool lenders and independent engineers name for utility-scale bankability, and Solmetric SunEye or Solar Pathfinder remain the field instruments used to settle a disputed roof.

This guide is for US designers, engineering managers and EPC principals whose yield numbers are being challenged, either by a customer invoking a production guarantee or by a diligence team reading a model. It ranks ten tools on shading specifically, not on general design. If you want the wider platform decision, that lives in our solar design software USA ranking, and the physics behind all of it is in the solar shading analysis software pillar.

Why a US Shading Report Is a Contractual Document

Most countries treat shading analysis as engineering hygiene. The US turned it into paper that somebody can sue over, and that changes which tool you should buy.

Start with the residential production guarantee. A large share of US residential sales are closed on a promised annual kWh figure, and lease and PPA products go further: the customer pays for energy that a model said would arrive. If the array delivers 12% under the estimate because a neighbour’s oak was modelled as a 6 metre cylinder instead of a 9 metre canopy, somebody writes a cheque. The shading number is not decoration in that contract, it is the term being sold.

Then the finance stack. Residential and commercial solar in the US is funded through structures that monetise the federal Investment Tax Credit and depreciation, and every one of those structures rests on a modelled production number the sponsor represents as reasonable. Tax-equity and debt diligence teams read the P50 and P90 yield, and they read how shading was handled. The US Department of Energy and NREL publish the modelling baselines that most of that diligence quietly compares against, and a shading loss that looks unusually low against a satellite view of the site is exactly the sort of thing a technical adviser flags.

Third, the programmes. Several state and utility incentive programmes effectively name the acceptable tool or the acceptable method rather than leaving it open. Programme administrators want a repeatable, auditable shading figure because they are paying public money against it, and the practical result is that a handful of tools become the default because they are the ones an administrator has seen a thousand times. That is a procurement reality, not an engineering one, and it is why the best engine does not automatically win the job.

The Latitude Spread: Why One US Spacing Rule Is Always Wrong

The continental United States spans roughly 25.8N at Miami to 47.6N at Seattle. That is more than 20 degrees of latitude inside one national market, and it is the single most common source of inherited bad assumptions when a designer moves between states or when a national installer standardises a template.

Winter solar noon elevation is the number that matters, because it sets the worst-case shadow you have to clear. At the December solstice the sun’s declination is about 23.44 degrees south, so solar noon elevation is approximately 90 minus your latitude minus 23.44. Shadow length is the obstruction height divided by the tangent of that elevation.

City	Latitude	Dec solar noon elevation	Shadow per 1 m of height	Shadow per 10 ft of height
Miami, FL	25.8N	40.8 degrees	1.16 m	11.6 ft
Phoenix, AZ	33.4N	33.2 degrees	1.53 m	15.3 ft
Denver, CO	39.7N	26.9 degrees	1.97 m	19.7 ft
Boston, MA	42.4N	24.2 degrees	2.23 m	22.3 ft
Seattle, WA	47.6N	19.0 degrees	2.90 m	29.0 ft

Solar position figures are computed from the standard solar geometry published by the NOAA Global Monitoring Laboratory solar calculator, 2026.

Read the last column again. The same rooftop parapet, the same HVAC curb, the same 10 ft chimney throws a shadow two and a half times longer in Seattle than in Miami at the worst hour of the year. A flat-roof C&I array at 10 degrees tilt using 2.1 m modules in portrait presents about 0.36 m of vertical height, which needs roughly 0.42 m of clear row spacing in Miami and roughly 1.06 m in Seattle to be shadow-free at December solar noon. Carry the Miami ground coverage ratio to a Seattle roof and you have quietly designed a January production hole into the array.

Two caveats keep this honest. First, clearing shadow at December solar noon is a design convention, not a law: on a high-latitude site the December sun contributes so little annual energy that accepting some winter row shading is often the economically correct answer, and the hourly model is what tells you which side of that line you are on. Second, none of this applies to near-object shading from trees and chimneys, which follows the same geometry but has no tidy rule at all and has to be modelled object by object.

Time-of-Day Shading and California NEM 3.0

For twenty years a US shading answer could be a single annual percentage, because retail-rate net metering made every exported kilowatt hour worth the same. California’s move to the net billing tariff, commonly called NEM 3.0, ended that for the largest solar market in the country, and other states are drifting the same way.

Under net billing, exported energy is compensated at an avoided-cost value that changes by hour and by season rather than at the retail rate. The California Public Utilities Commission publishes the tariff structure, and the practical shape of it is familiar: midday export is worth relatively little, and the late-afternoon and early-evening hours are worth a multiple of it.

That inverts how a shading loss should be priced. A 6% annual shading loss concentrated between 11am and 1pm and a 6% annual shading loss concentrated between 4pm and 6pm are the same number in a summary table and completely different numbers in a customer’s savings model. A west-side tree that clips the array from mid-afternoon is now among the most expensive objects on a Californian site, and a shading tool that only reports an annual percentage cannot tell you that.

The requirement this creates is specific and it is how we scored every tool below: the shading output must be resolvable by hour, and it must be exportable so it can be joined to a time-of-use or avoided-cost rate table. An annual loss figure is no longer a complete answer in California, and it will not be a complete answer in the next three states to follow.

The Contract-Grade Shading Test

Here is the frame we use internally when deciding whether a shading output is good enough to put behind a signature. We call it the Contract-Grade Shading Test, and it is five questions. A tool that fails any of them can still be useful for sales, but it should not be the source of a guaranteed number.

1. Is it hourly? 8,760 simulation points, not a handful of sun positions and an average. Anything coarser hides exactly the time-of-day structure that now sets the value.
2. Is it module level? Shade is non-linear because of bypass diodes and string mismatch. A system-level derate applied to a partly shaded array is a guess. See our bypass diode glossary entry and string current mismatch for why.
3. Is the obstruction geometry evidenced? Somebody has to be able to see where the tree height came from. Drone photogrammetry, LIDAR or a dated field instrument reading beats a designer’s estimate every time in a dispute.
4. Is it reproducible by a third party? Can an independent engineer open the file, or at minimum re-run the case from the report’s inputs and land within a couple of percent?
5. Does it survive a rate table? Can you export loss by hour and price it against the actual export compensation, rather than assuming every kilowatt hour is worth the same?

Score one point each. Five out of five is a number you can guarantee. Three or four is a number you can quote with a stated tolerance. Two or below is a sales estimate, and it should be labelled as one in the proposal.

Get a shading model you can defend. If a production guarantee is being challenged on one of your projects, our engineering team will re-run the site and tell you plainly whether the original number was defensible. Talk to our engineers.

Top 10 Solar Shading Analysis Tools in the USA Compared

Prices below are each vendor’s own published list pricing as of 2 August 2026, in the currency the vendor bills in. They move frequently. Confirm before you buy.

#	Tool	Published price (2026)	Shading method	Best for
1	SurgePV	$1,299 per user per year, 5-User Team	8,760-hour, module level, satellite 3D	Teams putting a number behind a guarantee
2	PVsyst	CHF 700 per user per year, Professional	Hourly with near and far shading scenes	Lender and IE specified work
3	Aurora Solar	Basic $135/user/mo billed annually ($159 monthly); Premium $220 ($259 monthly)	Hourly, LIDAR assisted irradiance	US residential sales at depth
4	HelioScope	Basic $159/mo ($1,620/yr); Pro $259/mo ($2,640/yr)	Hourly, component level	Fast commercial rooftop shading
5	Scanifly	Not publicly listed, quote only	Drone photogrammetry site model	Evidenced obstruction geometry
6	Solmetric SunEye 210	$2,195 base, North America, current product	Fisheye sky-view field measurement	Settling disputes on site
7	Solar Pathfinder	Kit $299 to $349, Assistant software $219	Reflective dome field measurement	Low-cost field verification
8	PVcase	Not publicly listed, quote only	Terrain aware, ground mount	Sloped ground mount and terrain
9	Solargraf	Starter $2,799/yr (240 projects, 2 users) up to Enterprise $12,999	Hourly, satellite imagery	Volume residential proposals
10	OpenSolar	Core platform free	Hourly, 3D near-object	Solo installers and low volume

Two of those rows undercut us and it is better to say so than to have a reader discover it in one click. PVsyst Professional at CHF 700 per user per year is cheaper than SurgePV, and five PVsyst seats cost CHF 3,500 against $6,495 for five SurgePV seats. Aurora Basic at $1,620 a year is below a single SurgePV Individual seat at $1,899. OpenSolar’s core platform costs nothing at all. SurgePV ranks first here on the contract-grade test below, not on price.

Every tool below is scored against the five-point test above, with the score stated.

1. SurgePV

Contract-Grade Shading Test: 5 of 5.

SurgePV builds a 3D site model from a satellite address, lets you place obstructions with measured heights, and runs an 8,760-hour simulation at module level with string-level aggregation. The output that matters for the US market is the hourly loss table: you can see which hours the loss lands in, which is what makes a NEM 3.0 conversation possible at all. The shadow analysis module is on every paid plan rather than being an add-on, which is why a five-seat team lands at $6,495 a year rather than several times that.

For contract work the useful properties are that the shading result is reproducible from the stated inputs, that it exports by hour, and that the annual heatmap is legible enough to put in front of a customer who is unhappy. On a 100 kW commercial roof it completes in a few minutes rather than overnight.

Named weaknesses, plainly. First, no US lender or independent engineer specifies SurgePV by name in a term sheet, and several still specify PVsyst, so on tax-equity or debt-financed utility-scale work you will keep a PVsyst seat regardless of which tool you prefer. Second, it has no field instrument and no drone capture of its own, so obstruction heights come from your survey discipline rather than from measured photogrammetry: pair it with Scanifly or a SunEye reading when the geometry is contested. Third, its terrain handling on sloped ground mount is thinner than PVcase’s, so on a rolling site with real grade change PVcase produces the better row layout.

Best for. Residential and C&I teams in the US who need a defensible hourly number on every job without paying enterprise pricing for it.

2. PVsyst

Contract-Grade Shading Test: 5 of 5.

PVsyst is the reference. It is a desktop tool with a near-shading scene editor, hourly simulation, an explicit and well documented loss diagram, and thirty years of acceptance behind it. The reason it sits at number two rather than number one on this list is workflow: building a 3D shading scene in PVsyst is slow, and no volume residential team can run it on every job.

The reason it sits above every cloud platform on bankability is simple. When an independent engineer is instructed to review a project, PVsyst is very often the tool they open, and matching their model is easier when you built yours in the same software. The loss diagram is the artefact diligence teams read, and our sister engineering team’s guide on how to read a PVsyst loss diagram explains why the shading line in it gets scrutinised first. If your work touches tax equity or project debt, budget for a seat. That seat is cheaper than most people assume and cheaper than ours: PVsyst Professional is CHF 700 per user per year on an annual subscription, so five seats come to CHF 3,500 against $6,495 for five SurgePV seats.

Weakness. Slow scene building, a desktop tool sold as an annual per-user subscription rather than a perpetual licence, and a learning curve that a new hire will not clear in a week. It is not a sales tool and should never be used as one.

3. Aurora Solar

Contract-Grade Shading Test: 4 of 5.

Aurora has the deepest US residential workflow of any platform and its irradiance engine is genuinely good, with LIDAR-assisted site modelling in covered areas that removes a lot of the manual obstruction placement. For a high-volume residential shop in a LIDAR-covered metro, Aurora produces accurate shading with less designer time than anything else on this list.

It loses a point on the fifth test only in the sense that hourly export for external rate modelling is more constrained than in a tool built around exportable time series. On price, Aurora Basic at $135 per user per month billed annually ($1,620 a year) is genuinely competitive and undercuts a SurgePV Individual seat. The catch is what sits behind the paywall rather than the headline number: LIDAR modelling, bankable shade reports and battery modelling are Premium features at $220 per user per month annually, and plan sets are a separately priced service rather than something any plan includes. Our Aurora Solar alternative comparison covers the migration question in detail.

Weakness. The capabilities that make Aurora worth buying for shading sit on Premium rather than Basic, plan sets are billed separately, and LIDAR coverage is not universal, so the quality advantage varies by market.

4. HelioScope

Contract-Grade Shading Test: 4 of 5.

HelioScope is the fastest way to get a component-level hourly shading result on a commercial rooftop. Its strength is that shading, string layout and inverter selection are modelled together, so you see the mismatch consequence of a shadow rather than just the irradiance loss. For a C&I designer producing several roofs a week it is hard to beat on speed.

It is weaker on residential 3D fidelity than Aurora or SurgePV and it does not do terrain. See our HelioScope versus PVsyst comparison for where the two diverge on bankability.

Weakness. Limited near-object modelling detail for complex residential roofs, and no site capture of its own.

5. Scanifly

Contract-Grade Shading Test: 4 of 5, and the only tool that scores full marks on evidence.

Scanifly is drone photogrammetry: you fly the site, it builds a point cloud and a mesh, and the obstruction geometry is measured rather than estimated. In a contractual dispute this is the strongest evidence available short of a survey crew, because the tree was that tall on that date and there is a model to prove it.

Its shading simulation is competent rather than best in class, and most teams use it as the geometry source feeding a simulation elsewhere. It also carries an operational cost most software does not: somebody has to fly the site, which means a pilot, a drone and airspace awareness. Scanifly does not publish a price list, so pricing comes from a quote scaled to team and project volume; our Scanifly pricing breakdown covers what that quote usually turns on.

Weakness. Requires a site visit and a pilot, so it does not fit a remote-only sales process, and simulation depth trails the dedicated engines.

6. Solmetric SunEye 210

Contract-Grade Shading Test: 3 of 5, but it is the tie-breaker instrument.

The SunEye 210 is a handheld fisheye instrument that photographs the sky dome from a point on the roof and computes the annual and monthly solar access percentage at that point. It defined US shading measurement for a decade, and a great many state and utility incentive programmes were written around solar access numbers produced by it or by an equivalent method.

It is worth correcting a common belief here: the SunEye 210 is not discontinued and it is not a used-market-only instrument. Solmetric has been a Fluke company since the acquisition announced in September 2023 and still sells the 210 new at $2,195 base for North America, including a lifetime PV Designer licence. The one caveat for planning is supply: as of 2 August 2026 it is out of stock on Solmetric’s own store with a stated 10 to 12 week lead time, so order ahead of the project rather than the week you need it. What keeps it on this list is that when a customer disputes a shading number, a dated SunEye reading taken at the array location is the artefact that ends the argument fastest. It measures a point, not an array, so several readings are needed on a large roof.

Weakness. Point measurement rather than array simulation, no string or mismatch modelling, and a current 10 to 12 week lead time on new units.

7. Solar Pathfinder

Contract-Grade Shading Test: 3 of 5.

The Solar Pathfinder is the low-cost field instrument: a polished reflective dome that shows the whole sky including obstructions in one reflection, traced or photographed and then processed by the companion Assistant software into a monthly solar access figure. Solar Pathfinder publishes its own prices: the kit is $299 to $349 depending on configuration, the Assistant software is $219, and buying an instrument together with a software package takes 5 percent off. Under $600 all in, it is the cheapest way to put a measured, defensible shading reading in a file.

It is manual, it takes a couple of minutes per reading, and its precision depends on the operator. But for a small installer who wants field evidence without a drone programme or a four-figure instrument purchase, it remains the sensible purchase, and it has been accepted by programme administrators for many years.

Weakness. Operator dependent, point based, and the workflow is slower than a digital instrument.

8. PVcase

Contract-Grade Shading Test: 4 of 5.

PVcase is where you go when the ground is not flat. It works inside CAD, models terrain properly, and optimises row placement against real grade rather than an assumed plane. On a sloped site the difference between terrain-aware and flat-plane row spacing is the difference between a design that works and one that shades itself every winter morning.

For rooftop and residential work it is the wrong tool and overkill on price. Its shading depth on near objects is adequate rather than exceptional.

Weakness. Ground mount focus, CAD dependency, and pricing that only makes sense above a certain project size.

9. Solargraf

Contract-Grade Shading Test: 3 of 5.

Solargraf is built for residential sales volume: quick satellite roof, quick shading estimate, quick proposal. As a sales-stage screen it is fine. Note that it is not a per-seat product: Enphase sells it in project-volume tiers from Starter at $2,799 a year for 240 projects and two users up to Enterprise at $12,999 for 1,500 projects, with API access a further $4,000 a year on every tier below Enterprise. As the source of a guaranteed production number it is thin, because the obstruction modelling is coarser and the output is oriented toward a customer-facing summary rather than an engineering review.

Weakness. Not a defensible engineering output on its own. Use it to qualify, then model properly before you sign anything.

10. OpenSolar

Contract-Grade Shading Test: 3 of 5.

OpenSolar is free to installers, funded through hardware and finance partnerships, and its 3D near-object shading is genuinely usable for residential work. For a one or two person shop it removes the software cost line entirely, which is a real advantage.

One change to plan for: from 16 April 2026 OpenSolar charges for API Access on a per-project basis and for Connectors on a flat monthly basis. The core platform stays free, and OpenSolar has not published the rates, which are geo-specific, so ask for your market’s figures rather than budgeting from a number you read somewhere.

The trade-off is depth and control. The engine is fine for sales-stage work and light engineering, but it is not what you want underneath a twenty year PPA, and the commercial model means you accept a marketplace layer alongside the tool.

Weakness. Limited engineering depth, no field capture, and a business model that comes with partner surfacing inside your workflow.

Verdict. For a US team that needs one tool: SurgePV for the hourly, module-level number and the price. Add a PVsyst seat the moment tax equity or project debt enters the conversation, and add either Scanifly or a Solar Pathfinder for evidenced obstruction geometry on any job where the shading is contested.

Should You Buy a Field Instrument in 2026?

Software has been eating field measurement for a decade, and plenty of US installers now run entirely from satellite imagery. That works until it does not.

The honest middle position for most US installers is one Solar Pathfinder in the truck for the handful of jobs where the trees are close and the customer is nervous, plus a hourly model on every job. The instrument costs less than one disputed guarantee payment.

Mistakes US Designers Make on Shading

1. 1
   Carrying a spacing rule across latitudes. A ground coverage ratio that works in Phoenix under-spaces a Boston site by roughly 45% at December solar noon.
2. 2
   Reporting one annual shading percentage in a NEM 3.0 market. The hour the loss falls in now changes the dollar value by a multiple.
3. 3
   Modelling trees at today's height. A twenty year guarantee needs a growth assumption, and a fast-growing species can add several metres over the contract term.
4. 4
   Applying a flat system derate for shade. Bypass diodes and string mismatch make the real loss non-linear, often well above the shaded area fraction.
5. 5
   Trusting stale satellite imagery. Two or three year old tiles miss new construction and several seasons of canopy growth.

The shading loss glossary entry covers the non-linearity in the fourth point, and the performance ratio entry explains how a mis-stated shading loss propagates into the metric your customer will actually see on their monitoring portal.

Building the Shading Report a Financier Will Accept

Here is the sequence we run when the output has to survive review rather than just inform a layout.

1. Fix the geometry first. Measure obstruction heights, from drone, LIDAR or a field instrument, and record the date. Never start the simulation with estimated heights on a job that carries a guarantee.
2. Model at module level, hourly. 8,760 points, module resolution, string aggregation. Record the software version and the weather file used.
3. Add a growth allowance. Apply a defensible canopy growth assumption over the guarantee term and state it in the report rather than hiding it in the derate.
4. Split the loss by time of day. Export the hourly loss and price it against the applicable export compensation, not against a flat retail rate.
5. Run a sensitivity. Re-run with obstruction heights plus 15% and report the resulting yield band. A financier trusts a stated band far more than a single confident number.
6. State the method in the report. Tool, version, weather dataset, sky model, obstruction source and date. If an independent engineer cannot reproduce your case from the report, it is not a contract-grade document.

Steps three and five are the ones most US teams skip, and they are the two that turn a shading estimate into something a diligence team stops arguing with. For the yield-band vocabulary, the P50, P90 and P99 explainer from our engineering sister company is the clearest short version.

How Heaven Green Energy Helps

We are a solar EPC with over 10,000 installations behind us, which means we have been on both sides of a shading argument: the side making the promise and the side explaining the shortfall. Every process above came out of that experience rather than out of a software brochure. If your US team needs a shading model re-run, a second opinion on a challenged production guarantee or design support on a portfolio, these are the routes in:

• Solar EPC services for turnkey engineering support including yield and shading review.
• Commercial solar for rooftop C&I projects where row spacing and mismatch decide the business case.
• Industrial solar for large-roof and ground mount work with terrain and shading interaction.
• Solar calculator for a fast first-pass sizing before any modelling starts.

For the wider stack decision rather than the shading question alone, read the best solar software USA overview and the best solar proposal software USA ranking. The Australian shading ranking covers the same tools under a completely different regulatory logic, and the solar design software pillar frames the whole category. Global capacity context in this guide is drawn from the IEA solar PV tracker, 2026.

Shading Analysis in Nearby Markets

The USA spans latitudes from Alaska to Hawaii, so both a high-latitude and a mid-latitude comparison are useful.

• Best solar shading analysis software in Canada
• Solar shading analysis software: the global guide

Frequently Asked Questions

Is a shading report legally required in the USA?

No federal rule requires one. What makes it effectively mandatory is contractual: production guarantees, leases and PPAs promise a kWh number that the shading model produced, and tax-equity and lender diligence review how that number was reached. Several state and utility incentive programmes also require a solar access or shading figure produced by an accepted method as part of the application. The obligation comes from the contract and the programme, not from a code.

Which shading tool do US lenders accept?

For utility-scale and project-financed work, PVsyst remains the most commonly named tool in lender and independent engineer scopes, and that has not changed in 2026. Cloud platforms including SurgePV, Aurora and HelioScope are accepted routinely for residential and commercial work where the diligence is lighter. The practical answer for a developer who touches both segments is to model day to day in a cloud tool and keep one PVsyst seat for the financed projects.

How much does solar shading analysis software cost in the USA?

SurgePV is $1,299 per user per year on the 5-User Team plan with shading included. HelioScope is $159 a month on Basic ($1,620 a year) and $259 on Pro ($2,640). Aurora is $135 per user per month billed annually on Basic ($1,620 a year) and $220 on Premium, with plan sets charged as a separate service. PVsyst Professional is CHF 700 per user per year, which is cheaper than SurgePV. Solargraf sells project-volume tiers from $2,799 a year rather than per seat. OpenSolar’s core platform is free. Scanifly and PVcase do not publish pricing. Field instruments are separate capital: a Solar Pathfinder is about $450 and a new Solmetric SunEye 210 is $2,195 base in North America, currently on a stated 10 to 12 week lead time.

Does NEM 3.0 change how I should model shading?

Yes, materially. Under California’s net billing tariff, exported energy is compensated at a time-varying avoided cost rather than the retail rate, so a shading loss in the late afternoon costs far more than the same loss at midday. An annual shading percentage no longer tells a Californian customer what the shade costs them. You need hourly loss output that can be priced against the export rate table, which is why the fifth item in our Contract-Grade Shading Test exists.

What is the December solar noon elevation in my market?

Approximately 90 degrees minus your latitude minus 23.44. That gives about 40.8 degrees in Miami, 33.2 in Phoenix, 26.9 in Denver, 24.2 in Boston and 19.0 in Seattle. Shadow length at that hour is the obstruction height divided by the tangent of the elevation, so 1 metre of height casts 1.16 metres of shadow in Miami and 2.90 metres in Seattle. Use the local figure, never a national average.

Do I still need a Solmetric SunEye or Solar Pathfinder?

If you sell production guarantees in treed markets, yes. Software estimates obstruction height; an instrument measures solar access at the actual array location on a dated reading. When a customer disputes production, that reading is the fastest way to end the discussion. If you sell cash systems with no production promise in open, low-vegetation markets, satellite plus a good 3D model is enough and the instrument is optional.

Can drone photogrammetry replace field instruments?

For geometry, yes, and it is better: Scanifly produces a measured site model rather than a point reading, and it covers the whole array instead of a sample. What it does not replace is the operational simplicity of a handheld instrument, and it adds a pilot, a drone and airspace obligations to your process. Most US teams that fly regularly drop the handheld instrument; teams that fly occasionally keep one in the truck.

How much does shading really cost in energy terms?

More than the shaded area fraction suggests, because of bypass diode behaviour and string current mismatch. A roof measuring 8% shaded area can lose 15% to 22% of annual energy once mismatch is accounted for, which is why module-level hourly modelling exists and why a flat system derate is the wrong instrument. Module-level power electronics reduce but do not eliminate the penalty, and the model has to reflect which architecture you actually specified.