Solar Contractor Estimating

We split the takeoff at the inverter. The DC side includes modules, string combiners, DC disconnects, and PV wire. The AC side includes inverter output, AC disconnect, panelboard, and transformer. Each side gets its own sheet and labor crew. This prevents the common error of pricing a single per-watt number that hides the AC interconnection gear, which can be a significant portion of the cost. For example, a 500 kW commercial system might have $0.10/W in AC gear alone. We also separate the utility interconnection items, such as the visible-break disconnect and production meter, so you can see the full AC scope.

Waste factors vary by component. For modules, we typically add 1 to 2 percent for breakage and future service. For racking rails, 5 percent for cuts and splices. For conductors, 10 percent for pulls and slack. Conduit waste is 5 percent. These are carried as separate lines so you can adjust them based on your own historical data or project conditions. For example, on a 1 MW ground-mount, 2% module waste equals 20 modules, which is a significant cost. We also add waste for flashing and attachment hardware, typically 3%.

Yes. If the project includes battery storage or EV chargers, we take off those loads separately from the PV array. This includes additional inverters, transfer switches, panelboards, conduit, and conductors. We price them as options so you can see the incremental cost. This also helps you evaluate whether the service size needs an upgrade. For battery storage, we include the battery modules, racking, and thermal management. For EV charging, we include the dispensers, load management system, and ADA compliance items. These are often omitted from the base PV bid.

We check the single-line diagram against the adopted NEC edition. If rapid shutdown is required at the module level, we add module-level electronics and labeling as a line item per module or per string. If at the string level, we add a disconnect at the array. The exact requirement depends on the code edition, which you should confirm with the local building department. For example, NEC 2017 requires rapid shutdown at the array boundary, while NEC 2020 requires module-level shutdown for rooftop systems. This can add $0.05 to $0.10 per watt to the DC side.

Most solar takeoffs are completed in 24 to 48 hours. Rush service is available for bid deadlines. The turnaround depends on the completeness of the documents. If we have the permit set, single-line diagram, and racking layout, we can start immediately. Missing information may require assumptions, which we document. For example, if the structural notes are missing, we may assume a standard attachment spacing and note it in the scope gap memo. We deliver in Excel and PDF, organized by CSI MasterFormat division, with marked-up plan sets.

Yes. Our PDF deliverable includes marked-up plan sets showing module counts, rail runs, conductor routes, and attachment locations. This helps your project manager trace each line item back to the drawing. We use Bluebeam Revu for markups, so the annotations are clear and professional. For example, we color-code DC and AC conduit runs and label each home run with its circuit number. We also mark trench lengths and equipment pad locations. This allows your field crew to verify quantities before installation.

We read the utility's interconnection manual and add items such as visible-break AC disconnect, production meter, and lockable box as separate line items. We also account for relay testing and witness tests if required. These items are often missing from the electrical bid, so we flag them in the scope gap memo. For example, some utilities require a manual disconnect within sight of the meter, while others require a lockable AC disconnect at the inverter. We also include the cost of utility coordination and any make-ready work.

Yes. For rooftop, we focus on attachment count, ballast TON, and roof penetrations. For ground-mount, we take off trenching, pile driving, and equipment pads. The racking type and foundation design drive the quantities. We adjust the takeoff based on the structural and civil sheets. For example, a ballasted rooftop system might require 1 attachment per 4 modules, while a penetrating system might require 1 per 2 modules. Ground-mount pile driving is measured in each, and we account for spoils removal and backfill.

We use Bluebeam Revu for plan markup and quantity extraction, PlanSwift for assemblies, and RSMeans data for ZIP-code-adjusted pricing. This combination allows us to produce accurate quantities and labor rates that reflect local market conditions. We deliver in Excel and PDF, organized by CSI MasterFormat division. For example, we can extract all conduit runs from the electrical plans using Bluebeam's measurement tools, then apply assemblies in PlanSwift to generate labor hours. RSMeans data ensures that our pricing matches the local market, adjusted by ZIP code.

We compare the structural notes to the attachment plan. If snow load or wind uplift requires closer attachment spacing, we re-takeoff the affected roof zones. This changes the attachment count and may require additional rail splices. We flag this in the scope gap memo so you can request a clarification from the structural engineer. For example, in high snow load areas, the attachment spacing might decrease from 4 ft to 2 ft on center, doubling the attachment count. We also check for wind uplift requirements that may require heavier rails or additional ballast.

Yes. We trace the communications pathway from the inverter to the network drop. This includes the monitoring gateway, current transformers (CTs), and network conduit. These items are frequently omitted from the electrical bid, so we add them as separate line items. This ensures your bid covers the complete system. For example, on a commercial rooftop, we include the cost of running Cat6 cable from the inverter to the building's network room, plus the gateway and CTs. We also account for any required revenue-grade metering.

We can take off only the Division 26 scope. This includes conductors, conduit, devices, and grounding. We separate what you own from what the GC owns, such as racking and civil work. This is common for electrical subcontractors. See our Subcontractor Estimating Services for more details. For example, we can provide a takeoff of all AC and DC electrical components, including inverters, combiners, and disconnects, while excluding modules and racking. This allows you to bid the electrical portion accurately.

A rooftop solar estimate typically covers module count, racking and ballast, roof curbs and flashing, DC homeruns, AC combiner and inverter terminations, conduit and cable tray, grounding, and monitoring. We take off from your structural drawing, electrical drawing, and single line diagram, then price labor by assembly with ZIP-code-adjusted rates. Deliverables are Excel and PDF with marked-up plan sets, organized by CSI division, so you can drop the line items into your bid form.

Interconnection and permit costs are jurisdiction-specific, so we list them as separate line items rather than burying them in the electrical assembly. We flag the interconnection study, permit fee, and any utility-specific metering or SCADA requirements shown on the drawings. Because adopted code editions and utility rules vary, confirm the current requirements with the local building department and the serving utility before you finalize your lump sum. We can also carry these as allowances if the AHJ has not issued the permit yet.

Yes. Ground-mount solar construction estimating adds civil and structural scope that rooftop work does not: pile or pier foundations, access road, erosion control, trenching, and medium-voltage collection. We take off fixed tilt, single axis, and dual axis racking separately, and we price DC and AC scope by division. We also flag GCR, shading, and soiling assumptions that affect performance and module layout. Confirm local code editions and environmental requirements with the AHJ before bid submission.

Photovoltaic estimating is the quantity takeoff and pricing of a solar array's DC and AC scope, from module count and string sizing to inverter and interconnection gear. It uses site data such as irradiance, peak sun hours, and azimuth to set production assumptions, then prices labor by manhour and material by unit price. The deliverable is a BOM, SOW, and cost breakdown you can bid from.