Every solo installer hits the same wall eventually. The PV layout lives in Aurora Solar or Helioscope. The battery sizing lives in a spreadsheet. The heat pump load calculation lives in another spreadsheet, or worse, the installer’s head. The electrical schematic gets redrawn in AutoCAD. The permit PDF is hand-assembled from five sources. For one project this is annoying. For 5–15 projects per month it is a tax of 90–150 minutes per job.
This guide covers the alternative: multi-discipline solar design — producing solar, battery, heat pump, electrical, plumbing and structural drawings as one coordinated CAD deliverable. We compare the five tools that touch this space, walk through the eight-step workflow, and analyse the price math (lifetime versus subscription) for a typical residential installer.
Multi-discipline solar design is the practice of producing solar, battery, heat-pump, electrical, plumbing and structural drawings as a single coordinated CAD deliverable, rather than handing those disciplines off to separate tools, licenses or contractors. The output is a permit-ready package that covers the full energy installation — not just the PV layout.
The discipline is not new. Architecture, engineering and construction (AEC) firms have used integrated CAD for buildings for decades — Revit and AutoCAD MEP coordinate plumbing, electrical and HVAC across one model. What is new is that the same approach has reached residential-scale solar, because the energy installation itself has become multi-discipline: 5 years ago a PV project was just panels and an inverter. In 2026 it is panels + battery + EV charger + heat pump + smart-meter integration.
The International Energy Agency reported that residential heat pump sales grew faster than solar PV in EU markets in 2024-2025 — meaning the "complete energy installer" persona is now the dominant buyer, not the pure PV installer. CAD tools that only handle PV are increasingly mismatched with how installers actually work.
A solo installer doing 5–15 residential projects per month operates under three constraints that single-discipline tools ignore:
Aurora Solar costs $156/month — $9,360 over 5 years per seat. Helioscope starts at $79/month. Add a separate battery sizing tool, a heat pump load calculator, and an electrical CAD license, and the subscription stack hits $3,000–5,000/year per seat. For an installer netting €2,000 per residential job, the tool stack eats 5–10% of revenue on the smallest jobs.
Single-discipline workflow looks like this: design PV in Tool A, export, redraw the electrical single-line in Tool B (typically AutoCAD), copy battery sizing from Tool C, assemble PDF manually, send to the permitting authority. Typical residential project: 90–150 minutes from sketch to submitted permit. Multi-discipline workflow in one tool: 15–45 minutes, because the schematic and BOM auto-generate from the same source model.
When the PV layout changes in Tool A, the SLD in Tool B does not update automatically. The installer manually re-checks the breaker sizing, the inverter rating, the BOM. In a busy week this slips, and a customer ends up with mismatched documentation. Multi-discipline tools eliminate this drift by holding all disciplines in one model with shared parameters.
Not every project needs every discipline. A pure rooftop PV with a string inverter and no battery is a 1-discipline job. A "complete energy" installation can touch 6–9 disciplines. Here is the full taxonomy and which tool handles each well.
| Discipline | Diaz Editor | Aurora Solar | Helioscope | OpenSolar | PVsyst | SketchUp + Skelion |
|---|---|---|---|---|---|---|
| 3D building model | Yes | Limited | Limited | Limited | No | Yes |
| 2D CAD drafting | Yes | No | No | No | No | Yes |
| Solar PV layout | Yes | Yes (best-in-class) | Yes (best-in-class) | Yes | Yes | Yes (via Skelion) |
| Battery sizing | Yes | Limited | Limited | Limited | Yes | No |
| Heat pump integration | Yes | No | No | No | No | No |
| Electrical schematic (SLD) | Yes | Limited | Add-on | Limited | No | No |
| Plumbing layout | Yes | No | No | No | No | Manual |
| HVAC ducting | Yes | No | No | No | No | Manual |
| Permit-pack PDF auto-gen | Yes | Yes | Yes | Yes | Limited | Manual |
The pattern is consistent: Aurora, Helioscope, OpenSolar and PVsyst all excel inside the PV discipline and stop at its edge. SketchUp covers more disciplines but requires plugin licensing per discipline, and the workflow is stitched together rather than coordinated. Diaz Editor was purpose-built for multi-discipline residential coverage — see the head-to-head comparisons at vs Aurora, vs Helioscope, vs OpenSolar, vs PVsyst and vs SketchUp + Skelion.
Two patterns dominate the market. Solar-only tools (Aurora, Helioscope, PVsyst, OpenSolar) are deep within PV but require additional tools or manual work for adjacent disciplines. Multi-discipline tools (Diaz Editor, SketchUp + plugins, full Revit/AutoCAD MEP setups) cover the breadth but at varying depth per discipline.
Below is the eight-step workflow we use for a typical 7 kWp + 10 kWh + heat pump residential project. Total time end-to-end: 45 minutes for an experienced operator. The same sequence in a single-discipline workflow would take 90–150 minutes.
The Diaz Editor first-project tutorial walks through a condensed version of this workflow in 15 minutes — see /help/first-project for the step-by-step. The National Renewable Energy Laboratory publishes reference workflows for PV sizing that complement the multi-discipline steps above.
Here is the five-year cost math for an installer who covers solar, battery, heat pump and electrical disciplines. Numbers reflect current published pricing for one seat.
| Stack | Per-month | 5-year cost | Multi-discipline? |
|---|---|---|---|
| Aurora Solar (PV only) + add-ons | $156 + $40 + $60 + $25 = $281 | ~$16,860 | Yes (via stack) |
| Helioscope + add-ons | $79 + $40 + $60 + $25 = $204 | ~$12,240 | Yes (via stack) |
| OpenSolar (PV only) + transaction fees | Free + ~$8/proposal × 10 = $80 | ~$4,800 (varies) | No (PV only) |
| SketchUp Studio + Skelion + Layout | $749/yr + $290/yr = ~$87/mo | ~$5,200 | Partial |
| PVsyst Premium | ~$62/mo (annual) | ~$3,720 | No (yield-only) |
| Diaz Editor Founding | One-time €99 | ~€99 | Yes (9 disciplines) |
| Diaz Editor Pro (regular) | One-time €999 | ~€999 | Yes (9 disciplines, 3 seats) |
Two caveats. First, the $281/mo add-on stack is the worst case for full multi-discipline coverage with Aurora — many solo installers skip the heat pump and electrical tools and accept manual rework to lower the bill. Second, lifetime pricing assumes the vendor continues to ship updates; the Diaz Editor bus-factor protection via the MIT-licensed Pascal Editor base is the trust-anchor that makes a multi-year lifetime commitment sane.
A solo installer who spends $3,000/year on a subscription stack and switches to a €999 lifetime multi-discipline tool breaks even in 4 months. At the founding price of €99, break-even is under 2 weeks of saved subscription fees. The harder math is opportunity cost: how many extra projects per month can you take if each one is 60–90 minutes faster end-to-end? At a conservative €500 net margin per residential project, an extra project per week is €26,000/year in marginal revenue — an order of magnitude more than the tooling savings.
From 1 January 2027, the Dutch salderingsregeling stops — feed-in to the grid is no longer netted against consumption at the retail tariff. Battery sizing becomes the dominant economic driver of every Dutch residential PV project, because self-consumption is now the only way to capture the full value of generated kWh.
Multi-discipline tools handle this transition naturally: the battery is part of the same model as the PV array, sized against the household load curve, with self-consumption and feed-in modes computed in the same simulation. Single-discipline PV tools that treat the battery as an afterthought will lose Dutch market relevance fast.
For a deep-dive on this specific transition, see the Dutch-language pillar: Solar design software voor Nederlandse installateurs. For the Spanish-market equivalent under RD 244/2019 self-consumption rules, see Software de diseño solar para instaladores en España.
For projects up to roughly 30 kWp PV plus a 30 kWh battery and a residential heat pump, yes — Diaz Editor and SketchUp + Skelion are both capable. For utility-scale PV (10 MW+) or NEM 3.0 financial pro-formas you still need Aurora or Helioscope. For deep yield-loss simulation, PVsyst remains the academic standard.
No direct project import yet. You can export panel layouts as DXF or PDF from Aurora or Helioscope and re-create the system in 5–15 minutes for a typical residential project. The roof traces are usually the longest part — built-in roof tools speed this up. A bulk migration utility is on the v0.5 roadmap; see the public roadmap for the latest schedule.
Multi-discipline tools have made different bets. OpenSolar is cloud-only with built-in collaboration. Diaz Editor is local-first by design — files stay on the installer's machine, no cloud account is required, no per-seat collaboration fees. Real-time multi-user editing is planned for v0.7+ using CRDT-based sync, opt-in only.
Three options. 1. Try the founding-beta tier — €99 lifetime, 100 spots, full multi-discipline coverage, 14-day satisfaction waiver. 2. Read the comparisons — vs Aurora, vs Helioscope, vs OpenSolar, vs PVsyst and vs SketchUp + Skelion to see whether the fit is right. 3. Walk through the eight-step workflow via /help/first-project before committing.
Published 2026-05-13 by Juan Diaz, founder of Diaz Atlas and current maintainer of Pascal Editor (the MIT-licensed CAD engine Diaz Editor is built on). This guide is opinionated — honest comparisons are at /vs/aurora-solar and related pages.
One-time. Lifetime. 3 seats. No subscription.
Built for self-employed tradespeople + small teams (1-10 people). Not for architects or utility-scale engineering — AutoCAD and Aurora are better at those.
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