Energy Plan

Most solar calculators ask you for an abstract “annual kWh.” WireSketch already knows what’s on your walls. The Energy Plan turns your placed fixtures into a household load profile, matches that against your solar yield by season, and gives you three honest numbers: how much of your solar gets used onsite, how many days of outage autonomy your battery would actually cover, and a simple payback estimate for the system.

What it is, and where it lives

The Energy Plan sits at Home level, not project level — because your fridge, heat pump, and EV are properties of the dwelling, not of any particular renovation. One plan per home, shared across every project under it. You reach it two ways:

• From the Home detail view, as a top-level section between Panels and Projects.
• From the Solar Summary sheet inside any solar project attached to that home.

Both routes open the same sheet, persist to the same storage, and mutations from one are visible from the other.

Auto-seed from your placed fixtures

The unique angle. When you open the Energy Plan for the first time, WireSketch reads every fixture you’ve placed across every wall of every project in this home and offers to pre-fill the device list with realistic defaults:

• EV Charger → Electric Vehicle, 7.4 kW × 1.5 h/day (about 4 000 km/year)
• Oven Connection → Electric Oven, 2.5 kW × 0.5 h/day, 5 days/week
• Dishwasher Connection → Dishwasher, 1.8 kW × 1 h/day, 5 days/week
• Washer Connection → Washing Machine, 2.2 kW × 1 h/day, 4 days/week
• Fridge Connection → Fridge, 100 W × 24 h/day (always on)
• Floor Heating Thermostat → Electric Floor Heating, 1.5 kW × 6 h/day, winter only
• Router → Router + network, 12 W × 24 h/day

Defaults aim at honest middle-of-the-road EU residential averages, not nameplate maximums. A 2 200 W washer runs at full power for ~20 minutes of a 1-hour cycle — we tune watts to the realistic average. You can tap any device to override.

For appliances that aren’t represented as fixtures (heat pump, AC, induction hob, tumble dryer, pool pump, dehumidifier, kettle, lighting, electronics), tap Add from library — the preset catalog covers 18 common residential loads with sensible defaults.

Mode 1: Self-consumption

The default landing. Two headline numbers:

• Coverage % — annual PV yield divided by annual consumption, capped at 100%. Tells you whether your roof is big enough.
• Self-consumption % — of all the kWh your panels produce, what share gets used onsite vs exported to the grid. The honest headline.

These can be wildly different. A 12 kWp roof on a 5 MWh home shows 100% coverage but only ~25% self-consumption — you produce more than you use, but the extra goes to the grid because you can’t store it. A 4 kWp roof on the same home shows ~75% coverage and ~45% self-consumption — less surplus.

The seasonal breakdown shows the same two ratios for summer vs winter separately. This is where electric-heating homes hit reality: 90% coverage in summer, 15% in winter, because PV peak and heating peak are six months apart.

When no battery is in the project, the sheet adds a what-if line: “Adding a 10 kWh battery could lift self-consumption to about 75%.” Sized using a smoothly-saturating model that caps the uplift when the battery reaches ~half daily consumption.

Mode 2: Resilience (outage autonomy)

Toggle the segmented control at the top of the sheet to switch into resilience mode. The question changes from “how much will I use?” to “how long will my battery last in a blackout?”

Each device carries a criticality tag: Critical, Comfort, or Luxury. The auto-seed sets sensible defaults — fridge, router, lighting, and winter heating are critical; oven, washer, and electronics are comfort; EV charging, AC, dryer, and pool pump are luxury. Override per device.

The autonomy calculation:

• Sum the daily kWh of every enabled device tagged Critical (and optionally Comfort, if you toggle the “Critical + Comfort” scope).
• Add the always-on baseline (default 80 W — standby loads, smart-home gear, modem, smoke alarms).
• Take 90% of the nameplate battery capacity — modern LFP usable depth of discharge. Older lithium and lead-acid batteries deliver 50–70%.
• Divide. The result is days of autonomy on battery alone.

The headline shows a verdict colour-coded by autonomy days: insufficient (<0.5d), marginal (0.5–1d), adequate (1–3d), strong (3–7d), excellent (>7d). A daily-energy breakdown shows where the load comes from (devices vs baseline). A target-days stepper recommends a battery size — “For 3-day autonomy you’d need a 20 kWh battery.”

Mode 3: Solar ROI (payback)

A third tab estimates when the system pays for itself. It values the energy you self-consume at your electricity price, adds any exported surplus at your feed-in rate, and divides the system cost by that annual benefit to give a simple payback in years.

Enter your own electricity price, feed-in tariff, and total system cost — or let WireSketch fall back to region-aware price defaults and a per-kWp cost estimate (clearly labelled as an estimate, with a one-tap reset). It is deliberately a simple-payback model: no time-of-use rates, no feed-in escalation, no inflation, no financing, no degradation curve. A first-order “is this worth it?” check, not a financial product.

Plug-in solar packages

No roof to draw? Add a plug-in package directly: a balcony solar kit (Balkonkraftwerk), the same kit with a small battery, or a battery on its own. Each carries a pre-set capacity and a typical regional price and feeds straight into the self-consumption, resilience, and payback numbers — so a renter or balcony owner can size and sanity-check a system without ever drawing a roof.

Honest framing

The sheet has a How we estimate button that opens a disclosure listing every assumption: the latitude-aware seasonal split (60–80% summer share depending on where you are), the EU-anchored self-consumption curve, the 90% battery DoD model, the cold-weather derating caveat, and the not-hourly-simulation note. Nothing hidden.

The preset library

18 common residential devices with realistic defaults and sensible default criticality:

• Heavy continuous loads: Heat pump, Electric heating, Air conditioner, Electric vehicle
• Always-on background: Fridge, Freezer, Router
• Big appliances: Oven, Induction hob, Cooker hood, Dishwasher, Washing machine, Tumble dryer
• Lighting + electronics: Lighting, Electronics (TV + console + laptop)
• Outdoor + seasonal: Pool pump, Dehumidifier, Electric kettle

Each preset carries a name, default watts, default hours/day, default days/week, default season, default criticality, and an SF Symbol icon. Translated into all 9 supported languages.

What it isn’t

• Not an hourly simulator. Annual model with seasonal-half splits. Off by ±15–20 percentage points in either direction.
• Not a full financial model. The optional payback estimate is a simple payback from your electricity price and an estimated or entered system cost. It does not model time-of-use rates, feed-in escalation, inflation, financing, or panel degradation — and pricing varies enormously by market and regulator. Treat the figure as a rough estimate.
• Not a smart-meter import. No CSV upload, no API ingestion. The plan is what you enumerate.
• Not a compliance document. A licensed electrician designs the actual install; the Energy Plan is a sizing and conversation aid.

Pro feature

The Energy Plan is part of the Solar Planner unlock — one-time purchase, no subscription. Free tier users see Homes and the planner; the Energy Plan is in the Solar Planner bundle.