Solar Tool · Rooftop solar estimator

1. Find the property

Address

2. Solar potential

Occupancy archetype

MCS 032 Table 2. Where occupancy is unknown the standard directs you to “in half the day”.

Shade factor (SF)

1.00 only where the horizon is clear.

System size

Battery storage

Share allocated to solar self-consumption (%)

MCS 032 §4.4. The remainder is treated as other services — backup or arbitrage — discharging at the §4.3 limit of 730 cycles a year.

Assumptions used in the money figures

Panel rating (W)

Your annual use (kWh)

Import price (p/kWh)

Export rate (p/kWh)

Used on site (%)

Install cost (£/kWp)

Grid carbon (g/kWh)

Battery

Battery cost (£/kWh)

Off-peak import (p/kWh)

Usable capacity (%)

Round trip (%)

Days active (%)

Warranty (years)

Battery cost is suggested from the capacity you pick and falls with scale; overwrite it with a real quote. Off-peak import is the cheap overnight rate the battery charges at — set it equal to your import price if you are not on a time-of-use tariff, and grid arbitrage drops out.

Google returns DC output. We apply an 85% DC→AC derate for inverter and system losses, then split generation between on-site use and export.

MCS 032 performance estimate (Table 5)

Roof breakdown

Face	Direction	Pitch	Area	Sun

3. Suggested panel layout

Enter a postcode and choose an address to see the roof.

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