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gowith.solar

The map

Everything that goes into a solar or battery decision, and how the pieces connect. 119 concepts across 10 graphs, joined by 135 relationships.

The graphs cross into each other deliberately. A fact about your roof feeds a variable in the calculation, which feeds a number with a pound sign on it. Following those crossings is the whole exercise.

Decisions

The questions a homeowner is actually trying to answer, in the order they hit them. This graph, not the technology graph, is what the navigation and the learning tracks are built from.

  • Should I get solar at all

    feeds Solar or battery first, feeds Payback period.

  • Solar or battery first

    is fed by Should I get solar at all, feeds What size system.

  • What size system

    is fed by Solar or battery first, feeds What size battery, is fed by Add a heat pump.

  • What size battery

    is fed by What size system, feeds Which tariff to be on, is fed by Add a battery to existing solar.

  • Add a battery to existing solar

    feeds What size battery.

  • A battery without solar

    requires Time-of-use tariff.

  • Which tariff to be on

    is fed by What size battery, feeds Annual saving, is fed by How to charge an EV.

  • Cash or finance

    feeds Payback period.

  • Which installer

    feeds System cost.

  • Buy now or wait

    feeds System cost.

  • Add a heat pump

    feeds What size system.

  • How to charge an EV

    feeds Which tariff to be on.

The calculation

The model's own inputs and outputs, named. This graph is the site's differentiator: it lets an article point at the exact variable it is about, and it is why the content and the calculator are one product rather than two.

  • System size (kWp)

    feeds Annual generation, is fed by Usable roof area.

  • Annual generation

    is fed by System size (kWp), feeds Self-consumption rate, feeds Exported kWh, is reduced by Degradation, is fed by Roof orientation, is fed by Roof pitch, is reduced by Shading, is fed by Solar irradiance.

  • Self-consumption rate

    is fed by Annual generation, feeds Avoided import, reduces Exported kWh, is increased by Battery capacity, increases Annual saving, is fed by Occupancy pattern, is fed by Annual consumption.

  • Exported kWh

    is fed by Annual generation, is reduced by Self-consumption rate, feeds Export income.

  • Battery capacity

    increases Self-consumption rate, is reduced by Depth of discharge, is reduced by Round-trip efficiency, feeds Cost per usable kWh.

  • Depth of discharge

    reduces Battery capacity.

  • Round-trip efficiency

    reduces Battery capacity.

  • Cycle life

    feeds Battery replacement cost.

  • Degradation

    reduces Annual generation.

  • Projection horizon

    governs Payback period.

  • Avoided import

    is fed by Self-consumption rate, feeds Annual saving.

Money

Everything with a pound sign. This is the graph the site is actually about, and every article in every other graph should terminate somewhere in this one.

  • System cost

    is fed by Which installer, is fed by Buy now or wait, increases Payback period, is reduced by Grant, is reduced by Zero rate VAT, feeds Cost per kWp.

  • Cost per kWp

    is fed by System cost.

  • Cost per usable kWh

    is fed by Battery capacity, feeds Battery replacement cost.

  • Payback period

    is fed by Cash or finance, is fed by Should I get solar at all, is governed by Projection horizon, is increased by System cost, is reduced by Annual saving, is increased by Battery replacement cost.

  • Annual saving

    is fed by Which tariff to be on, is fed by Avoided import, reduces Payback period, is increased by Export income, is reduced by Maintenance cost, governs Today's money, is increased by Self-consumption rate, is fed by Import rate.

  • Export income

    is fed by Exported kWh, increases Annual saving, is fed by Export rate.

  • Grant

    reduces System cost, is fed by Boiler Upgrade Scheme, is fed by ECO4, offers Nest Wales.

  • Zero rate VAT

    reduces System cost.

  • Finance

    increases Opportunity cost, offers Home Energy Scotland loan.

  • Battery replacement cost

    is fed by Cycle life, increases Payback period, is fed by Cost per usable kWh.

  • Maintenance cost

    reduces Annual saving.

  • Property value

    is increased by Solar panel, is increased by EPC rating.

  • Opportunity cost

    is increased by Finance.

  • Today's money

    is governed by Annual saving.

Tariffs

The price of a kilowatt hour in each direction. A tariff change can move payback further than a hardware choice, and it is the one lever a homeowner can pull today for nothing.

  • Import rate

    feeds Annual saving, is governed by Energy price cap, is an alternative to Export rate, offers Utility Warehouse.

  • Export rate

    feeds Export income, is governed by Smart Export Guarantee, is an alternative to Import rate, offers Octopus Energy, offers British Gas, offers E.ON Next, offers EDF Energy, offers OVO Energy, offers Scottish Power, offers Good Energy, offers So Energy.

  • Standing charge

    is reduced by No standing charge tariff, is reduced by Warm Home Discount.

  • Energy price cap

    governs Import rate.

  • Smart Export Guarantee

    governs Export rate, requires Smart meter, requires MCS certification, is an alternative to Feed-in Tariff, is governed by MCS certification, is a source of variation in Northern Ireland.

  • Feed-in Tariff

    is an alternative to Smart Export Guarantee.

  • Time-of-use tariff

    is required by A battery without solar, pairs with Home battery, is an alternative to Economy 7, is an alternative to Fixed tariff, offers Octopus Energy.

  • Economy 7

    is an alternative to Time-of-use tariff.

  • EV tariff

    pairs with EV charger, offers Octopus Energy.

  • Heat pump tariff

    pairs with Heat pump, offers Octopus Energy.

  • Fixed tariff

    is an alternative to Time-of-use tariff.

  • No standing charge tariff

    reduces Standing charge.

Technology

The components of a home energy system and how they physically depend on each other. Drives 'what else do I need' linking.

  • Solar panel

    increases Property value, requires String inverter, is an alternative to Microinverter, pairs with Home battery, pairs with Solar diverter, pairs with EV charger, pairs with Heat pump, is an alternative to Solar roof tile, is an alternative to Plug-in solar, is fed by JinkoSolar, is fed by LONGi, is fed by Aiko, is governed by Planning permission, is governed by DNO G98 notification, is governed by Roof loading assessment.

  • String inverter

    is required by Solar panel, is an alternative to Hybrid inverter, pairs with Power optimiser.

  • Hybrid inverter

    is an alternative to String inverter, is required by Home battery, is fed by Sunsynk, is fed by SolaX, is fed by Growatt.

  • Microinverter

    is an alternative to Solar panel, is fed by Enphase.

  • Power optimiser

    pairs with String inverter, is fed by SolarEdge, is required by Shading.

  • Home battery

    pairs with Time-of-use tariff, requires Hybrid inverter, pairs with Solar panel, pairs with EV charger, is fed by Tesla Powerwall, is fed by GivEnergy, is fed by Pylontech, is fed by Fogstar, is fed by Fox ESS, is governed by DNO G99 application.

  • Solar diverter

    pairs with Solar panel, requires Immersion heater.

  • Immersion heater

    is required by Solar diverter.

  • EV charger

    pairs with EV tariff, pairs with Solar panel, pairs with Home battery, is fed by myenergi Zappi, is fed by Ohme, is governed by Building regulations.

  • Heat pump

    pairs with Heat pump tariff, pairs with Solar panel, is governed by Boiler Upgrade Scheme.

  • Smart meter

    is required by Smart Export Guarantee, is an alternative to Generation meter.

  • Generation meter

    is an alternative to Smart meter.

  • Solar roof tile

    is an alternative to Solar panel, is a source of variation in Roof type.

  • Plug-in solar

    is an alternative to Solar panel.

Products and brands

Named hardware people search for by brand. Brand queries are low difficulty and high intent, and each one is an opportunity to show the same payback maths on a specific product.

  • Tesla Powerwall

    feeds Home battery, is an alternative to GivEnergy.

  • GivEnergy

    feeds Home battery, is an alternative to Tesla Powerwall.

  • Sunsynk

    feeds Hybrid inverter, is an alternative to SolaX.

  • SolaX

    feeds Hybrid inverter, is an alternative to Sunsynk.

  • Pylontech

    feeds Home battery.

  • Fogstar

    feeds Home battery.

  • Growatt

    feeds Hybrid inverter.

  • Fox ESS

    feeds Home battery.

  • SolarEdge

    feeds Power optimiser.

  • Enphase

    feeds Microinverter.

  • JinkoSolar

    feeds Solar panel.

  • LONGi

    feeds Solar panel.

  • Aiko

    feeds Solar panel.

  • myenergi Zappi

    feeds EV charger.

  • Ohme

    feeds EV charger.

The property

Facts about a specific house that change the answer. These are the calculator's real inputs, and the reason a national average is useless to an individual.

  • Roof orientation

    feeds Annual generation.

  • Roof pitch

    feeds Annual generation.

  • Roof type

    varies by Solar roof tile.

  • Shading

    reduces Annual generation, requires Power optimiser.

  • Usable roof area

    feeds System size (kWp), is a source of variation in Property type.

  • Property type

    varies by Usable roof area.

  • EPC rating

    increases Property value, is increased by Insulation, is governed by EPC requirement.

  • Insulation

    increases EPC rating, is governed by ECO4.

  • Occupancy pattern

    feeds Self-consumption rate.

  • Annual consumption

    feeds Self-consumption rate.

  • Listed building

    requires Planning permission, requires Planning permission.

Regulation and schemes

The rules that decide whether something is allowed and whether it is paid for. Regulation articles date fastest, so each one carries the date it was checked.

  • MCS certification

    is required by Smart Export Guarantee, governs Smart Export Guarantee.

  • Planning permission

    is required by Listed building, governs Solar panel, is required by Listed building.

  • Building regulations

    governs EV charger.

  • DNO G98 notification

    governs Solar panel.

  • DNO G99 application

    governs Home battery.

  • Boiler Upgrade Scheme

    governs Heat pump, feeds Grant.

  • ECO4

    governs Insulation, feeds Grant, pairs with Warm Home Discount.

  • Warm Home Discount

    reduces Standing charge, pairs with ECO4.

  • EPC requirement

    governs EPC rating.

  • Roof loading assessment

    governs Solar panel.

Suppliers

Who offers which tariff and which export rate. Supplier queries are high volume and low difficulty, and are the natural place to compare a real rate against the alternatives.

  • Octopus Energy

    is offered by Time-of-use tariff, is offered by Export rate, is offered by EV tariff, is offered by Heat pump tariff.

  • British Gas

    is offered by Export rate.

  • E.ON Next

    is offered by Export rate.

  • EDF Energy

    is offered by Export rate.

  • OVO Energy

    is offered by Export rate.

  • Scottish Power

    is offered by Export rate.

  • Good Energy

    is offered by Export rate.

  • Utility Warehouse

    is offered by Import rate.

  • So Energy

    is offered by Export rate.

Geography

Where the house is, which changes both generation and the schemes available. Irradiance varies by roughly a fifth across the UK, which is enough to move payback by years.

  • England

    varies by Solar irradiance.

  • Scotland

    varies by Solar irradiance.

  • Wales

    varies by Solar irradiance.

  • Northern Ireland

    varies by Solar irradiance, varies by Smart Export Guarantee.

  • Solar irradiance

    feeds Annual generation, is a source of variation in England, is a source of variation in Scotland, is a source of variation in Wales, is a source of variation in Northern Ireland, is a source of variation in South East England, is a source of variation in South West England, is a source of variation in Northern England, is a source of variation in The Midlands.

  • South East England

    varies by Solar irradiance.

  • South West England

    varies by Solar irradiance.

  • Northern England

    varies by Solar irradiance.

  • The Midlands

    varies by Solar irradiance.

  • Home Energy Scotland loan

    is offered by Finance.

  • Nest Wales

    is offered by Grant.