An air source heat pump beside a brick house, planting around it

Planning for what’s next

A car or heat pump changes the system we size.

An electric car or a heat pump changes how much power the house uses, and when. Tell us before your survey and the array, the inverter and the battery question are all weighed with them in mind.

Get my estimate Where spare power goes
Takes power first
The house
When to tell us
Before the survey
Order after the house
Yours to choose

Why it matters

Why we ask before we size.

Your estimate starts from your bill, because the bill says how much power the house uses. An electric car or a heat pump changes that: either can add as much again, so last year’s bill can understate what the house will need.

Solar with a car or heat pump
A wall-mounted car charger showing 17.3 kWh, its cable plugged in

Electric car · heat pump · hot water

Planning a car or a heat pump? Tell us first.

Either can use as much power as the rest of the house, and at different times of day. Knowing now changes the array we size, the inverter we choose and whether a battery earns its place.

Your roofWhat the array makes

  1. The house · firstWhatever is running takes the roof’s power first.
  2. BatteryStores what’s spare for the evening.
  3. Hot waterA diverter sends spare power to the immersion heater.
  4. The grid · what’s leftExported, and paid at your export rate.
  5. Electric carA charger that follows the sun tops up on spare power, or charges overnight on a cheaper rate.
  6. Heat pumpWorks hardest in winter, when the roof makes least, so we size for the house you’ll have, not the bill you had.

After the house, you choose the order.

Plan it into your estimate

Tell us now

What to mention, and what it can change.

Mention them when you ask for an estimate or book your survey. The surveyor then checks the consumer unit, the meter and where a battery could live, with your plans in mind.

Tell us if you’re planning

  • An electric car, or another one
  • A heat pump
  • Hot water heated by spare power
  • A battery, now or later

What it can change

  • More panels, if the roof has room for them
  • An inverter sized with the extra load in mind
  • The battery sums, if the car charges overnight
  • Room in the consumer unit for what comes next

Chargers that follow the sun

Car, heat pump and hot water · questions

Asked about what’s next.

01Can I add a charger or heat pump later?

Yes. Telling us now means the inverter we choose can allow for it, and there is room left for what comes next.

02Will solar run my heat pump in winter?

Not on its own. A heat pump works hardest in winter, when the roof makes least, so it still relies on the grid through the colder months.

03What is a diverter?

A device that sends spare power from the roof to your immersion heater, so it heats water instead of being exported.

04Does a car make a battery worth it?

It can. A car that charges overnight is one of the times a battery is usually worth it, and your estimate is priced both ways so you can see.

Every question

From the guides

Read more before you decide.

Every guide explains one part of the job in plain English.

A quiet street of terraced houses with front gardens

Money · 5 min read

Export payments, in plain English

How the Smart Export Guarantee works, what has to be in place before payments start, and why part of a solar saving is export income.

Read the guide

Keep reading

The rest of the service.

A bungalow with a panelled roof across an evening field

Estimate or survey

Start with a postcode.

Our estimate is free. If you proceed to survey, our partner installer invoices you directly; we receive a referral fee from them, never from you, and it never affects which installer we introduce.

We use these details only to send your estimate and arrange a survey. Privacy Policy

This form needs JavaScript switched on.

Or ring us free on 0800 593 0413