- Most homes now have digital or smart meters that record imports and exports separately. They do not run backwards.
- Old electromechanical meters can spin backwards when you export, which some utilities treat as a problem.
- Under most plug-in laws, exports are not credited. The savings come from using your own power.
- In Germany, old backward-running meters are tolerated temporarily until replaced.
It is the first thing many people imagine: you plug in a solar panel and watch the meter wheel turn the wrong way. In reality, what happens depends on the meter hanging on your wall.
In this article
Three types of meter
| Meter type | What happens when you export |
|---|---|
| Smart meter (two-way) | Records import and export in separate registers. Your bill charges imports; exports are only paid if you are on an export plan. |
| Digital meter without export register | Most count only imports; exports are simply not recorded (and not paid). |
| Old electromechanical (spinning disc) | The disc can turn backwards, effectively crediting you at the full retail rate. |
Why backwards-spinning is complicated
A meter that runs backwards gives you full retail value for every exported kWh, which is more generous than most net metering schemes. Utilities do not like that, and some tariffs forbid it. That is part of why plug-in laws in the US explicitly exclude these devices from net metering. If you have an old meter and export a lot, your utility may replace it with a digital one when they notice.
Germany handled this pragmatically: since the 2024 Solarpaket I reforms, a balcony system can be used while the old meter is still installed, and the grid operator replaces it in due course. In the UK, most homes either have smart meters or digital meters with a separate export register.
What matters for your savings
Since exports are usually worth nothing, what counts is self-consumption: the share of solar power your home uses while it is being produced. A typical apartment uses 100-300 W continuously for the fridge, router, standby devices and so on. An 800 W kit on a sunny day will exceed that around midday and export the surplus.
- Run dishwashers, washing machines and dryers in the middle of the day.
- Charge laptops, e-bikes and tools while the sun is up.
- Consider a battery if you routinely export a lot. See do you need a battery?
We go deeper in how self-consumption affects your savings.
Can I set the kit to never export?
Yes, with extra hardware. A “zero-export” setup uses a meter reader or smart meter integration to throttle the inverter or charge a battery so that nothing flows to the grid. It is mainly useful where exporting is not allowed or where you want to maximize a battery. See zero-export settings explained.
Should I tell my utility?
If your state or country requires notification, yes. In US states like Virginia or Maryland, the notification exists partly so the utility knows about the device in case your meter needs attention. See the law tracker for your state’s rules.
How to tell which meter you have
- A spinning aluminum disc behind glass: an old electromechanical meter.
- A digital display with a single reading: a digital meter that may or may not record export.
- A display that cycles through several registers (often labeled import/export or codes such as 1.8.0 and 2.8.0 in Europe): a two-way meter.
- A utility app with hourly data: almost certainly a smart meter.
Frequently asked questions
Is it illegal for my meter to run backwards?
It depends on your utility’s tariff and local rules. Plug-in laws in the US generally exclude these devices from net metering, and utilities may replace old meters. In Germany, it is tolerated until the grid operator swaps the meter.
Will my utility notice my kit?
With a smart meter, your daytime consumption drops and small exports may appear. In states requiring notification, the utility already knows. That is normal and expected.
Can I get a meter that pays me for exports?
Only if your utility offers an export tariff that applies to plug-in devices, which is rare. In the UK, watch for changes to the Smart Export Guarantee.
Sources
- H.B. 340 Solar Power Amendments (2025 General Session), Utah State Legislature.
- SB 250, 2026 Regular Session, Virginia Legislative Information System.
- Marktstammdatenregister, Bundesnetzagentur.
- Smart Export Guarantee (SEG), Ofgem.
Sources checked in September 2026. Laws, prices and product details change; if you spot something out of date, tell us.