Smart Meter: Before or After Solar?

The right order matters. Get the smart meter first and you'll have baseline data and export capability from day one.

Smart Meter First. Always.

The short answer: get your smart meter installed before your plug-in solar panels arrive. Here's why the order matters.

Reason 1: Baseline Data

A smart meter records your half-hourly consumption. If you install it before solar, you get a clean record of what your household uses without solar. This baseline is invaluable for:

Measuring actual savings — compare pre-solar import to post-solar import (how to do this)
Calculating self-consumption — you need to know your typical daytime usage to estimate how much solar you'll use directly vs export
Choosing the right system size — if your baseline daytime usage is 400W average, an 800W system will export a lot; a 400W system might be more cost-effective without a battery

Even two weeks of baseline data is useful. A month is ideal.

Reason 2: Export Register Ready from Day One

If you install solar before getting a smart meter, any surplus you export to the grid goes unrecorded. You can't apply for SEG payments without a smart meter, and you're losing export data that you'll never get back.

With the smart meter in first and the export register enabled, every kWh you export from the moment you plug in is recorded and payable.

Reason 3: Avoiding the SMETS1 Confusion

If your property already has a SMETS1 meter and you install solar first, you might encounter odd readings or errors when your panels start exporting. This causes unnecessary worry and a phone call to your supplier. Better to upgrade to SMETS2 in advance and avoid the issue entirely.

The Practical Timeline

Here's the recommended sequence:

Week 1: Order your smart meter installation from your supplier. Typical wait: 2–4 weeks.

Week 2–3: While waiting, research and order your plug-in solar kit. Use the panel finder quiz to get a recommendation.

Week 3–4: Smart meter installed. Start collecting baseline data.

Week 5+: Plug-in solar kit arrives. Install it. Contact your supplier to enable the export register (if not already active) and apply for SEG.

Week 6: Notify your DNO (required within 28 days of installation).

This sequencing means everything is ready when your panels start generating. No lost data, no configuration scrambles.

What If Solar Is Already Installed?

If you've already got plug-in solar running on a non-smart or SMETS1 meter, it's not too late:

Request a SMETS2 installation immediately
Once installed, ask for the export register to be enabled
Apply for SEG — you can't claim for past un-metered exports, but future exports will be recorded
Start using the half-hourly data to optimise self-consumption

You've missed some export data and baseline comparison, but the ongoing benefits are the same.

The full sequenced checklist

If you are starting from zero and want to do this in the "right" order for maximum clean data and minimum admin friction:

Book the SMETS2 installation — call your supplier, request smart meter. Typical wait: 2–4 weeks. Free.
Two weeks of baseline data — let the meter record your normal consumption pattern before solar arrives. This becomes your "before" comparison for checking savings.
Confirm the export register is enabled — some suppliers activate it automatically on install; others need a phone call. See how to enable your export register.
Order and install the solar kit — takes 1–2 hours for a garden or balcony install. See how to install plug-in solar.
File the G98 notification with your DNO within 28 days of energising. See G98 step-by-step. Free and takes 10 minutes online.
Notify your home insurer — one-line email, template in the insurance notification guide.
Apply for SEG with your chosen export supplier (does not have to match your import supplier). See the SEG rate table for current rates.
Start monthly self-consumption tracking — first Sunday of each month, note export register reading vs generation. See self-consumption tips.

Total elapsed time: 4–6 weeks from booking the meter to first SEG payment. Total admin time: under 90 minutes across the whole sequence.

What breaks the sequence (and how to salvage)

Common failure modes when the order gets scrambled:

Solar installed before smart meter. No SEG data, no half-hourly optimisation possible. Fix: book SMETS2 now, accept that you have lost 1–3 months of export payments (typically £2–£12 lost), then follow steps 3–8.
SMETS2 installed but engineer skipped export register. Common. You will see import data in the app but no export. Call supplier, ask for "export register activation with HHS settlement enabled". Usually done within 24 hours remotely.
DNO notification filed but not connected to supplier record. Some suppliers refuse SEG applications until they can see the DNO notification. Fix: include a copy of your G98 confirmation email in the SEG application form.
SEG supplier does not match import supplier. Fine — this is legal and often preferable. But confirm the export MPAN is correctly registered with your chosen SEG supplier or payments will not appear.