How to Add Your Smart Meter Readings: Bright Sync and CSV Upload

Everything on Heat Pump Tariffs is built on one thing: your actual half-hourly smart meter readings. Instead of guessing your usage from an annual figure, the site scores every tariff against the real pattern of when and how much electricity you use — which matters enormously for heat pump and EV households, where when you draw power changes the bill dramatically.

So before you can compare anything, you need your readings in. There are two ways to do that, and this guide covers both: connecting the Bright app for automatic nightly syncing, or doing a one-off CSV upload. Most people start with one and never need the other, so pick whichever fits.

Option 1: Connect Bright (automatic syncing)

What it is

Bright is a free smart meter app from Hildebrand that reads your half-hourly data straight from the national meter network. Once you connect your Bright account to Heat Pump Tariffs, your readings sync automatically each night — no files, no manual steps. This is the route to choose if you want a "set it and forget it" setup.

You'll need the Bright app installed and your meter showing data in it first. If you don't have it yet, install Bright (by Hildebrand) on your phone, register, and give it a day or two to start pulling readings before connecting here.

How to connect

The setup is a short four-step wizard. Go to Bright Smart Meter Connection and you'll see a progress bar: Sign in → Property → Meter → Comparisons.

1. Sign in. Enter the username (your email) and password you use for the Bright app. These connect to the Glowmarkt API to fetch your data. There's an option to remember your password so syncing keeps working without re-entering it — more on that below.
2. Property. If your Bright account has more than one property, pick the one with the meter you want. If you only have one, this step is skipped automatically.
3. Meter. Choose the electricity meter to sync (again, skipped if there's only one).
4. Comparisons. Finally, set whether you'd like automatic weekly and monthly comparisons. These are switched on by default so you start getting results without lifting a finger.

That's it — you'll see a confirmation, and your readings will sync each night from then on.

Worked example

A typical first connection looks like this: install Bright, register with you@example.com, wait until the app shows yesterday's usage, then come here, sign in with those same details, accept the single property and single meter that appear, leave the comparison toggles on, and finish. The next morning your dashboard shows your first synced readings and an initial comparison.

Common mistakes

• Connecting before Bright has data. If the Bright app itself isn't showing readings yet, there's nothing for us to sync. Get Bright working first, then connect.
• Forgetting the connection expires. If you don't tick "remember my password", the Bright connection needs refreshing roughly every seven days — you'll be asked to re-enter your password when it lapses. Ticking the box lets syncing renew itself automatically. You can also turn on failure notifications so you get a single email if syncing ever stops.
• Too many sign-in attempts. To protect your Glowmarkt account from being locked, sign-in is limited to five attempts every fifteen minutes. If you hit that, just wait the few minutes shown and try again — double-check your Bright password in the app first.

Option 2: Upload a CSV (manual import)

What it is

If you'd rather not connect an account, or your data comes from somewhere Bright doesn't cover, you can upload a CSV of your half-hourly readings directly. This is ideal for a one-off import or for topping up a specific date range.

The uploader recognises four common formats automatically, so in most cases you just choose your file and it works out the rest:

• Standard smart meter export
• Octopus Energy export
• n3rgy / Glowmarkt portal export
• A plain datetime format (where it will ask one extra question — see below)

How to upload

1. Export your half-hourly data from your supplier or energy portal as a CSV. (Octopus, EDF, n3rgy and the Glowmarkt portal all offer this — look for "half-hourly" or "30-minute" consumption data.)
2. On the Upload page, select your CSV file.
3. The format is detected automatically. If the file is recognised, it's imported immediately and you're taken straight to a comparison.
4. If the format can't be identified, you'll be asked to pick it from a list. If you choose the plain datetime format, you'll also be asked whether the times are in UTC/GMT or UK local time — this matters, so answer carefully (see mistakes below).

Worked example

Say you download a half-hourly CSV from your Octopus account covering the last three months. You select it on the Upload page, the system detects "Octopus Energy format", imports it, tells you how many new slots were added (and quietly skips any duplicates you'd already uploaded), and drops you onto a comparison for that data. Done in one step.

Common mistakes

• Choosing the wrong timezone on an ambiguous file. When the uploader asks UTC vs UK local, picking wrong shifts every reading by up to an hour. That throws off which half-hour slot each reading lands in — and for time-of-use tariffs, the slot is everything. If your export came from a UK energy portal, it's usually UK local time; if you're unsure, check whether the file's overnight timestamps line up with your cheap-rate window.
• Files that are too big. There are limits on file size, number of rows, and how many days a single file can span. If your export is rejected for being too large, split it into smaller date ranges and upload them one at a time — duplicates are skipped automatically, so overlapping ranges are harmless.
• Very old readings being skipped. Readings before the site's minimum date are ignored on import. If your row count comes in lower than expected, that's usually why — the message will tell you how many were skipped.
• Hitting the upload allowance. There are per-hour, per-day and per-week upload limits (Bright auto-syncs don't count against these). The Upload page shows your remaining allowance, so you can see at a glance how many you have left.

After your readings are in

Whichever route you took, head to My Readings to see what you've got. Each upload shows its date range and a coverage bar, with badges for the important stuff:

• Full coverage — every day in the range has readings. Ideal.
• Missing days — gaps where no data exists. If you have a Bright connection, there's a one-click button to fill these from Bright.
• Partial days — days with fewer than the full set of half-hourly slots, usually from a brief API or meter outage. These can also be topped up from Bright, or by uploading a CSV for those dates.

Good coverage matters because a comparison is only as accurate as the data behind it: a month with missing days will understate your usage and flatter every tariff equally, which muddies the ranking.

Once you're happy with your coverage, run a comparison — and you'll see exactly what every tariff in your region would have cost you against your own real usage.