HH Meter Data
Half-Hourly Meter Data for Solar Sizing
The single most important data input for an accurate commercial solar quote is your half-hourly (HH) meter data. Below is what HH data is, how to get it, and how it transforms solar sizing accuracy.
48 readings
Per day
12 months
Standard sample
3–5 working days
Typical retrieval
£0
Cost to access
Half-hourly meter data is electricity consumption recorded every 30 minutes — 48 readings per day, 17,520 readings per year. For a commercial solar quote, HH data is the difference between a generic forecast and a project-specific saving model accurate to ±5%.
What HH Data Shows
- Daily consumption profile: exactly when your business uses electricity and how much.
- Self-consumption ratio: the fraction of solar generation you would actually use vs export.
- Tariff exposure: if you're on a time-of-use tariff, HH shows your DUoS red/amber/green load distribution.
- Seasonality: how consumption varies through the year.
- Demand peaks: when (if ever) you hit triad-style demand peaks.
- Holidays and shutdowns: exactly how consumption drops during operational gaps.
Why HH Data Matters for Solar Sizing
Without HH data, solar quotes use generic assumptions — typically 60–70% self-consumption ratio and average grid pricing. With HH data, the installer models your actual hour-by-hour pattern, which:
- Sizes the system to your real load (oversized = wasted export at low rates; undersized = leaves savings on the table).
- Calculates your true savings by matching solar generation hours to your actual consumption hours.
- Tests battery storage payback against your real load pattern.
- Identifies time-of-use tariff savings opportunities.
- Gives an accurate (not generic) payback figure.
How to Access Your HH Data
- Check meter type: any commercial site over ~100kW peak demand has a HH meter installed by default. Smaller sites may have AMR (automated meter reading) or smart meters that record HH data.
- Request from supplier: ask your electricity supplier for "12 months of HH data" — most suppliers respond within 5 working days. Free of charge.
- Format: typically Excel (XLS) or CSV with columns for date, time, and kWh per half-hour interval.
- Alternative: third-party data services (Stark, Carbon Intelligence, Power-Logic) can pull HH data direct from your supplier with your authorisation.
Common Issues with HH Data
- Estimated readings: some suppliers fill HH gaps with estimates. A good analysis flags these.
- Multiple meters / sub-metering: sites with multiple supply points need each meter's HH data combined.
- Holiday spikes/gaps: if data covers an unusual operational period (e.g. COVID years), the installer may need to re-cut to a representative period.
- Tenant vs landlord supply: on tenanted buildings, the landlord supply and tenant supplies are separate — clarity needed.
What an Installer Does With Your HH Data
- Profile the load — daily, weekly, seasonal patterns.
- Generate a PVSyst-modelled solar generation forecast for your specific location.
- Match generation to consumption hour-by-hour for self-consumption ratio.
- Apply your specific tariff to calculate exact savings.
- Test multiple system sizes to identify the optimum.
- Test battery storage against the load pattern.
- Generate an accurate payback, IRR, and 25-year cashflow.
Frequently Asked Questions
What is half-hourly meter data?
Electricity consumption recorded every 30 minutes — 48 readings per day, 17,520 per year. Standard for UK commercial supplies above ~100kW peak demand.
How do I get my HH data?
Request from your electricity supplier — ask for '12 months of half-hourly data'. Most suppliers respond within 5 working days, free of charge. Typical format: Excel or CSV.
Why does half-hourly data matter for solar quotes?
HH data lets an installer model your actual hour-by-hour consumption against solar generation. This produces self-consumption ratios accurate to ±5% — vs generic assumptions that can be 15–25% off and skew payback calculations.
Do I need HH data to get a solar quote?
No, but quotes without HH data carry larger error bars on savings and payback. A good installer starts with HH data if available; if not, it uses sector-typical assumptions and flags the wider error range.
Can you help me get my HH data?
Yes — your installer can request it from your supplier on your behalf with your authorisation. Most suppliers process the request within 5 working days. Some customers prefer to request directly themselves; either route works.
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