What is interval meter data?

Interval meter data is your electricity consumption recorded at regular intervals — typically every 30 minutes (half-hourly data). Instead of just a monthly total, you get 48 readings per day showing exactly when and how much electricity your building used. This granularity reveals patterns that monthly bills can't show: baseload, peak demand, equipment schedules, and waste.

How do I access my business's interval meter data?

Contact your electricity supplier — they can provide your interval data in spreadsheet format. You can also access it through the ESB Networks customer portal if you have a smart meter. Some suppliers offer online portals where you can view and download your half-hourly data directly. There's no charge for accessing your own consumption data.

What is baseload and why does it matter?

Baseload is the minimum electricity your building draws at any time — typically visible as the flat consumption line at 3am on a Sunday. It represents equipment that's always on: refrigeration, servers, security systems, but also waste like heating running overnight, lights left on, and equipment on standby. For most offices, baseload should be 15–25% of peak-day consumption. If it's higher, there's waste.

Do all commercial premises have smart meters?

Ireland's national smart meter rollout covers both residential and commercial premises. Most commercial premises with higher consumption have had interval meters for some time. Smaller commercial premises are being upgraded as part of the national programme. Contact your supplier to confirm whether your premises has interval metering. Even older meters may have profile data available.

Can interval data tell me which equipment is using the most energy?

Interval data shows total consumption patterns, not individual equipment. However, experienced analysts can infer equipment usage from the data — heating shows as a step-change when the boiler fires, lighting shows as a consistent increase during operating hours, and equipment signatures are often identifiable. For equipment-level detail, sub-metering is needed alongside interval data.

Interval Meters, Half-Hourly Data, and What Your Energy Data Is Telling You

Your commercial premises almost certainly has a smart meter. That meter records your electricity consumption every 30 minutes, 24 hours a day, 365 days a year. The data it collects tells a detailed story about how your building uses energy.

But almost no one reads that story. The data sits on a server somewhere while you look at monthly bills that show nothing useful.

This guide explains what interval meter data is, how to get yours, and what it reveals about your building’s energy consumption. It’s the technical companion to our guide on energy monitoring.

The Quick Version

Smart meters record your consumption every 30 minutes (half-hourly data)
This data is available to you for free from your supplier or ESB Networks
It reveals: baseload (waste), peak demand, equipment schedules, and seasonal patterns
Baseload analysis alone typically identifies 5–15% savings opportunities
Manual analysis works for basics; automated platforms unlock deeper insights
Energy audits use interval data as a primary diagnostic tool

What Interval Meter Data Looks Like

Instead of a single number on a monthly bill (e.g., “3,450 kWh”), interval data gives you 48 readings per day — one for every 30-minute period.

A typical weekday profile for a small office might look like:

Time	Consumption (kWh)	What’s Happening
00:00–06:00	0.8–1.0 per half-hour	Baseload — servers, security, standby
06:30–07:00	1.5	Heating starts, lights come on
07:30–09:00	3.0–3.5	Staff arrive, equipment on, full heating
09:00–17:30	3.0–4.0	Normal working day
17:30–18:30	2.5	Staff leaving, some systems winding down
18:30–20:00	1.5	Cleaning, late workers
20:00–23:30	0.8–1.0	Back to baseload

The weekend profile should look different. If your Sunday profile looks like your Tuesday profile, something is running that shouldn’t be.

Five Things Interval Data Reveals

1. Your real baseload

Baseload is the minimum consumption your building draws at any point — visible in the data as the flat line during the quietest hours (typically 2am–5am on a Sunday or bank holiday).

What it should be: For a typical office, 15–25% of peak-day consumption. For retail, 10–20%. For hospitality, 25–35% (due to refrigeration and security).

What it often is: 40–60%. The excess is waste — heating running overnight, lights left on, equipment on standby, ventilation fans running at full speed into an empty building.

What to do: Calculate your baseload from the data. Multiply it by 8,760 hours per year. The result is your annual baseload consumption. Now ask: which of those kWh are necessary (servers, refrigeration, security) and which are waste?

2. When your heating starts and stops

Gas heating doesn’t show directly in electricity interval data (it’s on a separate meter), but the timing of electrical consumption changes reveals heating patterns:

A step-up in consumption at 6am on a Monday? That’s the boiler pump and controls starting.
Still elevated at 8pm? The heating is running too long.
Same profile on Saturday as Tuesday? Weekend heating is on.

For buildings with electric heating or heat pumps, the heating load is directly visible in the electrical profile.

3. Equipment that never switches off

Look at the overnight profile on a weekday vs a weekend. If they’re the same, everything that runs during the week is also running at weekends. Now ask: should it be?

Common overnight/weekend loads that shouldn’t be running:

Office equipment and monitors on standby (not truly “off”)
Vending machines and water coolers
HVAC systems on override
Lighting in areas with no occupancy
Extraction fans running continuously

4. Seasonal consumption shifts

Plotting monthly profiles over a year shows how your building responds to seasons:

Higher consumption in winter = heating-dominated (expected)
Higher consumption in summer = cooling-dominated (check sizing)
Flat profile regardless of season = consumption independent of weather (investigate)

A flat seasonal profile often means heating and cooling are fighting each other, or that non-weather-dependent loads (lighting, equipment) dominate.

5. The impact of changes

Before and after any energy improvement, interval data shows the actual impact:

LED lighting installed? The daytime profile should drop by the lighting load
Heating controls optimised? The start-up should align with occupancy and the weekend profile should flatten
Equipment standby reduction? The overnight profile should drop

This verification is crucial for maintaining savings and proving return on investment.

How to Access Your Data

From your electricity supplier

Contact your supplier’s business customer service and request your interval data (half-hourly data) for the past 12 months. Most suppliers provide this as a CSV or Excel file. Some have online portals where you can view and download data directly.

From ESB Networks

If your premises has a smart meter registered with ESB Networks, you may be able to access data through their customer portal. The data is the same — your supplier and ESB Networks both have access to your meter readings.

What format to expect

You’ll typically receive a spreadsheet with columns for:

Date and time (each half-hour)
Consumption (kWh) for that period
Sometimes separated into import and export (if you have solar PV)

12 months of half-hourly data is approximately 17,500 rows — manageable in a spreadsheet for basic analysis.

Basic Analysis You Can Do Yourself

Baseload calculation

Filter for Sundays and bank holidays (or any day the building is completely unoccupied)
Look at the 02:00–05:00 period
Average those readings
Multiply by 2 (to get hourly kWh) × 8,760 (hours per year)
This is your annual baseload consumption

Example: Average 3am Sunday reading = 0.9 kWh per half-hour → 1.8 kWh/hour → 15,768 kWh/year. At 28c/kWh, that’s €4,415/year running through your meter every night and weekend.

Peak demand identification

Sort the data by consumption (highest first). Your peak demand periods reveal:

When your building draws most power
Whether peaks are regular (operational) or spikes (equipment issues)
Whether demand charges on your bill are driven by genuine need or avoidable peaks

Day type comparison

Average the profile for weekdays, Saturdays, and Sundays separately. Plot all three on the same chart. The differences (or lack thereof) immediately show:

Whether weekend consumption is appropriately lower
Whether Saturday and Sunday profiles differ (they should if heating/lighting is off)
What proportion of weekday consumption is genuine operational need vs waste

The Limits of Manual Analysis

Spreadsheet analysis of interval data works for the basics — baseload, peak demand, day-type comparison. But it has practical limits:

What manual analysis struggles with

Weather normalisation — separating consumption changes due to weather from changes due to waste
Automated alerting — you’d need to check the data daily to catch problems quickly
Equipment-level disaggregation — without sub-meters, separating heating from lighting from equipment requires pattern recognition that’s time-consuming manually
Long-term trend analysis — year-on-year comparisons with multiple variables
Benchmarking — comparing your building against similar buildings

When to move beyond manual analysis

If your energy spend is above €15,000/year, or if you’ve made significant energy investments that you need to protect, consider an automated energy management platform. These platforms:

Ingest your interval data automatically
Apply weather normalisation
Alert you to anomalies within 24 hours
Provide dashboards and reports
Benchmark against similar buildings
Cost €50–€200/month for SME-level platforms

The alternative is manual analysis monthly — better than nothing, but slower to catch problems.

Interval Data and Energy Audits

When we conduct a commercial energy audit, interval data analysis is one of the first things we do — often before the site visit. The data tells us:

Where to look during the site survey (high baseload? check what’s running overnight)
How the building compares to benchmarks (high consumption per m²? there’s waste)
Whether controls are working as intended (heating profile matches schedule? or not?)
What the realistic savings opportunities are

If you’re considering an energy audit, having your interval data available accelerates the process and improves the quality of recommendations.

Next Steps

Request your interval data from your electricity supplier — it’s free and usually available within a few days
Calculate your baseload using the method above — this single number often reveals thousands of euros in annual waste
Book a commercial energy audit — we’ll analyse your data professionally and identify specific savings
Read our monitoring guide to understand how ongoing monitoring protects your savings

Your smart meter is collecting valuable data about your building every 30 minutes. That data can tell you exactly where your energy goes and where you’re wasting money. The only question is whether anyone’s reading it.

Interval meter data is the most underused resource in Irish business energy management. It’s free, it’s available, and it reveals things that monthly bills never will. The businesses that use it consistently spend less on energy than those that don’t.