Tariffs are easiest when you treat them as a data problem: what do you use, when do you use it, and what can you shift?
Night rate vs time-of-use (TOU): the simplest definitions
- Night rate: a cheaper unit price for electricity during an overnight window, with a higher price outside it.
- Time-of-use (TOU): multiple time blocks (often including peak/standard/off-peak), usually enabled by smart metering.
Exact windows and prices vary by supplier and can change — always check the supplier’s current terms and official sources.
How to compare tariffs without being misled
1) Start with your usage profile
If you have smart meter data, it’s often the best place to start. If not, you can still learn a lot from:
- Your bill history (overall consumption trends)
- High-load appliances (EV, heat pump, electric shower, cooking)
- A short monitoring period (see Home Energy Monitoring)
2) Identify “shiftable” loads
The most common shiftable loads are:
- EV charging (see Home EV Charger Installation in Ireland)
- Laundry/dishwasher cycles
- Some heat pump schedules (where appropriate)
If you can’t shift much, a complex TOU plan may not help.
3) Read the full pricing structure, not just the headline
Be careful with:
- Peak periods (if they exist)
- Standing charges and other fixed components
- Any conditions tied to smart meter availability
How solar and batteries interact with tariffs
- Solar reduces imported energy most when you use it during the day (see Solar Panels in Ireland).
- Batteries can shift energy into evening periods, and some setups can also charge from the grid (see Solar Batteries in Ireland).
Tariff choice is often easier after you understand your baseline demand.
Common questions
Do I need a smart meter for TOU?
Often, yes. Availability can depend on metering and supplier plans. See Smart Meters in Ireland.
Will a night rate always reduce my bill if I have an EV?
Not automatically. It depends on how much charging you do at home, whether you can consistently charge in the off-peak window, and what the day/peak prices look like.
Should I choose a tariff before installing solar or a battery?
You can, but it’s usually better to understand your demand profile first. Otherwise you risk optimising for the wrong pattern.
Related guides
- If you need the basics: Smart Meters in Ireland.
- If you want better data: Home Energy Monitoring.
- If you’re pairing with EV charging: EV Charging and Choosing an EV Charger.
- Browse all Guides.
Disclaimer: This guide is informational only. Tariff terms vary by supplier and can change. Always check official sources and current supplier documentation before making a decision.