Kilowatt.ie runs a simulation of your electricity imports and exports for each half-hour time slot over the course of a full year.
Based on this, we can rank every kind of electricity tariff on cost.
General Assumptions
- For comparisons based on your kWh consumption or the “National Average” (4,200 kWh per annum), we assume the following split across times of the day (flat within each time band):
| Band | Hours | Units | Proportion | Average Power |
|---|---|---|---|---|
| Peak | 5pm – 7pm | 420 | 10% | 0.57534 kW |
| Night | 11pm – 8am | 2226 | 53% | 0.47306 kW |
| Day | All other times | 1554 | 37% | 0.46913 kW |
- VAT is included in all comparisons
- “Cashback”, “Welcome Bonuses”, and unit rate discounts are included in the calculations.
NB: It’s standard practice for electricity suppliers to jack up prices once your contract expires. To get a good value, you need to re-evaluate your options and most likely switch again as soon as your contract expires. Mark your calendar!
Smart Meter Data
Where the smart meter data you upload contains more than 12 months of records, we will trim this to the most recent 12 months for comparison purposes. This eliminates the risk of biasing your results with seasonality, and focuses the comparison on the data which is most up-to-date.
Where the smart meter data contains fewer than 12 months of records, we will use the entire dataset, and provide a warning that results may be less accurate.
Kilowatt.ie is designed to work only with HDF-format half-hourly smart meter data from ESB networks. Please avoid opening the dataset on your computer before uploading, as doing so can cause formatting changes which prevent the comparison from working correctly.
Dynamic Tariffs
Dynamic tariffs include “dynamic pricing component” which is tied to the half-hourly wholesale electricity price.
Kilowatt.ie compares dynamic tariffs with the use of real half-hourly electricity pricing data from the day-ahead wholesale electricity market. If you upload your smart meter data, we can match your usage on a half-hour by half-hour basis to the wholesale price at each moment in time. This allows us to run an accurate calculation of what your bills would have been if you were on a given dynamic tariff over the past 12 months.
You may adjust from there based on your expectations for how dynamic prices may evolve over the coming 12 months.
Battery Simulations
Batteries are assumed to be AC-coupled, and have a round-trip efficiency of 87%, unless otherwise specified. Capacity refers to the usable discharge amount on the AC side per cycle.
We assume max charge/discharge rates according to the following table, unless otherwise specified.
| Battery Capacity | Assumed Max Charge/Discharge Rate |
|---|---|
| 1 kWh | 1 kW |
| 2 kWh | 2 kW |
| 3 – 6 kWh | 3 kW |
| 7 – 10 kWh | 4 kW |
| 10-24 kWh | 6 kW* |
| >24 kWh | 11 kW** |
** Approx three-phase limit
EV Charging Simulations
EV charging is assumed to start at the following times, depending on the amount of charge to be supplied:
| Charge Amount | Start Time |
|---|---|
| ≤ 24.5 kWh | 02:00 |
| 24.5 kWh – 28 kWh | 01:30 |
| 28 kWh – 31.5 kWh | 01:00 |
| 31.5 kWh – 35 kWh | 00:30 |
| > 35 kWh | Midnight |
We assume that your charger runs at 7kW (AC), and continues until the specified number of (AC) kWh have been consumed.
For EV charging, all energy/power amounts refer to the consumption by the charger. This will be slightly higher than the energy delivered to the EV battery due to conversion losses inside the charger
Solar Panel Simulations
We simulate the performance of solar panels using Typical Meteorological Year data for the geographical centre of Ireland.
Inverter AC power is assumed to be limited to 5.5kW. Clipping is assumed above this amount.
Within each given half-hour time band, we assume that any simulated solar production can be used to offset imports.
Heat Pump Simulations
Heat pump simulations assume that no heating is required until the outside air temperature drops below 16°C, linearly increasing as the temperature decreases below that point.
We assume a Heat Loss Indicator of 2.0.
We source hourly temperature data (both for heat demand and air-source heat pump efficiency) from the typical meteorological year for the geographical centre of Ireland.
We assume a heat pump COP of 3.25 for an air temperature of 0°C, increasing by 0.0875 for each degree of temperature increase above 0°C and decreasing by the same amount for each degree of temperature below 0˚C.
We also assume an always-on approach to heating control for the heat pump.
Payment Methods
Where a supplier requires a certain payment method to be used for the first payment, but allows flexibility for subsequent payments, we still interpret this to mean that the mandated payment method is “required” for the tariff.