To complete a DEC, energy data is required for a 12-month period. Typically this is gas and electricity, but could include LPG, oil or wood pellets.
If there are any on-site renewables – e.g. a solar PV array, the amount of energy generated is also required.
All the energy data must be for the same period (i.e. start-date is aligned within 30 days).
For a renewal DEC, the start date for the new energy data must be the end date of the previous DEC.
For a new DEC, the data needs to be recent, to enable the DEC expiry date to be set as far into the future as possible i.e. 15 months after the end date of the energy data.
For electricity consumption it is generally sufficient to supply meter readings at the start and end of the required period. However, if the meter is changed during this period, then the end reading for the old meter and the start reading for the new meter are also required.
Many properties have Half-Hourly (HH) meters, if this data can be supplied in spreadsheet form it meets the requirements for a DEC.
Gas consumption is slightly trickier as most meters measure either cubic metres (M3) or Hundreds of Cubic Feet (HCF) and the calorific value is required (this fluctuates from month-to-month) to convert the volume measured to the required kWh. For this reason it is generally necessary to provide the monthly (or quarterly) gas bills – these generally show the energy usage (in kWh) as well as the meter readings.
Energy consumption for fuel delivered in batches (such as LPG, Oil or Wood pellets) is harder still, as some estimation of levels and interpolation is usually required to obtain the energy usage for the year.