Bog Roll ::

It's Not Magic, It's Work!

26 Feb 2013

Energy Performance Certificate

Last week someone in the village was asking about installing PV panels on their south facing roof. From 01 April 2013 the government will only allow the full feed in tariff if you have already fully insulated your house - it is obviously pointless generating electricity if your house leaks heat like a sieve.

I checked the EPC chart for our house that came with the HIP when we bought the house. It's quite pathetic, it reports loft insulation of 250 mm when in fact there was only 100 mm when we moved in. It does however note the old boiler with primitive controller and lack of efficient light bulbs. It then gives some bland advice and ranks the house at grade "E" with a SAP score of 48. The best the house could be is apparently grade "D" with a SAP score of 55. That corresponds to an annual energy use of 314 kWh·m-2 falling to a minimum possible of 275 kWh·m-2. Annoyingly there is no explanation of how a SAP rating relates to a energy use per unit area.

This is all utter rubbish! We changed all the old bulbs to mostly CFL, plus some LED and some halogen the day we moved in. Last autumn we put in a modern boiler and controller and started to insulated under the floors. We added 200 mm of loft insulation taking it up to a minimum of 300 mm over the whole loft with the spare in the centre to >400 mm. We have yet to replace the windows and doors (A rated) and complete the under-floor insulation.

For the first full year we were in the house we used 137 kWh·m-2 (a cold year too and with the old central heating boiler & controller), which is better than half the potential minimum energy use and last year we used only 104 kWh·m-2 (mild year plus new boiler for the last 2 cold months).

I am in favour of improving things, but if the official schemes and assessments are so rubbish how are people who don't know ever going to figure out what to do...