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Energy Assessments Explained

Mon 10 February 2014

Energy assessments have been part of our lives since the autumn of 2007, and still after all these years, whilst many are aware of their existence, most people know absolutely nothing about them.


So let me explain: An Energy assessment provides the information to produce an EPC which is an asset rating that tells you how energy efficient a building is and its impact on the environment.

A is the best, coloured perfect “eco forest green”…. and G the worst (deep scarlet showing that your house lurks in the depths of inefficient squalor)… and is produced in a bar chart form very similar to the ratings given to new electrical appliances that you see whilst wandering the halls of Curry’s or John Lewis.

If you have a brand new home it’s likely to have a higher rating, reflecting the current building regulations requiring more and better insulation and more efficient heating systems, whist an older property, a lower rating.

The energy performance certificate also lists ways to improve the rating - such as installing double glazing or loft, floor or wall insulation. The theory being, the better the rating your property gets, the more attractive it should be to a buyer or tenant as it indicates lower energy bills.

But how is the rating calculated I hear you all asking… well firstly the assessment process makes one or two assumptions… well lots and lots of assumptions to be precise.

Firstly your pretty South Shropshire country cottage is assumed not to be in pretty South Shropshire, but in Derbyshire instead… now I’ve nothing against Derbyshire as such, but it’s not South Shropshire by any stretch of the imagination; However every single property that has an energy survey carried out, as far as the energy assessment is concerned, EVERY property is in exactly the same place in Derbyshire.

Furthermore every property is assumed to have the same occupancy levels, in this case a standard nuclear family of 2 adults and two and a half children. Based on this level of occupancy, it is further assumed that on average, this standard nuclear family is running approximately 7 baths a week to a standard depth and temperature, are standing under a shower for around 40 minutes a week.

During the colder months, every property is assumed to be heated Monday to Friday for 5 hours a day to 21c and for 9 hours a day at weekends. Now I don’t know about you, but that does seem a little excessive, whatever happened to putting on an extra jumper?

The energy assessor when visiting your home will them complete your assessment by recording what you possess in the way of heating:, boiler type and style and what fuel, temperature control and thermostats, insulation in the walls or internal or external, what is in the loft or roof space, whether any double glazing exists and what age it is, and where applicable energy saving and conservation measures such as PV or solar panels, windmills and the like. And finally make a calculation as to the volume of the property (length breadth and height).

With all that information the system then calculates what it reckons it will cost to heat and power your home for a period of 3 years, and issue a rating accordingly.

Simple really, however I have to impress upon you that the assessment carried out by your friendly energy assessor is non invasive. That is to say, carpet and floorboards wont be lifted, and holes not drilled into walls or ceilings; the assessor will only record what he can see or has access to written evidence or photographs, such as a guarantee or receipted invoice for works carried out. So for example if you having an energy assessment done and your property benefits from a converted loft done some time ago by a previous owner, then unless there is written evidence of insulation present in the eaves, for example, and the date on conversion is unknown, then the assessor has to assume the worst case scenario, ie that there is nothing there.. Likewise if you know that a previous owner has had the floor retro fitted with insulation - unless you have something to prove it, the assessor has to assume that its not there.

You may think that is wrong, but us Assessors are regularly audited on our energy reports and unless the auditors can reproduce the same results based on the evidence we have to upload to the Mother Assessor’s ship, ie by looking at the proof we provide, we fail the audit, fail more than one, and this seriously restricts the work the assessor can do in the future.

The system is not perfect, but what is there is what we have to work with, so please don’t blame your Assessor, he’s only doing his job.

Simon Smith - Bishops Castle (01588) 630070

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