Challenging an EPC

debitcardmayhem

Here is an example of a similar property to mine , and to put this in perspective see my comments after it

 
Now 1621 for heating, hot water and lighting….  What about cooking, washing, showering etc?
11200+ kWh at what temperature is it heated to? My costs are 21000kWh health reasons admittedly
Save £266 by suggested steps inc PV, Solar water heating , floor insulation yeah at a cost of c 15000
2023 prices

Realistically I spent 9600 in 2023 on PV and battery savings c 1500 and using gas tracker saves c 15% on gas costs.
These EPCs are a much use as the OFGEM average consumption for high medium low, challenging them is a waste of your time as is the exercise of compiling them.

matt_drummer

Is it a big deal when choosing a home?

I suggest not.

The size of the home, the layout and where it is are the most important factors.

Ask the owners about their bills and how they live and make your own mind up.

The epc is meaningless.

Who really cares when looking to buy a new home?

It's obvious with careful viewing and the right questions how much it might cost to run. I don't think many people look at heating costs as the main priority when choosing a new home!

i doubt an epc that's a few points lower than you think it should be will make any appreciable difference to how much you can sell your home for.

Ildhund

debitcardmayhem said:

These EPCs are a much use as the OFGEM average consumption for high medium low, challenging them is a waste of your time as is the exercise of compiling them.

Where do you see Ofgem average consumption figures?

Perhaps you meant to refer to their Typical Domestic Consumption Values, which aren't averages at all. The three levels - low, medium and high - are simply those that 25%, 50% and 75% of households respectively used less than during the years of the survey*. They are useful for the purpose for which they were assessed. Many would say that an EPC may not be quite so useful. 
  

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*  

The established methodology derives the typical low, medium and high TDCVs for gas and electricity by calculating the lower quartile, median and upper quartile of household consumption for the two most recent years of available data, and then takes the average.

  
Decision on revised Typical Domestic Consumption Values for gas and electricity and Economy 7 consumption split

Bilivino

Nsar2 said:

Bilivino said:

2004? EPCs weren’t introduced until 2007. Also the fuel prices used in the methodology are fixed so there is no state of ‘flux’ in the ratings.

Sorry 2014.
That's my point about the EPC just done. The assessor and his training body Elmhurst have both said that the reason that the rating has fallen (even though the insulation and energy consumption of the property have been radically improved since 2014) is because fuel prices have risen.
They seem unable to answer basic questions and are now blaming it on new regs introduced in June which recognise the presence of batteries with PV. This is a partly true answer because prior to June the presence of PV was aknowledged (but not batteries) but they can't say what impact the PV has had on the ratings other than to say "it would have been worse". The fact that I'm a net exporter of electricity now and my oil consumption has fallen a lot because a lot of my water heating is by solar is simply disregarded.
They also didn't ask for my MCS certificate so their assessement of my PV array is based on percentage of the roof area which itself is rubbish because the panels are on an attached barn which does not form part of the main house whci is what they are rating. It's a mess.

Ok. With understanding EPCs, the detail is really important. To help you out, there are two sets of fuel costs used by the EPC methodology for existing dwellings. One set is fixed, and my understanding is that set has remained the same since approximately 2014 (iirc), and continues to do so even since 15th June 2025 when RDSAP 10 (which you refer to) was introduced.These values are used in the calculation of the headline EPC rating which is a cost-based metric. The fixed nature of these fuel costs contribute towards the long term stability of an EPC rating for a property over time. There is also a second set of fuel prices used, which are updated every 6 months, but which are only used in calculations for energy useage figures on the EPC and formulation of the Recommendations. I don't know exactly when that first set were last changed, relative to your earlier EPC so I can't comment on 'because fuel prices have risen'. However, there have been other changes in the methodology over those last 10 years which can affect ratings, depending on the property. With assessment of solar PV, documentation is vital to confirm the peak capacity of the installation, and more so in your case. The percentage of roof method only considers the roof of the property (main building plus any extensions), for a single dwelling, and will not include solar panels on any nearby barn etc if they are electrically connected to your property. This method also only uses a figure of 120Wp per m2 which is very low compared to modern solar panel capacities. Contact your energy assessor, provide a scan of the MCS certificate and ask for the EPC to be re-issued (they should have asked about documentation). If that doesn't happen, well for me life is too short, I would just find another assessor and provide the information up front. With your solar water heating, is that by 'Solar Thermal' panels, or is it via a PV Diverter? Under the latest methodology that's a really import question. Just as important is this very specific question which you will frown at: Is your electricity meter export capable? Just out of personal interest, how much did you pay for the EPC? Regarding home batteries, they can now be recorded under the new methodology, but they won't increase the EPC rating unfortunately, unless you don't have an export capable meter. Lastly, was your new EPC conducted under RDSAP 10 (ie since 15th June 2025)?

Bilivino

debitcardmayhem said:What about cooking, washing, showering etc?

Cooking is an 'unregulated' energy use, not subject to Part L of the building regs so not considered by EPCs. Showering is covered under hot water costs.

Nsar2

Thanks Bilivino, the assessor didn't ask for the MCS certificate and I have since sent it to him and await his reponse. The heating of the water during the summer months when the AGA is switched off is by immersion heater, not a seperate/dedicated system. The meter is export capable, it 's how we know that we are net exporters of electricity. We paid £120. The assessment was done in May