EPC ratings confusion

J41721

Hi all

I am viewing 2 houses, they are similar size, 2 storeys, 3 bedroom semi-detached.
Their EPC rating differs a lot but I can't figure out why, house 1 has thicker loft insulation but then it has higher primary energy use.
I wonder how they calculate this.

J

House 1 - rating E - 40, potential C-75

Feature	Description	Rating
Wall	Solid brick, as built, no insulation (assumed)	Very poor
Roof	Pitched, 250 mm loft insulation	Good
Window	Fully double glazed	Average
Main heating	Boiler and radiators, mains gas	Good
Main heating control	Programmer, room thermostat and TRVs	Good
Hot water	From main system	Average
Lighting	Low energy lighting in 55% of fixed outlets	Good
Floor	Suspended, no insulation (assumed)	N/A
Secondary heating	Room heaters, mains gas	N/A

The primary energy use for this property per year is 400 kilowatt hours per square metre (kWh/m2).

House 2 - rating D - 62, potential B-87

Feature	Description	Rating
Wall	Solid brick, as built, no insulation (assumed)	Very poor
Roof	Pitched, 75 mm loft insulation	Average
Window	Fully double glazed	Average
Main heating	Boiler and radiators, mains gas	Good
Main heating control	Programmer, room thermostat and TRVs	Good
Hot water	From main system	Good
Lighting	Low energy lighting in 60% of fixed outlets	Good
Floor	Suspended, no insulation (assumed)	N/A
Secondary heating	None	N/A

The primary energy use for this property per year is 248 kilowatt hours per square metre (kWh/m2).

canaldumidi

EPCs are notoriously unreliable. They depend on an assessor having done a brief superficial training session, mostly focussed on how to input figures into the computer that generates the report (as opposed to learning to be a surveyor....).

Many of the figures they input are 'assumed' (guessed).

Even those that are not 'assumed' are often wrong.

If you want a good idea of how the property is constructed, what energy efficient measures exist etc, have a survey done and speak to your surveyor.

FreeBear

canaldumidi said:

EPCs are notoriously unreliable. They depend on an assessor having done a brief superficial training session, mostly focussed on how to input figures into the computer that generates the report (as opposed to learning to be a surveyor....).

Many of the figures they input are 'assumed' (guessed).

Even those that are not 'assumed' are often wrong.

If you want a good idea of how the property is constructed, what energy efficient measures exist etc, have a survey done and speak to your surveyor.

There is a detached house not far from me. The EPC (now expired) had the property described as being timber framed. It is in fact, solid brick like all the other houses near by.

If you want a better indicator of energy usage, ask the vendor how much gas/electricity they use, and what sort of temperature the keep the place heated to. Hard data will always trump a wet finger in the air & guesswork using "averages".

paddytt

Unless the EPC’s were done by the same person, I doubt the energy usage estimations are comparable.  

MaryNB

I used to live in a flat ground floor flat rated E. Flat above us was rated C. The only differences were we had energy efficiency bulbs, flat above didn't. We got marked down for no roof insulation, flat above didn't because there was another flat above it.

Load of nonsense. 

ProDave

I would not consider a house now worse than EPC C.

If you buy anything worse, you are gambling that someone is going to give you a grant to update it WHEN it needs updating.

I still maintain a house with a poor EPC should be worth less to reflect the work needed to bring it up to a decent standard.

I don't know why the EPC does not just quote the actual energy usage as measured by your gas bill?

RS2OOO

ProDaveProDave said:

I don't know why the EPC does not just quote the actual energy usage as measured by your gas bill?

Even that won't work for everyone as there are people who use most of their gas for things other than heating the house.

EPC rating for my house is quite good considering the age of the house, but it doesn't seem to account for the fact most of the heat goes straight up the chimney and there's a constant cold draught at ankle level!

p00hsticks

ProDave said:

I don't know why the EPC does not just quote the actual energy usage as measured by your gas bill?

That wouldn't work though - an rich OAP who is home all day, likes to keep really warm and cooks proepr meals in a gas oven would have much higher usage than someone frugal who is out at work all day and lives off microwave ready meals, even if their homes were absolutely identical.