Domestic Building Energy Ratings from a Social Perspective 2016

Introduction

The relationship between a household's socio-economic status and the energy efficiency of their dwelling is quite varied. Newer dwellings are being built to more rigorous standards to ensure that they are very energy efficient. The type of building has an important impact on the rating, with mid-floor apartments the most energy efficient and old detached houses the least energy efficient.

Geography is an indirect indicator of energy efficiency with counties and postal districts where a lot of new dwellings are being constructed having a higher proportion of energy-efficient dwellings. Occupants may live in a purchased dwelling for a long time, hence older persons are more likely to live in older less energy-efficient dwellings. However, there are many differences within and across socio-economic categories. Some of these differences are because the occupants cannot afford to upgrade the energy efficiency of their dwelling or to move to a more energy-efficient dwelling.

It is hoped that this report will be useful in identifying the characteristics of households that are the least energy efficient and where the occupants may not be able to afford to undertake the major energy refurbishment required to move towards a low-carbon economy.

Building Energy Rating

A Building Energy Rating (BER) is an indication of the energy performance of a dwelling (represented in units of kWh/m²/year). A BER is based on the characteristics of major components of the dwelling including wall, roof and floor dimensions; window and door sizes and orientations, as well as the construction type and insulation, ventilation and air tightness features; the system for heat supply (including renewable energy), distribution, and control; and the type of lighting.

Since 1st January 2009, a BER certificate and advisory report is compulsory for all homes being sold or offered for rent. A BER is required for new dwellings that apply for planning permission on or after 1st January 2007. A BER certificate is required to avail of the grants for energy-efficiency improvements to the home that are provided under the Better Energy Homes scheme.

The BER energy-rating scale is divided into categories from G (largest primary energy usage) to an A1 rating (lowest primary energy usage). The kilowatt-hour is the unit of energy used in Dwelling Energy Assessment Procedure. The BER is measured in kWh per square metre of floor area of the dwelling per year (kWh/m^₂/year). For the purposes of this report, the more detailed ratings have been combined into an A to G scale.

Table 4.1: Building Energy Rating Categories 

Census night

The Census of Population 2016 was taken on the night of Sunday, 24 April 2016, in accordance with the Statistics Act 1993 and the Statistics (Census of Population) Order 2015 (S.I. No. 445 of 2015).

Coverage of the Census

The Census figures relate to the de facto population i.e. the population recorded for each area represents the total of all persons present within its boundaries on Census night together with all persons who arrived in that area on the following morning not having been enumerated elsewhere.

Census 2016 questionnaire

A copy of the Census 2016 English household form can be downloaded at the following link: https://www.cso.ie/en/media/csoie/census/census2016/2016censusforms/65995_English_Household_2016_New_Version_Do_Not_Complete.pdf

Occupied private households

This report only includes private households where there was at least one person present on Census night. A private household comprises either one person living alone or a group of people (not necessarily related) living at the same address with common housekeeping arrangements - that is, sharing at least one meal a day or sharing a living room or sitting room.

Household reference person

The householder or any adult member of the household present on Census night could complete the form. The first person listed on the Census form was classified by the CSO as the household reference person. Other persons were defined in terms of their relationship to the first person e.g. husband or wife, son or daughter, etc.

Counties and Dublin postal districts

In Dublin, the four local authority areas are identified separately i.e. Dublin City and the three administrative counties of South Dublin, Fingal and Dún Laoghaire-Rathdown. Section 9 of the Local Government Reform Act 2014 provided for the amalgamation of the city and county councils in Limerick, Waterford, and North and South Tipperary County Councils. The Eircode was used to extract the Dublin postal district. Dublin postal districts are mostly located in Dublin City, but they can also be located in the other Dublin administrative counties.

Age group of reference person

This was created using the age of the reference person on Census night.

Sex of reference person

This was completed by the household.

Tenure status

Household tenure was derived based on whether the household owned or rented their accommodation.

Health of reference person

This was completed by the household.

Principal economic status of reference person

This was coded by Census staff.

Socio-economic group of reference person

This was coded by Census staff.

Household composition

The determination of household composition is based on responses to the question on the Census form dealing with relationships within the household.

Mobility difficulty of reference person

This was defined as persons who indicated that they had a long-lasting condition or difficulty which was defined as lasting for six months or more or regularly re-occurring.

Nationality of reference person

This was completed by the household.

Ethnicity of reference person

This was completed by the household.

Matching with Census of Population 2016

The Census of Population frame consisted of all occupied private dwellings. The Domestic Building Energy Ratings frame consisted of all households that had a Building Energy Rating certificate, an Eircode, and the building was completed in 2016 or earlier. If the dwelling had more than one BER audit, then the latest BER audit was used.

The matching between the Census 2016 and BER files was done using the Eircode. There were 1,640,768 occupied private households in the Census and 560,475 BER dwellings were matched with these at household level. The matching rate varied from around 50% in Galway city, Dublin 10 and Dublin 17 to 18% in Galway county.