New vs old: which is more

After a winter of record high energy bills, consumers may be wondering how efficient their boilers are and what they can do to improve the overall efficiency of their home.

Many different factors affect how hard a boiler needs to work to heat hot water and warm a property to the right temperature, including the age of the property and whether it is detached, semi-detached or mid-terrace.

To discover which property type and age has the greatest impact on the boiler’s efficiency, a study by Uswitch analysed Energy Performance Certificates (EPCs) across Great Britain. Using the EPC ratings for the energy efficiency of the hot water system and the main heating system, all the properties studied were then given a final boiler efficiency score and compared, based on their age and property type.

Taking into account both hot water and heating efficiency, the study found that homes built between 2003 and 2006, and from 2007 to 2011, were the most efficient overall.

Homes built between 2003 and 2006 scored evenly for both heating and hot water efficiency, with a final score of 8.46/10.

Homes built between 2007 and 2011 are the most hot water efficient (9.23/10) but only the third most heat efficient (7.69/10).

Properties built after 2012 were found to be only the fifth most efficient despite being the most modern homes analysed, based on a combined final boiler score of 5.39/10. And although these modern homes are the most heating efficient, with a score of 9.23/10, they are the second least hot water efficient, scoring just 1.54/10.

Meanwhile, homes built a century earlier, between 1900 and 1929, have an overall boiler efficiency score of 6.16. In fact, the oldest homes analysed, those built before 1900, ranked higher than properties built between 1950 and 1982, and 1991 and 1995.

Property type

When comparing the efficiency scores by property type, detached properties had the lowest overall boiler score, scoring just 1.43/10 on average, with the same figures for heating and hot water efficiency. This is significantly less than enclosed mid-terrace houses, which scored the highest (8.57/10).

Enclosed end-terrace and enclosed mid-terraced houses are the properties most conducive to boiler efficiency,