Century-old homes more efficient than those built in the last decade, boiler study finds

Analysing Energy Performance Certificates, a USwitch boiler study has found century-old homes are more efficient than those built in the last decade.

Key points from study:

- Homes built post-2012 scored 5.39/10 on Uswitch’s heating and hot water efficiency index, only slightly higher than the national average of 5.00/10
- Homes built from 2003-2011 are the most boiler efficient, scoring 8.36/10
- Mid- and end-terrace houses draw with 5.00/10 for overall boiler efficiency
- Uswitch boilers expert, Ben Gallizzi, shares tips on how to improve your home’s boiler efficiency.

After a winter of record-high energy bills, many will be wondering how efficient their boilers are, and whether the type of home they have has an impact on this. The age of a property and whether it is detached, mid-terrace, or otherwise, can all have an impact on how hard a boiler needs to work, and ultimately how heat-efficient your household is.

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

Table 1: Boiler efficiency based on property age, ranked by final boiler score

Property age	Heating efficiency score (/10)	Hot water efficiency score (/10)	Boiler efficiency score (/10)
2003-2006	8.46	8.46	8.46
2007-2011	7.69	9.23	8.46
1996-2002	6.92	6.92	6.92
1900-1929	4.62	7.69	6.16
2012 onwards	9.23	1.54	5.39
1930-1949	3.85	5.38	4.62
1983-1990	5.38	2.31	3.85
Pre-1900	1.54	6.15	3.85
1950-1966	2.31	4.62	3.47
1991-1995	6.15	0.77	3.46
1976-1982	3.08	3.08	3.08
1967-1975	0.77	3.85	2.31

Source: Uswitch.com

Homes built from 2003-2006, and 2007-2011 are the most cost-effective to heat, according to Uswitch. Over half a million households benefit from the most efficient heating in the country, with properties built from 2003-2011 scoring 8.46/10. Homes built from 2003-2006 scored evenly for both heating and hot water efficiency, with 8.46/10. Whilst 2007-2011 homes are the most hot water efficient (9.23/10), but only the third most heat efficient (7.69/10).

Despite being the most modern homes analysed, properties built after 2012 are only the fifth most efficient based on a combined final boiler score of 5.39/10. Post-2012 properties account for the least EPCs, with just 93,918 properties. These modern homes are the most heating efficient, with a score of 9.23/10, however, 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 pre-1900, rank higher than properties built between 1950 and 1982, and 1991 and 1995.

Table 2: Boiler efficiency based on type of property, ranked by final boiler score

Property type	Heating efficiency score (/10)	Hot water efficiency score (/10)	Boiler efficiency score (/10)
Enclosed Mid-Terrace	8.57	8.57	8.57
Enclosed End-Terrace	7.14	7.14	7.14
End-Terrace	4.29	5.71	5.00
Mid-Terrace	5.71	4.29	5.00
Semi-Detached	2.86	2.86	2.86
Detached	1.43	1.43	1.43

Source: Uswitch.com

Boilers in detached properties have the lowest overall boiler score, scoring just 1.43/10 on average, based on 1.43 scores for heating and hot water efficiency. This is 7.14 points less than enclosed mid-terrace houses, which score highest (8.57/10).

Enclosed end-terrace and enclosed mid-terraced houses are the properties most conducive to boiler efficiency, scoring 7.14 and 8.57, respectively. These homes are also referred to as ‘back-to-back’ buildings, with two rows of terraces built together, meaning end-row properties only have two external walls, whilst mid-row properties have just one. As these homes have fewer external walls than other properties, the rate of heat loss is lower.

However, the number of enclosed terrace properties is dwindling, as their construction is prohibited and old properties are demolished or converted into museums. Both forms of enclosed terrace homes account for only 222,596 Energy Performance Certificates. Therefore, end-terrace and mid-terraced homes are the most energy efficient modern properties. With over six million properties, both age brackets have a final boiler efficiency score of 5.00.

Uswitch boilers expert, Ben Gallizzi, shares tips on how to improve boiler efficiency in your home:

“Certain property qualities can have an impact on your boiler’s efficiency, including factors such as age, type of property, and format of property.

“However, no matter your home’s age or format, there are steps you can take to maximise your boiler’s potential:

- - “Schedule a boiler check-up: Ensure that you regularly have your boiler checked over by an accredited engineer. An engineer will be able to check everything is running smoothly and address any worries you have around its efficiency.
  - “Bleed your radiators: To further improve the efficiency of your boiler, take the time to bleed your radiators. This eliminates any air pockets in the system, and reduces the pressure so you don’t have to turn the heating up as much.
  - “Invest in insulation: Having suitable insulation means a greater upfront cost but will likely save you money in the long run as the boiler has to operate for less time to achieve the same temperature.
  - “Choose the right boiler: Having a boiler that is compatible with the type of property you live in will also improve the overall heating efficiency of your home. To choose the right boiler, consider the size of your property, the number of residents, available fuel, and your existing system.”