Handley Park in Sixpenny Handley, near Salisbury, has the lowest energy efficiency of any street in England and Wales, reveals analysis of 23 million EPC certificates by the comparison service, Uswitch.com.

The cul-de-sac of 32 park homes has a median energy efficiency of just five – compared to a nationwide average of 67. This is due in part to a lack of insulation, and heating that is fuelled by bottled liquified petroleum gas (LPG).

Installing eight energy savings measures including wall and floor insulation, replacing boilers and adding high-performance external doors would increase the homes’ rating to 31. This would reduce households’ energy bills by almost half, but the measures would cost each resident between £9,535 and £21,675.

The ten streets with the lowest median EPC ratings include park homes, flats above high street shops, and detached mansions that cost more than £650,000^[3] but have uninsulated walls. All of the properties have the potential to dramatically improve their energy efficiency with insulation and other measures.

Table: Ten hardest streets to heat

Rank	Street	Reason for low rating	Median energy efficiency	Potential energy efficiency
1	Handley Park, Sixpenny Handley, Salisbury	Park homes, some heated with bottled LPG, some with no roof insulation	5	31
2	Falmouth Road, Redruth	Leaky walls, single-glazed windows, electric room heaters	6	53
3	High Street, Shrewsbury	Top-floor flats with single-glazed windows, no insulation and no low-energy lighting	6	33
4	Station Road, Port Talbot	Top-floor flats with uninsulated granite walls, single-glazed windows, and electric heaters	6	65
5	Foord Road, Folkestone	Top-floor flats with uninsulated cavity walls. Electric heaters and immersion heaters	7	69
6	The Street, Musbury, Axminster	Uninsulated granite walls, uninsulated pitched roof, no thermostat control in rooms	7	63
7	Ascot Road, Maidenhead	Detached houses with uninsulated walls and electric ceiling heating	8	60
8	Brynsiencyn, Llanfairpwllgwyngyll	Detached bungalows with underfloor heating from bottled LPG and uninsulated roof	8	76
9	Trawsfynydd, Blaenau Ffestiniog	Uninsulated granite walls and uninsulated pitched roof, electric room heaters and electric immersion heaters	10	95
10	Mount Pleasant, Staithes, Saltburn-By-The-Sea	Uninsulated walls and roof, electric room heaters and single-glazed windows	11	83

Source: Uswitch.com

Low energy efficiency is not due to one single cause, and among the 100 leakiest postcodes in the country are caravan parks, holiday homes, old rural properties and ten mansions.

Flats and maisonettes are the most energy-efficient homes in general, with park homes and bungalows commonly seeing greater heat loss. New-build homes are much more likely to have a higher EPC rating due to good insulation, and some even have solar panels and heat pumps pre-installed.

The most energy efficient street in England and Wales is Howgate Close, Eakring in Nottinghamshire, which is a row of one and two-bedroomed eco homes with triple-glazed windows and solar panels. Its median energy efficiency of 143 means it generates more electricity than it uses.

Nine of the ten roads in the best streets to heat have solar panels on their roof, half have heat pumps, and all of them have high-performance glazing like triple glazed windows.

Table: Ten best streets to heat

Rank	Road name	Reasons	Median Energy Efficiency
1	Howgate Close, Eakring, Newark	Air source heat pump, solar panels, high performance glazing	143
2	Glebe Close, Stoney Stanton, Leicester	Air source heat pump, solar panels, high performance glazing, underfloor heating	121
3	Muskett Way, Aylsham, Norwich	Solar panels, high performance glazing	121
4	Grover Gardens, Romford	High performance glazing, exhaust source heat pump	117
5	Cleeveton Row, Blakes Hill, North Littleton, Evesham	Solar panels, high performance glazing	114
6	The Waterside, Middleton St. George, Darlington	Biomass main heating, solar water heating, solar panels and high performance glazing	112
7	Rhiw Cefn Gwlad, Brackla, Bridgend	Air source heat pump, solar panels, high performance glazing	111
8	The Green, Goldenbank, Falmouth	Air source heat pump, solar panels, high performance glazing	111
9	King Georges Square, Middlesbrough	Solar panels, high performance glazing	110
10	Clos Yr Haul, Ammanford	Solar panels, high performance glazing	109

Source: Uswitch.com

Some 114 locations across England and Wales have an average energy efficiency of above 100, meaning they generate more power than they use.

Uswitch.com encourages households to check their home’s EPC certificate online, and see what improvements they could make to save money and energy.

Natalie Mathie, energy expert at Uswitch.com, comments: “Heating our homes is costing more than ever, so it’s shocking to realise just how much energy is leaking out through uninsulated walls and roofs.

“Every bit of heat that escapes your home will cost you money, so it’s worth knowing how efficient your home is.

“Take a moment to look up your home’s EPC certificate online and see where your property could be improved – the reports are incredibly detailed and will give you estimated costs for all the energy-saving measures.

“You can’t always tell if these changes are making a difference until you see your bill – unless you track your usage. People using the Utrack app can see the impact on their bills with hourly graphs, comparing gas and electricity use by day, week, month and year.”

Table: Costs of household energy savings measures

Energy saving measure	Installation cost	Annual saving	Years to pay for itself
DIY hot water tank insulation and primary pipe insulation	£31	£315	0.1
Hot water cylinder jacket	£21	£70	0.3
Chimney draught excluder	£18.50	£22	0.8
Radiator Reflectors	£14.08	£16	0.9
Draught proofing	£225	£125	1.8
Loft insulation (adding 270mm of insulation to uninsulated loft)	£640	£355	1.8
Cavity wall insulation	£1,000	£395	2.5
Loft insulation (upgrading from 110mm to 270mm)	£440	£35	12.6
Internal solid wall insulation	£8,500	£540	15.7
Floor insulation	£2,250	£110	20.5
External solid wall insulation	£12,000	£540	22.2
Installing A-rated windows	£7,500	£195	38.5