PROPERTY ENERGY EFFICIENCY CERTIFICATE DETAILS
William Street, CAERNARFON, LL55 1ND
Introduction
Energy Performance Certificates (EPCs) are designed to tell you how efficient a building is and provides a rating between A (very efficient) and G which is inefficient. It helps to identify how costly it will be to light and heat a property and what the carbon dioxide emissions are likely to be.
An EPC needs to be provided as part of the process of selling or renting a house and should be availale as soon as the property is marketed. An EPC may only be produced by an approved domestic energy assessor and each certificate is valid for 10 years.
Additionally, an EPC will highlight potential efficiency improvements that could be made to the property, an estimated cost for implementation and the likely savings that can be made as a result. These costs and savings are for a typical household in that property and not specific to you or your family.
Certificates issued for William Street, LL55 1ND are shown below and the data are updated monthly for England and Wales and quarterly for properties in Scotland.
Data are provided by the Department for Levelling Up, Housing and Communities.
Energy Performance Certificates Generated for William Street, CAERNARFON, LL55 1ND
Period Covered:
2008 - 31 January 2025
Address
Inspection Date
Current
Potential
Property Type
Built Form
Constructed
Address
10 William Street
Date
17 May 2009
Current
Potential
46
48
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
17 May 2009
46
48
Total Floor Area
81 sq m
Current CO2 Emissions Level
5.8
Potential CO2 Emissions Level
5.7
CO2 per sq m per Year
71
Mains Gas Available
Yes
Habitable Rooms
4
Number of Extensions
1
Address
11 William Street
Date
17 Oct 2016
Current
Potential
61
83
Property Type
House
Built Form
End-Terrace
Constructed
1900-1929
Certificate History
17 Oct 2016
61
83
Total Floor Area
94 sq m
Current CO2 Emissions Level
4.8
Potential CO2 Emissions Level
2.1
CO2 per sq m per Year
51
Mains Gas Available
Yes
Habitable Rooms
4
Number of Extensions
1
Address
12 William Street
Date
23 Feb 2017
Current
Potential
62
89
Property Type
House
Built Form
Mid-Terrace
Constructed
before 1900
Certificate History
23 Feb 2017
62
89
Total Floor Area
65 sq m
Current CO2 Emissions Level
3.5
Potential CO2 Emissions Level
1.0
CO2 per sq m per Year
54
Mains Gas Available
Yes
Habitable Rooms
3
Number of Extensions
0
Address
14 William Street
Date
21 Feb 2017
Current
Potential
61
89
Property Type
House
Built Form
Mid-Terrace
Constructed
before 1900
Certificate History
21 Feb 2017
61
89
27 Mar 2014
62
87
Total Floor Area
74 sq m
Current CO2 Emissions Level
4.1
Potential CO2 Emissions Level
1.1
CO2 per sq m per Year
55
Mains Gas Available
Yes
Habitable Rooms
3
Number of Extensions
0
Address
15 William Street
Date
27 Jan 2015
Current
Potential
53
88
Property Type
House
Built Form
Mid-Terrace
Constructed
before 1900
Certificate History
27 Jan 2015
53
88
Total Floor Area
66 sq m
Current CO2 Emissions Level
4.7
Potential CO2 Emissions Level
1.1
CO2 per sq m per Year
72
Mains Gas Available
Yes
Habitable Rooms
3
Number of Extensions
1
Address
16 William Street
Date
23 Feb 2017
Current
Potential
62
90
Property Type
House
Built Form
Mid-Terrace
Constructed
before 1900
Certificate History
23 Feb 2017
62
90
8 Feb 2017
67
90
Total Floor Area
77 sq m
Current CO2 Emissions Level
4.1
Potential CO2 Emissions Level
1.0
CO2 per sq m per Year
54
Mains Gas Available
Yes
Habitable Rooms
4
Number of Extensions
0
Address
17 William Street
Date
7 Nov 2012
Current
Potential
62
88
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
7 Nov 2012
62
88
Total Floor Area
74 sq m
Current CO2 Emissions Level
3.3
Potential CO2 Emissions Level
0.9
CO2 per sq m per Year
45
Mains Gas Available
Yes
Habitable Rooms
3
Number of Extensions
2
Address
18 William Street
Date
23 Feb 2017
Current
Potential
38
89
Property Type
House
Built Form
End-Terrace
Constructed
before 1900
Certificate History
23 Feb 2017
38
89
Total Floor Area
86 sq m
Current CO2 Emissions Level
7.9
Potential CO2 Emissions Level
1.3
CO2 per sq m per Year
92
Mains Gas Available
Yes
Habitable Rooms
5
Number of Extensions
0
Address
19 William Street
Date
22 Feb 2017
Current
Potential
23
91
Property Type
House
Built Form
Mid-Terrace
Constructed
before 1900
Certificate History
22 Feb 2017
23
91
Total Floor Area
65 sq m
Current CO2 Emissions Level
6.3
Potential CO2 Emissions Level
0.7
CO2 per sq m per Year
97
Mains Gas Available
Yes
Habitable Rooms
3
Number of Extensions
0
Address
2 William Street
Date
24 Jan 2017
Current
Potential
49
81
Property Type
House
Built Form
End-Terrace
Constructed
1900-1929
Certificate History
24 Jan 2017
49
81
2 Jun 2014
46
84
Total Floor Area
61 sq m
Current CO2 Emissions Level
4.9
Potential CO2 Emissions Level
1.9
CO2 per sq m per Year
80
Mains Gas Available
Yes
Habitable Rooms
3
Number of Extensions
1
Address
20 William Street
Date
11 Aug 2016
Current
Potential
55
86
Property Type
House
Built Form
End-Terrace
Constructed
1900-1929
Certificate History
11 Aug 2016
55
86
Total Floor Area
72 sq m
Current CO2 Emissions Level
4.8
Potential CO2 Emissions Level
1.4
CO2 per sq m per Year
67
Mains Gas Available
Yes
Habitable Rooms
3
Number of Extensions
1
Address
21 William Street
Date
8 Dec 2014
Current
Potential
60
90
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
8 Dec 2014
60
90
24 Mar 2014
12
90
Total Floor Area
58 sq m
Current CO2 Emissions Level
3.5
Potential CO2 Emissions Level
0.8
CO2 per sq m per Year
61
Mains Gas Available
Yes
Habitable Rooms
3
Number of Extensions
1
Address
22 William Street
Date
6 Jun 2023
Current
Potential
73
89
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
6 Jun 2023
73
89
29 Jun 2011
57
69
Total Floor Area
62 sq m
Current CO2 Emissions Level
2.3
Potential CO2 Emissions Level
0.9
CO2 per sq m per Year
37
Mains Gas Available
Yes
Habitable Rooms
3
Number of Extensions
1
Address
25 William Street
Date
13 Jun 2024
Current
Potential
55
77
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
13 Jun 2024
55
77
25 Nov 2010
40
51
Total Floor Area
76 sq m
Current CO2 Emissions Level
5.1
Potential CO2 Emissions Level
2.8
CO2 per sq m per Year
67
Mains Gas Available
Yes
Habitable Rooms
4
Number of Extensions
2
Address
25 WILLIAM STREET, CAERNARFON
Date
12 Nov 2020
Current
Potential
48
78
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
12 Nov 2020
48
78
Total Floor Area
80 sq m
Current CO2 Emissions Level
6.2
Potential CO2 Emissions Level
2.7
CO2 per sq m per Year
78
Mains Gas Available
Yes
Habitable Rooms
4
Number of Extensions
2
Address
27 William Street
Date
5 Oct 2014
Current
Potential
63
91
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
5 Oct 2014
63
91
Total Floor Area
55 sq m
Current CO2 Emissions Level
2.4
Potential CO2 Emissions Level
0.3
CO2 per sq m per Year
45
Mains Gas Available
Yes
Habitable Rooms
3
Number of Extensions
1
Address
28 William Street
Date
25 Nov 2019
Current
Potential
63
86
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
25 Nov 2019
63
86
Total Floor Area
76 sq m
Current CO2 Emissions Level
4.0
Potential CO2 Emissions Level
1.6
CO2 per sq m per Year
52
Mains Gas Available
Yes
Habitable Rooms
4
Number of Extensions
1
Address
29 William Street
Date
28 Apr 2022
Current
Potential
76
91
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
28 Apr 2022
76
91
25 Apr 2019
72
90
Total Floor Area
58 sq m
Current CO2 Emissions Level
1.8
Potential CO2 Emissions Level
0.7
CO2 per sq m per Year
31
Mains Gas Available
Yes
Habitable Rooms
3
Number of Extensions
1
Address
30 William Street
Date
20 Aug 2023
Current
Potential
68
87
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
20 Aug 2023
68
87
8 Mar 2012
46
60
Total Floor Area
68 sq m
Current CO2 Emissions Level
2.9
Potential CO2 Emissions Level
1.1
CO2 per sq m per Year
42
Mains Gas Available
Yes
Habitable Rooms
4
Number of Extensions
1
Address
32 William Street
Date
1 Feb 2016
Current
Potential
61
86
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
1 Feb 2016
61
86
6 Dec 2011
66
68
Total Floor Area
64 sq m
Current CO2 Emissions Level
3.7
Potential CO2 Emissions Level
1.3
CO2 per sq m per Year
57
Mains Gas Available
Yes
Habitable Rooms
4
Number of Extensions
1
Address
33 William Street
Date
18 Jan 2017
Current
Potential
46
76
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
18 Jan 2017
46
76
Total Floor Area
71 sq m
Current CO2 Emissions Level
5.8
Potential CO2 Emissions Level
2.7
CO2 per sq m per Year
82
Mains Gas Available
Yes
Habitable Rooms
4
Number of Extensions
0
Address
34 William Street
Date
5 Aug 2024
Current
Potential
23
81
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
5 Aug 2024
23
81
Total Floor Area
67 sq m
Current CO2 Emissions Level
7.7
Potential CO2 Emissions Level
1.9
CO2 per sq m per Year
115
Mains Gas Available
Yes
Habitable Rooms
5
Number of Extensions
1
Address
35 William Street
Date
11 Oct 2018
Current
Potential
71
87
Property Type
House
Built Form
Mid-Terrace
Constructed
1930-1949
Certificate History
11 Oct 2018
71
87
Total Floor Area
55 sq m
Current CO2 Emissions Level
2.3
Potential CO2 Emissions Level
1.0
CO2 per sq m per Year
41
Mains Gas Available
Yes
Habitable Rooms
4
Number of Extensions
1
Address
36 William Street
Date
30 Jul 2020
Current
Potential
75
89
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
30 Jul 2020
75
89
Total Floor Area
62 sq m
Current CO2 Emissions Level
2.0
Potential CO2 Emissions Level
0.9
CO2 per sq m per Year
32
Mains Gas Available
Yes
Habitable Rooms
4
Number of Extensions
1
Address
37 William Street
Date
4 Apr 2017
Current
Potential
40
89
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
4 Apr 2017
40
89
9 Jun 2010
27
37
Total Floor Area
70 sq m
Current CO2 Emissions Level
6.8
Potential CO2 Emissions Level
1.0
CO2 per sq m per Year
96
Mains Gas Available
Yes
Habitable Rooms
4
Number of Extensions
1
Address
38 William Street
Date
25 Mar 2012
Current
Potential
60
68
Property Type
House
Built Form
Mid-Terrace
Constructed
before 1900
Certificate History
25 Mar 2012
60
68
Total Floor Area
63 sq m
Current CO2 Emissions Level
3.4
Potential CO2 Emissions Level
2.6
CO2 per sq m per Year
54
Mains Gas Available
Yes
Habitable Rooms
3
Number of Extensions
1
Address
39 William Street
Date
19 Jul 2018
Current
Potential
68
82
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
19 Jul 2018
68
82
Total Floor Area
69 sq m
Current CO2 Emissions Level
3.2
Potential CO2 Emissions Level
2.0
CO2 per sq m per Year
45
Mains Gas Available
Yes
Habitable Rooms
3
Number of Extensions
2
Address
4 William Street
Date
17 Mar 2020
Current
Potential
63
78
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
17 Mar 2020
63
78
21 Jan 2009
63
69
Total Floor Area
58 sq m
Current CO2 Emissions Level
3.0
Potential CO2 Emissions Level
1.8
CO2 per sq m per Year
52
Mains Gas Available
Yes
Habitable Rooms
3
Number of Extensions
1
Address
40 William Street
Date
26 Jan 2023
Current
Potential
70
89
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
26 Jan 2023
70
89
20 Mar 2012
67
69
Total Floor Area
61 sq m
Current CO2 Emissions Level
2.6
Potential CO2 Emissions Level
0.8
CO2 per sq m per Year
42
Mains Gas Available
Yes
Habitable Rooms
4
Number of Extensions
1
Address
42 William Street
Date
7 May 2018
Current
Potential
58
83
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
7 May 2018
58
83
Total Floor Area
70 sq m
Current CO2 Emissions Level
4.3
Potential CO2 Emissions Level
1.8
CO2 per sq m per Year
61
Mains Gas Available
Yes
Habitable Rooms
3
Number of Extensions
1
Address
43 William Street
Date
20 Mar 2017
Current
Potential
54
79
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
20 Mar 2017
54
79
Total Floor Area
82 sq m
Current CO2 Emissions Level
5.0
Potential CO2 Emissions Level
2.1
CO2 per sq m per Year
61
Mains Gas Available
Yes
Habitable Rooms
4
Number of Extensions
1
Address
45 William Street
Date
26 Mar 2017
Current
Potential
7
81
Property Type
House
Built Form
End-Terrace
Constructed
1900-1929
Certificate History
26 Mar 2017
7
81
Total Floor Area
95 sq m
Current CO2 Emissions Level
11.0
Potential CO2 Emissions Level
2.5
CO2 per sq m per Year
116
Mains Gas Available
Yes
Habitable Rooms
6
Number of Extensions
1
Address
6 William Street
Date
14 Mar 2017
Current
Potential
63
90
Property Type
House
Built Form
Mid-Terrace
Constructed
1900-1929
Certificate History
14 Mar 2017
63
90
Total Floor Area
57 sq m
Current CO2 Emissions Level
3.1
Potential CO2 Emissions Level
0.8
CO2 per sq m per Year
55
Mains Gas Available
Yes
Habitable Rooms
4
Number of Extensions
0
Bands
Energy Performance Certificate Notes
There are a number of reasons that certificates are excluded from the dataset;
- The holder of the energy certificate has 'opted-out' of disclosure
- The certificate is excluded on the grounds of national security
- Certificates that are marked as 'cancelled' or 'not for issue'
Certificates are grouped together by the property reference identifier rather than the postal address with a view to showing the history of changes made to properties over time. Sometimes, one property may exist as multiple entries in the table instead and this is as a result of inconsistent building references being used on each prepared certificate.
Contains public sector information licensed under the Open Government Licence v3.0.
Contains Royal Mail data © Royal Mail copyright and Database right 2025.