Glazing type | U-value/ |
---|---|
Single-glazing | 4.8 |
Double-glazing (normal glass, air-filled) | 2.7 |
Double-glazing (hard coat low-e, emissivity = 0.15, air-filled) | 2.0 |
Double-glazing (hard coat low-e, emissivity = 0.2, argon-filled) | 2.0 |
Double-glazing (soft coat low-e, emissivity = 0.05, argon-filled) | 1.7 |
Triple glazing (soft coat low-e, emissivity = 0.05, argon-filled) | 1.3 |
Material | Density/ |
Thermal conductivity/ |
---|---|---|
Aluminium (window frames) | 2727 | 220 |
Steel wall ties | 7900 | 17 |
Reinforced concrete (2% steel) | 2400 | 2.5 |
Window glass | 2600 | 1.05 |
Brickwork (outer leaf) | 1700 | 0.77 |
Plaster (dense) | 1300 | 0.57 |
Lightweight aggregate concrete | 1400 | 0.57 |
Aerated concrete | 600 | 0.18 |
Aerated concrete (lower density) | 460 | 0.11 |
Timber (softwood) | 500 | 0.13 |
Insulation material | Thermal conductivity/ |
---|---|
Foamed glass | 0.045–0.055 |
Mineral or glass fibre wool, sheep's wool, cellulose or hemp fibre | 0.032–0.040 |
Expanded and extruded polystyrene foam | 0.030–0.040 |
Polyurethane foam | 0.025 |
Polyisocyanurate (PIR) foam | 0.023 |
Phenolic foam | 0.022 |
Layer | Resistance / |
---|---|
Inside surface (Rsi) | 0.13 |
Air gap | 0.18 |
Outside surface (Rso) | 0.04 |
Layer | Thickness |
Conductivity/ |
Resistance/ |
---|---|---|---|
Outside thermal resistance | 0.04 | ||
Brick | 115 mm | 0.77 | 0.115/0.77 = 0.15 |
Mineral wool | 115 mm | 0.035 | 0.115/0.035 = 3.29 |
Aerated concrete block | 115 mm | 0.11 | 0.115/0.11 = 1.05 |
Dense plaster | 13 mm | 0.57 | 0.013/0.57 = 0.02 |
Inside thermal resistance | 0.13 | ||
Total thermal resistance | 4.67 |
Element | Area / |
U-value / |
Contribution to heat loss coefficient |
---|---|---|---|
Floor | 48 | 0.25 | 48 × 0.25 = 12 |
Roof | 48 | 0.16 | 48 × 0.16 = 7.7 |
Walls | 80 | 0.35 | 80 × 0.35 = 28 |
Windows and doors | 20 | 2.00 | 20 × 2.00 = 40 |
Total | 87.7 |
South Western | London (Thames Valley) | Midlands | Northern Ireland | Borders | North-East Scotland | |
---|---|---|---|---|---|---|
January | 281 | 319 | 356 | 343 | 345 | 367 |
February | 257 | 282 | 314 | 305 | 304 | 327 |
March | 239 | 242 | 278 | 286 | 295 | 313 |
April | 193 | 180 | 220 | 227 | 248 | 255 |
May | 112 | 97 | 136 | 150 | 180 | 183 |
June | 58 | 44 | 72 | 85 | 106 | 110 |
July | 25 | 18 | 36 | 46 | 57 | 62 |
August | 23 | 19 | 37 | 53 | 55 | 66 |
September | 50 | 48 | 76 | 92 | 95 | 112 |
October | 111 | 120 | 167 | 174 | 171 | 200 |
November | 193 | 227 | 264 | 258 | 260 | 285 |
December | 252 | 293 | 334 | 323 | 327 | 358 |
Total | 1794 | 1889 | 2290 | 2342 | 2443 | 2638 |
Heating system | Seasonal average efficiency |
---|---|
Open coal fire | approx. 32% |
New coal boiler | approx. 70% |
Electric fire | 100% |
Older gas fire | approx. 50% |
Typical 1980s wall-hung gas boiler | approx. 65% |
Gas condensing boiler | >85% |
Higher heating value/ |
Lower heating value/ |
Ratio | |
---|---|---|---|
Natural gas | 53.1 | 47.8 | 1.11 |
Liquefied petroleum gas (LPG) | 49.2 | 46.0 | 1.07 |
Light heating oil | 45.3 | 42.6 | 1.06 |
Emissions CO2 / |
|
---|---|
Natural gas | 0.21 |
Liquefied petroleum gas (LPG) | 0.24 |
Heating oil (gas oil) | 0.30 |
House coal | 0.40 |
Electricity (2020 generation mix) | 0.18 |
Lamp type | Details |
---|---|
General lighting service (GLS) | The traditional incandescent light bulb |
Tungsten halogen | |
Fluorescent high-pressure mercury discharge lamp (MBF) | Bluish white light, often used for shop lighting |
Metal halide high-pressure mercury discharge lamp (MBIF) | Bluish white light, used for street lighting |
Compact fluorescent lamp (CFL) | Replacement for normal incandescent light bulbs |
Tri-phosphor tubular fluorescent | Standard type for office and shop lighting |
High-pressure sodium discharge lamp (SON) | Orange-white light, used for street lighting |
Low-pressure sodium discharge lamp (SOX) and higher-efficacy version (SOX-E) | Pure orange light, used for street lighting |
Light-emitting diode (LED) |
Task | Recommended illuminance /lux |
---|---|
Circulation areas (stairs, corridors) | 150 |
Classroom desk | 300 |
Office desk, laboratory bench | 500 |
Electronics assembly | 1000 |
Hospital operating theatre | 2000 |
SAP or EIR rating | Label band |
≥ 92 | A |
81 – 91 | B |
69 – 80 | C |
55 – 68 | D |
39 – 54 | E |
21 – 38 | F |
1 –20 | G |