House-age estimator · PVGIS 5.3 · ONS
Your roof, your house's age
A year from the roof
3,269 kWh
3.5 kW facing south at 35° in the city centre, with the hills' horizon (PVGIS 5.3, our arithmetic).
Homes like this
9.3%
of Bradford homes built before 1930 reach EPC band C or above; for terraced homes of any age the figure is 21.2% (ONS).
The city centre has a conservation area of that name, one of 60 in the district: check whether your street is inside it (Bradford Council).
Thirteen places, with and without the hills
PVGIS, the European Commission's solar model, can include the horizon of the surrounding land, which matters in a district of valleys and moor edges. We ran a south roof at 35° for thirteen places both ways (PVGIS 5.3). The table runs from the lowest to the highest with the hills included.
| Place | Height (m) | With the hills | Open site | Hills take |
|---|---|---|---|---|
| Haworth | 240 | 906 | 913 | 0.8% |
| Keighley | 116 | 917 | 919 | 0.2% |
| Ilkley | 103 | 922 | 933 | 1.2% |
| Shipley | 77 | 929 | 934 | 0.5% |
| Thornton | 221 | 929 | 932 | 0.3% |
| Manningham | 126 | 933 | 933 | 0.0% |
| Saltaire | 88 | 933 | 934 | 0.1% |
| Bingley | 92 | 933 | 935 | 0.2% |
| City centre | 113 | 934 | 935 | 0.1% |
| Wibsey | 253 | 934 | 934 | 0.0% |
| Queensbury | 339 | 934 | 935 | 0.1% |
| Bradford Moor | 175 | 941 | 941 | 0.0% |
| Idle | 186 | 941 | 941 | 0.0% |
Most places lose next to nothing. The valley towns of the west and north lose a little more: Haworth, in the Worth valley, about 0.8%, and Ilkley, under its moor, about 1.2%. Height alone does not help or hurt: Queensbury, at 339 m the highest place we ran, sits level with the city centre.
Every direction
The way a roof faces matters far more than where it is. For the city centre at 35°, with the hills:
- South 934, south-east 882, south-west 875 kWh per kW a year.
- East 742 and west 735: close to four-fifths of south.
- North-east 580, north-west 577, north 505.
- Panels laid flat: 774.
In the city centre an east roof edges a west one, by 7 kWh per kW; the difference is small enough that the slope with fewer chimneys and less shade is usually the better choice.
Through the year
At the best angle in the city centre each kW makes about 35 kWh in January, 109 in June and 31 in December, and about 68% of the year's total arrives between April and September (our arithmetic from PVGIS). The estimator's small bars show the same shape for whichever place you pick. That summer weighting is why a battery helps most from spring to autumn: see batteries.
Age and type
The estimator's second panel draws on the ONS analysis of energy certificates for Bradford (ONS). The share of homes at band C or above is 9.3% for homes built before 1930, 34.7% for 1930 to 1982, 72.5% for 1983 to 2011 and 91.3% from 2012. By type it is 21.2% for terraced homes, 36.1% for semis, 46.8% for detached houses and 67.1% for flats.
Those figures matter in two ways. Homes below band C are the ones the Warm Homes: Local Grant can help, where the household also qualifies (help with the cost). And in an older stone house the order of work counts: panels lift the rating, but a survey may find insulation does more for comfort first (older homes and the EPC). The estimator also flags Saltaire, where every home in the Article 4 area is listed, and the places that share a name with one of the council's conservation areas (Bradford Council).
Reading an installer's estimate
Multiply the system size by the figure for your direction and place and you have a yardstick. RECC says its members follow strict rules for calculating performance estimates (RECC), and those rules can include shading that PVGIS does not see, so an estimate somewhat below the estimator is normal. One well above it deserves a question. For the price side, see what solar costs in Bradford, and for the checks on the firm, choosing an installer.
With a quote in hand, the quickest use of the estimator is this: pick the place nearest your house, set the direction of the slope the panels will go on, and move the size to the quote's kW. Note the yearly figure and set it beside the installer's. If the panels are split across two slopes, run each slope on its own and add the two results. Then set the era and the type to your house: if the share of similar homes at band C is low, it is worth reading older homes and the EPC before deciding what to do first, and help with the cost if the household might qualify for the council's grant route. Remember that the figures are long-term averages: one dull year can fall short of them, so judge a system over several years rather than a single summer.