Portsmouth is the most densely populated city in the UK outside London — around 208,100 people on 40 square kilometres, in the council's own figures. Dense Victorian terraces, 25 conservation areas, and a city where a significant proportion of land sits in Environment Agency flood zones 2 or 3. All of that changes how a solar or heat pump installation gets designed.
A south-facing Portsmouth roof at around 35° generates roughly 1,124 kWh per year for every kWp installed — about 4,495 kWh from a 4 kWp array. Only Chichester does better across our whole patch, and Portsmouth beats inland Guildford by almost 10%.
Being on an island helps: low-lying, open to the south, and with far less of the tree shading that costs the inland suburbs their afternoons.
Portsmouth's terraces are narrow and the rear slopes are small. A good yield figure on a 12 m² roof still only supports a modest array, which is why we quote in kilowatt-hours the property will actually produce rather than in headline percentages.
| Town | kWh per kWp / year |
|---|---|
| Chichester | 1,175 |
| Portsmouth | 1,124 |
| Fareham | 1,117 |
| Bournemouth | 1,100 |
| Poole | 1,097 |
| Southampton | 1,080 |
| Salisbury | 1,046 |
| Winchester | 1,038 |
| Andover | 1,037 |
| Basingstoke | 1,031 |
| Guildford | 1,023 |
Source: European Commission PVGIS (v5.2), south-facing, 35° pitch, 14% system losses. Your own figure will differ with shading, pitch, orientation and roof area — the survey gives you a property-specific number, not this one.
Portsmouth City Council is blunt about it in its local plan: the city "is extremely flat, low lying and is located next to the sea. It is therefore one of the UK's cities most vulnerable to flooding", and "a significant proportion of the city falls within the Environment Agency flood zones 2 or 3".
For rooftop solar this changes little. For a heat pump it changes the design: the outdoor unit, its condensate run and the electrical isolation all sit outside at low level, and in a flood-zone property they want mounting with that in mind rather than dropped on a standard ground plinth because that's what the bracket kit came with.
Portsmouth City Council is the planning authority for the whole city. There's no National Park here — but there are 25 named conservation areas, and they cover a great deal of the most desirable housing.
Portsmouth sits in SSEN's SEPD area, the same distribution network operator as the rest of Hampshire.
Southsea, Old Portsmouth, Portsea, Milton, Copnor, North End, Fratton, Hilsea, Cosham and Drayton. Every installation is MCS accredited.
Aiko ABC panels, designed for narrow terraced roofs where every square metre counts. Portsmouth's yield is among the best we see, so a well-designed small array here performs better than a larger one inland — the trick is getting the most out of the area you actually have.
Solar panels →Grant, Midea and Daikin. In Portsmouth the siting question does most of the work: flood zone, boundary distances in tight terraced yards, and noise to a neighbour who may be three metres away. We survey all three before specifying a unit.
Heat pumps →Tesla Powerwall 3, Fox ESS and SigenEnergy, mounted high and dry. With a small roof and a good yield, storage is what turns a constrained array into a system that covers a meaningful share of your evening consumption.
Battery storage →About 1,124 kWh per year for every kWp installed, on a south-facing roof pitched at around 35 degrees, according to the European Commission's PVGIS dataset. That is roughly 4,495 kWh from a 4 kWp array, and it is the second-highest figure across the eleven towns we cover, behind only Chichester. Portsmouth benefits from an open southern aspect, a low latitude for the UK, and much less tree shading than the inland suburbs.
No, but it should change the design. The council states that a significant proportion of the city falls within Environment Agency flood zones 2 or 3, and that Portsmouth is one of the UK's cities most vulnerable to flooding. Rooftop solar is largely unaffected. An air source heat pump sits outside at low level, so in a flood-zone property we look at raising the unit on a plinth or wall-mounting it where the structure and the noise assessment allow, and we keep inverters and batteries well above any known water line.
Quite possibly. Portsmouth has 25 conservation areas and they cover a large share of the city's most sought-after housing, including Old Portsmouth, Portsea, East Southsea, Craneswater and Eastern Parade, The Seafront, Castle Road and Guildhall and Victoria Park. Inside a conservation area, panels on a wall or roof slope that forms the principal elevation and fronts a highway need planning permission from Portsmouth City Council. A rear slope not facing a highway is usually still permitted development.
Yes. The yield per panel here is among the best we see, so a small array performs better than the same array inland. The limit is square metres: a narrow rear slope might support six to eight panels. That is where high-efficiency modules and a battery matter, because storing what a modest array produces recovers much of what a bigger roof would have given you.
It changes who decides. Portsmouth has an unusually high proportion of tenanted property — the council recorded 5.1% of city dwellings as houses in multiple occupation against 2.5% nationally, and a city-wide Article 4 direction has applied to HMO conversions since November 2011. The installation is fixed to the building and the grid connection is registered against the property, so the owner has to agree. We quote landlords directly and can provide the EPC impact figures.
Portsmouth is in SSEN's SEPD area. Up to 3.68 kW per phase the G98 process applies, with no wait — we install and notify SSEN within 28 days of commissioning. Above that a G99 application must be approved first, with a network study and a connection quote. One rule matters more in Portsmouth than almost anywhere: SSEN requires prior approval where the same installer has connected generation at another property in the same postcode area within the previous 28 days, and in a city this dense a single postcode can cover dozens of homes.
Required to claim the BUS grant and to register for the Smart Export Guarantee. We are also RECC members.
Before specifying where a heat pump, inverter or battery goes — not after.
Family-run, with directly employed engineers. The people who survey your property are the people who install.
Survey to sign-off in one price, including scaffolding and the grid application. No hidden extras.
We will work out what your roof will actually generate, check your conservation area and flood zone position, and tell you where the equipment should go before you commit to anything.
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