Solar Panels on North-Facing Roofs

The Real Cost: North-Facing Solar Economics

The Real Cost: North-Facing Solar Economics

Most orientation guides stop at relative output percentages. That is not enough to make a £6,000–£8,000 decision. Below is the same 4kW system (around 10 panels) modelled across four orientations using current UK figures: a 29p/kWh import price, a 15p/kWh Smart Export Guarantee export rate (broadly the best fixed SEG rate available in 2026), an installed cost of roughly £1,400 per kWp, and 0% VAT (zero-rated until 31 March 2027). Self-consumption is the share of generation you use in the home rather than export.

Orientation	Annual output (kWh)	Self-consumed	Bill saving / yr	SEG export / yr	Total benefit / yr	Simple payback	Lifetime cost p/kWh*
South	3,800	37%	£408	£359	£767	~7–8 yrs	~7p
East–West split	3,150	45%	£411	£260	£671	~8–9 yrs	~8p
North-West	1,900	50%	£276	£143	£419	~13–14 yrs	~14p
North	950	52%	£143	£68	£211	~26+ yrs	~28p

*Lifetime cost per kWh = installed cost divided by ~25 years of generation, before degradation. The honest takeaway: a south or east–west system pays for itself comfortably inside the panels' warrantied life. A true north-facing 4kW array on its own does not — its lifetime cost per unit (~28p) is barely below what you pay the grid today, so the financial case is weak. A north-west roof is borderline rather than hopeless. Figures are indicative for a Midlands property; your survey numbers will differ.

Will It Pay Back? North-Facing Payback Periods

Will It Pay Back? North-Facing Payback Periods

Payback is where orientation really bites. A well-sited south-facing 4kW system in the Midlands typically returns its cost in around 7–8 years. A north-facing array of the same size generates so little that simple payback stretches past 25 years — beyond the point most people would consider a sensible standalone investment.

There is one important exception, and it changes the maths completely: adding panels to a north slope alongside an existing south or east–west array. When the inverter, scaffolding, electrical work and survey are already paid for, the marginal cost of a few extra north-facing panels is just the panels and rails. On that incremental basis the payback can fall to roughly 12–15 years rather than 25-plus, because you are only counting the cheap part of the bill against modest-but-real extra generation.

• North-facing as your only array: payback ~26+ years — we will usually advise against it.
• North-facing slope added to a larger system: marginal payback ~12–15 years — sometimes worth it for the extra self-used units.
• North-west slope, standalone: ~13–14 years — borderline, depends on your import price and how much you use during the day.

We would rather tell you the figures don't stack up than sell you panels that take a quarter of a century to break even. If your survey numbers are marginal, we will say so.

The Self-Consumption Advantage: Why North Isn't All Bad

The Self-Consumption Advantage: Why North Isn't All Bad

There is a genuine, often-overlooked point in favour of north and north-west roofs, and it is about timing, not quantity. South-facing panels peak hard around midday, when many households are out and electricity demand is low — so a large share of that generation gets exported at 15p rather than offsetting a 29p import. North and especially north-west panels generate a flatter curve that holds up later into the afternoon and early evening, closer to when families are actually home cooking, washing and charging devices.

The practical effect is a higher self-consumption rate: in our modelling a south array self-uses around 37% of its output, while a north-facing array self-uses closer to 52%. Because a self-used unit is worth 29p (avoided import) versus 15p exported, each north-facing kWh is worth slightly more per unit than a south-facing one.

Be clear about what this does and doesn't mean. It does not rescue the overall economics — a north roof still generates far fewer total units, so the annual benefit is much lower (see the cost table above). What it does mean is that the gap is narrower than the raw output percentage suggests, and that on a north-west roof, paired with a household that uses power in the afternoon and evening, solar can still be a reasonable proposition. A battery (Tesla Powerwall, GivEnergy or Fox ESS) pushes self-consumption higher still on any orientation, which is why we often pair storage with non-ideal roofs.

Real Install: A North-Facing System We Monitored

Real Install: A North-Facing System We Monitored

Percentages are easy to argue about, so here is a monitored, like-for-like comparison from our own work. On one semi-detached property near Lichfield the homeowner had panels on both the main south-west slope and a smaller north-east garage roof, with the same panel model and a single hybrid inverter logging each string separately. Over a full 12 months we read the generation off the inverter portal:

String	Spec	12-month generation	Per kWp
South-west slope	8 × 440W (3.52 kWp)	3,210 kWh	~912 kWh/kWp
North-east slope	4 × 440W (1.76 kWp)	880 kWh	~500 kWh/kWp

Per kWp, the north-east string produced roughly 55% of what the south-west string delivered — almost exactly what the orientation tables predict for a north-east aspect. The owner kept the north-east panels precisely because the marginal cost was low and the extra afternoon generation lifted their self-consumption. This is a single real property, not a laboratory test, and your roof's pitch, shading and inverter setup will move the numbers — but it is a useful sanity check on the percentages above. (Details anonymised at the customer's request.)

Does Location Matter? North Roofs in Scotland vs Southern England

Does Location Matter? North Roofs in Scotland vs Southern England

Yes — and it matters more for north-facing roofs than for any other orientation. A south-facing roof gets direct sun whatever the latitude. A north-facing roof relies far more on diffuse (cloud-scattered) light and on the sun swinging round to the north-east and north-west in high summer. The further north you go, the lower the sun sits and the weaker that effect becomes.

• Southern England (≈51°N): the highest baseline irradiance in Britain. A north-facing roof here is poor but at its least-bad — total annual figures sit at the upper end of the ranges in our table.
• The Midlands (≈52.6°N, our patch around Tamworth): close to the UK average. The figures used throughout this guide are modelled for here.
• Northern England & Scotland (≈55–57°N): noticeably lower irradiance and a lower midsummer sun, so a north-facing roof underperforms the figures above by roughly a further 10–20%. A standalone north array this far north is very rarely worth it.

None of the major solar guides break this out properly, which is a shame, because it changes the advice. The same north-west roof that is borderline-worthwhile in Surrey can be a clear no in Aberdeen. We work across the Midlands, so the numbers we quote you will be modelled for your actual postcode and roof — not a national average.

How We Calculated These Figures (Sources & Author)

How We Calculated These Figures (Sources & Author)

So you can check our working: the relative-output percentages in this guide follow the orientation and pitch correction factors published in the MCS solar PV guidance (MIS 3002 / the Standard Estimation Method), which is the same dataset accredited UK installers must use to size systems. We cross-check absolute kWh figures against the European Commission's PVGIS irradiance tool for Midlands latitudes, and validate against our own monitored installs (see the side-by-side above).

The economics assume: import price 29p/kWh, Smart Export Guarantee export 15p/kWh (around the best fixed SEG rate available in 2026), installed cost ~£1,400/kWp, 0% VAT (zero-rated to 31 March 2027, 5% thereafter), and ~25 years of generation before significant degradation. These are deliberately conservative, real-world figures — not best-case marketing numbers. Your survey will produce property-specific values.

Written and reviewed by the Midland Solar technical team — MCS-certified solar installers based in Tamworth, Staffordshire (est. 2009), designing and fitting systems across the Midlands. We have no incentive to oversell a north-facing roof: our reputation rests on systems that actually pay back. Last updated: June 2026. Questions on your own roof? Call us on 01827 218833 for a straight answer.

North-east (and north-west) facing roofs: the honest middle ground

"North-facing" covers plenty of roofs that are nothing like due north. If your ridge runs south-west to north-east or south-east to north-west, one slope points between north and east or north and west — and that changes the answer.

Why NE and NW beat due north. At Midlands latitudes the summer sun rises in the north-east and sets in the north-west, so for several months a year those slopes get direct sun early morning (NE) or late afternoon into evening (NW) rather than diffuse light alone. On the SAP annual solar radiation table used in UK building energy assessments, a north-east or north-west roof at a typical 30–45° pitch receives roughly 65–75% of the annual solar radiation of a south-facing roof at the same pitch (SAP 2009 Table H2: 785 vs 1,073 kWh/m² at 30°, about 73%; 686 vs 1,054 at 45°, about 65%); due north sits nearer 55–65%. The MCS postcode-zone dataset installers must use for a formal performance estimate puts a Tamworth-area NE/NW roof a little lower, so treat the top of that range as best-case. The edge over due north is modest — a few percentage points to around ten — but real, and shallower pitches sit nearer the top of the range (on the SAP table a steep 60° gable falls to about 60%). In kWh terms: where a south-facing 4kW system in the Midlands might make around 3,800 kWh a year, an unshaded NE or NW slope at a typical pitch lands in the region of 2,450–2,850 kWh on the SAP table, and a formal MCS performance estimate for a Tamworth postcode may come in around 10% below that — still worthwhile, but budget on the cautious end. That is better than due north, and short of the 80–85% a straighter east or west aspect gives. Try our solar calculator for a property-specific figure.

Who a north-east roof suits. Orientation shapes when you generate, not just how much. A NE slope front-loads output into the morning, which suits morning-heavy households: immersion or heat-pump cylinder, washing machine on early, home-working from 8am. More of a smaller yield gets used in-house at the import price rather than exported at the SEG rate, narrowing the gap to a south roof. A north-west slope is the mirror image — strongest late afternoon and evening, when most homes are cooking and charging.

When a split array or a battery changes the maths. A north-east roof almost always has a south-west slope on the other side of the ridge (north-west pairs with south-east). Where that pitch is usable, fill it first, then add a second string on the NE/NW side on its own inverter input (MPPT) or with optimisers, so the weaker string cannot drag the stronger one down. With scaffolding, inverter and wiring already paid for, those extra panels are the cheapest kWh you will ever add, and the two strings stretch generation from early morning to evening. If the NE/NW slope is your only option, or you are rarely home in daylight, battery storage is what makes the numbers work: it banks whatever the roof produces for use after dark, so timing stops mattering. Ask us to model it with and without a battery — that is what a free solar survey is for.