Why pig units & finisher houses are an excellent fit for commercial rooftop PV
UK pig finisher houses and farrowing units have some of the most consistent commercial electrical demand profiles we encounter on working farms — climate-controlled finisher houses run continuous ventilation, heating in cold months, and lighting around the clock; farrowing houses add creep heating, infrared lamps, and feed-system pumps. Modern indoor pig operations to Red Tractor Pork and RSPCA Assured standards typically run 3–6 climate-controlled finisher houses on a single yard, each 60–80 metres long and 14–18 metres wide. The aggregate baseload is significant and well-aligned to PV generation — most pig finisher installs achieve 80–90% self-consumption ratios. Outdoor and free-range pig operations have lower baseload but typically still support 40–100 kW per building roof.
System sizing for pig units & finisher houses
Pig unit PV sizing: indoor finisher houses with climate control typically support 60–120 kW per building roof (depending on roof area), with strong self-consumption thanks to continuous ventilation and lighting baseload. Farrowing houses with intensive creep heating in cold months can support similar capacity. Multi-building intensive operations often support combined installs of 200–500 kW. Outdoor pig operations sit at the smaller end, typically 30–80 kW per building. Many UK pig operations also run biogas/anaerobic digestion (AD) infrastructure on the same yard — PV complements rather than competes with AD, since AD typically runs on slurry-derived gas while PV captures rooftop solar resource that would otherwise be unused.
Typical pig units & finisher houses install at a glance
- System size range
- 40–250 kW
- Panel count
- 75–460
- Roof area needed
- 250–1,500 sqm
- Annual generation
- 37,000–230,000 kWh
- Annual CO2 avoided
- 9–53 tonnes
Cost and economics
Pig unit install economics in 2026: 40–250 kW typical systems, 37,000–230,000 kWh annual generation.
Compare these numbers against the wider cost of farm-building solar in 2026 and the grants and finance routes available. Ask each installer to show its yield and financial assumptions in writing, and compare them with the farm solar payback calculator.
On a finisher house the ventilation load is the number that matters: use the farm solar payback calculator to estimate the payback for this roof from your bills.
Compliance and regulation
African Swine Fever biosecurity (Pig Health Scheme, AHDB protocols) is observed throughout install — boot dips, restricted vehicle access, full crew decontamination, AHDB-approved access permissions. NVZ slurry-management and water-protection compliance unaffected by rooftop PV. Welfare of Farmed Animals Regulations 2007 unaffected. Red Tractor Pork and RSPCA Assured schemes welcome PV. Listed buildings are uncommon in pig units (most are post-1970 builds) but where present require Listed Building Consent. Modern climate-controlled houses with sealed ventilation systems require careful coordination of cable penetration to maintain biosecurity integrity.
Install programme and timeline
What an install involves: a structural and electrical survey, a design and written proposal, the DNO G99 application, procurement, installation and commissioning. Ask each installer for its programme in writing; the grid connection is usually the longest step, so apply early. See the planning guide for the Class J limits.
A modelled pig units & finisher houses scenario
A typical modelled scenario: a south Shropshire indoor pig finishing operation processing 4,500 finishers at peak across three climate-controlled finisher houses each 80m × 18m. Annual pre-install electricity spend £74,500 across continuous ventilation, climate control, feed-system pumps, and farrowing-house creep heating. The modelled scope: 240 kW rooftop PV across all three finisher house roofs — 440 modules, three string inverters, integrated with auto-changeover to protect critical ventilation load. A project like this observes full African Swine Fever biosecurity protocol throughout install. The modelled system reaches 86% self-consumption thanks to year-round high ventilation and lighting baseload. Modelled annual saving: £52,000 in year one. Simple payback 5.8 years. For a retailer-supplying operation, the install feeds Scope 2 evidence straight into the supplier review.
More modelled worked examples are in the case studies library; each is labelled as modelled, not a named client project.
Key features and capabilities for pig units & finisher houses
- Climate-controlled finisher houses have high year-round ventilation and heating loads
- Farrowing-house heat lamps and creep heaters major winter loads
- Often paired with biogas/AD on intensive sites — PV complements rather than competes
- Red Tractor Pork and RSPCA Assured scheme alignment
Send your pig units & finisher houses roof details
Tell us the building, the roof sheeting and what you want to know. Send your details through the quote form and we reply by email. Before you sign with any installer, check their MCS certificate on the MCS register and ask for the structural, roof-condition and grid assumptions in writing.
Common questions
How much do solar panels for farm buildings cost in the UK?
DESNZ's solar PV cost data for 2025/26 puts the mean installed cost of 10-50 kW projects at about £1,267 per kW (median about £1,204 per kW), and non-domestic 10-50 kW installations at about £1,167 per kW. The series covers all building types, not farm buildings alone, and stops at 50 kW. Your price depends on roof access, any re-roofing, cabling distance to the intake and the grid connection. The cost page on this site sets out the regional figures and the method; treat them as a benchmark and compare written quotes against them.
Can we put solar panels on asbestos cement barn roofs?
Not directly: installers will not normally fix through asbestos cement sheets, so the roof is overclad or replaced before the panels go on. HSE says most work on asbestos cement is non-licensed provided the people doing it are informed, instructed and trained, and its task sheet A14 asks whether the sheets can be overlaid with non-asbestos material instead of removed. Price the roof work and the PV separately: the roof is building fabric, the PV is plant, and the two are treated differently for tax.
Which farm building should we install solar on first?
Prioritise by three criteria: (1) roof area and orientation — the biggest south-facing clear-span roof in sound structural condition wins; (2) on-site daytime load — dairy parlours, grain stores during harvest, intensive livestock houses, and farm workshops all have year-round or seasonal daytime baseload; (3) install access and biosecurity complexity — workshops and grain stores typically have lower biosecurity friction than poultry or pig units, but the latter often have much larger roofs. We rank each building during feasibility on payback, self-consumption, and complexity.
Will solar panels work on a curved or arched barn roof?
Generally no — modern PV requires a structural surface with adequate purlin spacing and slope (typically 5° to 35°). Curved Dutch-barn or hooped sheds need either a separate flat or pitched roof to be installed (rare), a ground-mount alternative, or — most commonly — a different building on the farm chosen as the PV host. We assess every farm holistically rather than fixating on a single building.
What grants are available for farm-building solar in 2026?
No capital grant for rooftop solar on farm buildings was open in England, Wales, Scotland or Northern Ireland when checked on 3 November 2026. What does apply: the 100% Annual Investment Allowance on the PV plant (UK-wide; solar is special-rate plant), Smart Export Guarantee income in Great Britain (Northern Ireland has no SEG; suppliers there set their own export rates), and the Workplace Charging Scheme if EV chargers are part of the project. The Sustainable Farming Incentive pays for land-management actions, not solar. The grants and funding guide sets out each nation and the alternatives when no grant fits.
Do we need planning permission for solar on agricultural buildings?
Rooftop solar on a non-domestic building such as a farm shed is usually permitted development under Class J of Part 14 of Schedule 2 to the GPDO 2015, inside its physical limits. Above 50 kW you must apply for prior approval on design, appearance and glare. Listed buildings and some designated land are treated differently, and ground-mounted arrays follow other rules. The planning guide on this site sets out the current rules; confirm with your local planning authority before you commit.