St Joseph's Care Home is quoted to save £16,123 in its first year from a 67.34 kWp rooftop solar system designed by Spirit Energy. The system is forecast to generate 57,727 kWh a year, covering roughly 32% of the home's electricity use. At a 22% internal rate of return and a five year payback, it sits inside the range Spirit Energy has modelled across its wider care home portfolio.
Care homes are one of the few commercial building types with no meaningful low-demand period. Kitchens, laundries, hot water, heating, nurse call and life-safety systems run continuously, and occupancy does not drop at weekends.
The roof is the constraint, not the budget. St Joseph's has a pitched tile roof arranged so that the usable area faces three different directions, and the total space supports 67.34 kWp. On the quote's own assumptions, that covers about 32% of what the site draws. The remaining 68% still comes from the grid.
Partial coverage tends to be read as a reason not to proceed. It is worth separating two things: the share of demand a system covers, and the return the system makes. They are not the same number, and on a 24/7 site they diverge sharply in the owner's favour.
Spirit Energy split the installation across the three usable roof planes, oriented 28°, 62° and 118° from south, each at a 35 degree pitch with no shading recorded. The array closest to due south carries 28.21 kW and produces 27,025 kWh a year on its own. The 62° array contributes 18,544 kWh from 20.93 kW, and the 118° array 12,158 kWh from 18.2 kW.
The system uses 148 Trina Vertex S+ 455W panels, giving an active cell area of about 296 m². They are mounted on brackets fixed to the rafters with over-roof mounting frames, using a K2 concrete tile system. Scaffolding, edge protection and lifting are included in the price.
All three arrays feed a single Solis-50k-S5 inverter, located in a top floor riser cupboard so the plant stays out of circulation areas. That puts 67.34 kWp of DC capacity behind 50 kW of AC output, a ratio of about 1.35 to 1. The three orientations peak at different points in the day rather than together at midday, which spreads the output curve rather than concentrating it.
Because the system sits above the threshold for network approval, it requires prior permission to connect from the Distribution Network Operator. Spirit Energy handles that application in-house as part of the feasibility stage, alongside the structural survey and technical survey. DNO applications typically take 6 to 13 weeks to process, which is usually the longest single item in a commercial solar programme.
First year benefits are modelled at £16,123. That breaks down into £15,214 of avoided grid purchase, based on 79% of generation being used on site plus £909 of export income on the remaining 21% at an assumed rate of 7.5p/kWh.
On those assumptions the payback period is 5 years and the internal rate of return is 22%. Net present value of savings and income over the modelled life is £305,822. Cumulative savings after 20 years, net of maintenance, come to £407,052.
Those figures rest on a 5% annual increase in the value of displaced electricity, 0.7% annual panel degradation and a 2% discount rate. Import and export rates both track wholesale markets, so the model is an approximation rather than a guarantee.
The system is forecast to save 12,989 kg of CO2 in year one, just under 13 tonnes, against grid electricity. That figure declines slowly over the system's life as panel output degrades and as the grid itself decarbonises.
Ashlyns Care Home, also designed by Spirit Energy, covers around 70% of its site demand and returns 19% IRR over a six year payback. St Joseph's covers 32% and returns 22% over five. The share of load a roof can carry is largely fixed by the building. The return is set by how continuously the site uses electricity, and care homes use it continuously.
For an operator, that means a modest roof is not a reason to rule solar out. A system that covers a third of the bill on a 24/7 site is a better financial proposition than one covering two thirds on a building that empties at six o'clock. Spirit Energy has recorded 19 to 30% IRR and 3 to 6 year paybacks across its care home portfolio in the UK, on sites ranging from 28 kWp to over 130 kWp.
Once the payback period ends, the generation continues for the remaining life of the panels at close to zero marginal cost, and it belongs to the operator rather than to a supplier contract.
If you would like to learn what solar could do for your care home, get in touch: commercial@spiritenergy.co.uk