A London landlord tired of handing his margin to the grid
Karan Buttar owns two residential towers in London, Tower A with 33 flats and Tower B with 31. Being a landlord in the city can be a slow financial bleed, and the landlord supply bill, the power for the shared parts of a block, is a big part of it. Karan wanted two things at once. Lower running costs, and modern, more energy-efficient buildings that would be worth more and easier to let. Solar could do both, so he came to us. The catch was that he didn't want to solve it one tower at a time.
Get the same result on two buildings, not one
A single rooftop system is straightforward. Two, at once, that have to perform the same way and pay back on their own, is a different job. Karan's plan was to replicate one proven design across both towers so the returns were predictable rather than a gamble. Both roofs were flat and shallow, a 10° pitch, so the layout had to work hard to squeeze a strong yield out of a low angle. Size it wrong on either building and one tower quietly drags the whole investment down. He needed a system big enough to move a real landlord-supply bill, built the same way twice.
One high-performing design, replicated across both towers
We didn't reinvent the wheel for each building. We designed one system that made the most of a south-facing flat roof, then built it twice, 15.23 kWp on each tower. South orientation and modern three-phase inverters keep the yield strong across the year, even off a shallow roof. We ran both jobs end to end, from site visit and design through to install and commissioning. The combined total came to £28,800, which is £14,400 a tower.
- 70 × Jinko 435W panels (30.46 kWp total, split evenly across the two towers)
- 2 × Solis 15kW 3-phase inverters, one per building
- South-facing flat roofs at a 10° pitch, laid out for a strong low-angle yield
- The same proven design replicated on both towers for predictable, repeatable returns
Nearly half the landlord supply, made on the towers' own roofs
The two systems now generate about 33,500 kWh a year between them. That covers roughly 45% of the landlord supply, straight off the roofs. In cash it works out at about £6,000 to £6,600 off the bill every year, close to £550 a month, and £150,000 to £165,000 across the systems' 25-year life, with the full £28,800 paid back in about six to eight years. After that the shared power is close to free, on two buildings that are now cheaper to run and worth more to hold.
Generation and saving figures on this page are estimates, modelled from the system size and a typical UK yield. They are not meter readings. Your own figures depend on your roof, your usage and the weather in any given year, and we confirm them from a real assessment rather than a model.
