Residential voltage optimisation case study: 4 sites to 14 across the UK. 1,118,879 kWh saved so far.

This residential voltage optimisation case study follows a UK residential living operator that first spoke to Powerhub Solutions in 2023, looking to lower electricity use across its buildings without disrupting residents or adding work for its site teams. 3 years on, voltage optimisation is running at 14 of its sites, and the portfolio has saved 1,118,879 kWh of electricity to date.

The energy challenge in residential buildings

Residential buildings use electricity around the clock, from communal lighting and plant to shared spaces that never fully close. That constant demand makes energy one of the largest controllable costs in the portfolio, while also making it difficult to cut, because any measure that affects comfort or requires residents to change their habits is unlikely to hold.

The operator needed a saving that would run in the background, apply to every piece of equipment on site and keep working without ongoing management.

How voltage optimisation reduced electricity use

UK sites are frequently supplied at a higher voltage than the equipment inside them is designed to use, and that excess is lost as heat, noise and wear. Voltage Optimisation brings the incoming supply down to the level your equipment actually needs, which reduces consumption across the whole site at once.

Powerhub Solutions began with 4 sites, installed in July and August 2023, sized individually to each building’s supply. Our own engineers carried out every installation, and savings at each site have been measured and verified against its baseline consumption.

Residential voltage optimisation results

The first 4 sites have saved 760,062 kWh between them, which accounts for 68% of the portfolio’s total saving. The largest of those sites has reduced its electricity use by 8.51%, the highest reduction across the portfolio.

With those results in hand, the operator extended the rollout, adding 9 sites during 2025 and 1 more in 2026. Every one of the 14 active sites is now using less electricity, with individual reductions ranging from 6.23% to 8.51%.

Figures are to September 2026. Energy cost savings are calculated at 20p per kWh, and carbon savings use the UK Government’s 2024 greenhouse gas conversion factor for electricity.

Why the operator rolled out to 14 sites

The earliest sites have now been running for over 3 years, which gives a clear record of how the savings hold up across changing seasons and occupancy. The sites added in 2025 and 2026 are already showing reductions in line with the originals, so the result has proved repeatable across buildings of different sizes and in different parts of the UK.

For a portfolio operator, that consistency matters as much as the headline number, because it turns a single project into a standard that can be applied to every new building.

Energy saving solutions for your buildings

If your sites run continuously and your equipment is supplied at a higher voltage than it needs, the same saving is likely to be available to you. A voltage survey is the starting point, showing what your sites are currently receiving and what reduction is realistic before any commitment is made.

Voltage optimisation sits alongside the other energy saving solutions Powerhub Solutions delivers with its own engineers, including the Pulse Energy Management System, KBR Energy Saver for commercial refrigeration and solar PV and battery storage. The results in this residential voltage optimisation case study are a useful benchmark when you compare the options for your own portfolio.