Solar and battery storage could save more cash than high-interest bank accounts

Home solar and battery systems could deliver stronger long-term financial returns than high-interest savings accounts, according to modelling by installer Fit Solar.

The analysis compared an £8,500 solar and battery system with £8,500 held in a savings account paying 4.5% annual interest. For a household using 3,500kWh of electricity a year, the model estimates the system would pay for itself in around 8 years and overtake the savings account in year 13.

After 25 years, the model puts the value of the solar investment at around £46,700, compared with £25,500 in the savings account, assuming savings are reinvested at 4.5%.

The modelling suggests rising electricity prices could shorten the payback period. Using Cornwall Insight’s forecast of a 16% increase in the energy price cap in January 2027, payback falls to around 7 years.

However, returns depend on factors including household electricity use, roof orientation, shading and export tariffs. The system is also less liquid than cash savings and may require inverter or battery replacement during its lifetime.

The analysis also assumes the current 0% VAT rate for domestic solar before its scheduled end in March 2027.