CAN YOU USE SOLAR PANELS TO POWER UNDERFLOOR HEATING?

Our energy expert dives into the maths to answer the question of whether solar power alone is sufficient for your underfloor heating

- DAVID HILTON

With increasing energy bills, it's not uncommon to look at renewable energy, such as solar panels, as away of reducing costs. Despite the initial investment, it can pay dividends in the long run, reducing energy bills and improving your carbon footprint.

But is it ever possible to pinpoint exactly what the energy from your solar panels can and can't heat? I often get asked if solar panels and underfloor heating used together means you are essentially generating free heat.

In its simplest form it seems like the ideal marriage: free solar electricity and therefore free heating. But unfortunately this does not work in reality, and here are the reasons why.

HOW MUCH ENERGY DO SOLAR PANELS PRODUCE?

At its peak, the sun can deliver around 1000W of power per square metre. But this is only really achievable for a very short amount of time per year. The way solar panels work is that the sun needs to be bright, at 90 degrees (perpendicular) to the panel, with no clouds in the sky and a gentle breeze to cool the panels down.

In reality we get an average of around 5000W of power per square metre per day in summer, which drops to around 800W per square metre in winter. On average, homes have around 20 square metres of panels on a roof, and the panels are around 20% efficient.