Solar Thermal vs Solar Panels

People say "solar" as if it is one thing. It is two. Solar thermal captures the sun as heat. Photovoltaic panels, PV, convert the sun into electricity. For heating water or a pool, that difference decides everything.

The core difference

Solar thermal collectors turn sunlight directly into heat and move that heat into water. Photovoltaic panels turn sunlight into electricity, which can then, less efficiently, be used to run a device that makes heat. When the job is heat, going straight from sun to heat skips a lossy conversion step.

Efficiency for heating

For the specific task of heating water or a pool, solar thermal is far more efficient per square foot of roof than using PV to power a heater. A thermal collector can turn a large share of the sunlight that hits it into usable heat. PV converts a much smaller share into electricity, and you then lose more turning that electricity back into heat.

When each makes sense

Choose solar thermal when

• You want to heat a pool or domestic hot water
• Roof area is limited and you want the most heat per square foot
• You want the fastest payback for a heating load

Choose photovoltaic (PV) when

• You want to offset household electricity use
• You want to power general loads, not just heat
• You are pairing with batteries or an electric vehicle

Why the thermal trade faded

PV got the subsidies, the headlines, and the sales machine. Solar thermal, older and in many heating cases more efficient, was quietly abandoned by an industry chasing the electric story. Rebuilding that trade is the reason this project exists.