Solar Thermal v's Solar PV: Why Solar Water Heating is the Smartest Choice
Prioritizing Solar Water Heating for Maximum Efficiency
When investing in solar energy, the first step should always be solar water heating. Why? Because water heating, swimming pools, and underfloor heating are some of the biggest energy consumers in homes and businesses.
Instead of relying on expensive electric heating, a solar thermal system can deliver free, renewable heat directly from the sun—far more efficiently than solar photovoltaic (PV) panels.
The Efficiency Gap: Solar Thermal vs. Solar PV
Many people assume that more solar PV panels automatically mean better energy efficiency—but that’s not true when it comes to heating water;
– Solar thermal converts up to 90% of sunlight into heat
– Solar PV converts only around 23% of sunlight into electricity
Why Solar Water Heating is Far Superior to PV for Heating Water:
More Efficient – Solar thermal panels capture up to 7x more energy than PV panels when used for water heating.
Takes Up Less Roof Space – A small solar thermal system can heat most of your hot water needs, while a PV system would need significantly more panels to generate the same amount of energy.
Performs Better in High Temperatures – Unlike PV panels, which lose efficiency as they heat up, solar thermal panels work best in strong sunlight.
Lower Cost, Faster Payback – Solar water heating systems generally cost less than a PV system and offer a quicker return on investment.
The Problem with Using PV for Water Heating
Many people think they should install as many solar PV panels as possible, but this is not always the best approach. Here’s why:
– PV panels lose efficiency in heat – High temperatures can reduce PV output by 10-25%, making them least efficient during peak sunlight hours.
– Using PV to heat water is wasteful – Converting sunlight → electricity → heat is far less efficient than simply using solar thermal panels to heat water directly.
– You’ll need extra PV panels – If you rely on PV to power electric water heating, you’ll consume more electricity, requiring extra panels and larger battery storage.
A Smarter Solar Strategy: Go Solar Thermal First!
The smartest approach to solar energy:
Install a solar water heating system first – Reduce your electricity demand by heating your water directly with solar thermal panels.
Then assess your PV needs – Once your biggest energy demand (hot water) is covered, you can size your PV system correctly instead of overspending on unnecessary panels.
Bottom Line: Solar Water Heating is the Best Choice
– It makes no sense to use electricity to heat water when solar thermal is far more efficient.
– Solar thermal panels capture more energy, require less space, and cost less than a PV system for heating water.
– With lower upfront costs and faster payback, solar water heating is the best investment for homes, hotels, pools, and commercial buildings.
For those serious about reducing energy costs and going green, solar thermal should always be the first choice for water heating.