Solar Thermal Collectors

While Solar PV system turn the sun’s energy directly into electricity, solar thermal panels harness the sun’s energy by turning the solar radiation into heat. This heat is normally then used to heat water for use in the home.

At the heart of every solar thermal system is the collector. We recommend and install evacuated tube solar collectors.

The evacuated tube solar collectors are the most efficient with a conversion efficiency of over 70%. This means that they can produce more heat, so while a simple plastic collector might be fine to help keep a swimming pool warm – if you want to produce hot water to use in your radiators then ideally you are going to need to go with one of these.

We believe the Barilla TZ Solar Thermal Evacuated Tube system is the best value for money you can buy. Here's why:
  • High performance evacuated tube collectors
  • Available in 10, 15, 20, 25 and 30 panels
  • Can be mounted free-standing or on a pitched roof
  • Solar keymarked and EN12975-2 certified
  • Heat pipes - offer low maintenance
  • Easy to install, simple roof fixings
  • 10 year warranty, 20+ year lifespan
  • Radial absorbers enhance morning and afternoon output

Technical Specification

Zero Heat Loss Efficiency,n0: 73.4%
Primary Heat Loss Coefficient, a1: 1.529 Wm2K
Primary Heat Loss Coefficient, a2: 0.0166Wm2K2
Incident Angle Modifier, K150°: 1.37
Instantaneous Efficiency**, n0.05a: 62.4%
Specific Output:* over 620kWh/m2/year
Stagnation Temperature: 200.3°C
Maximum Operating Pressure: 10 bar
Collector Frame and Manifold: Aluminium
Selective Absorber Coating: CerMet
Absorber Contact Sheet: Aluminium
Evacuated Tube: Borosilicate Glass 1800mm x 58mm (OD) x 47mm (ID)
Tube Spacing: 8mm
Testing & Certification: EN12975-2 & Solar Keymark Registration No. 011-7S722 R

*Based on a collector located in Southampton, UK in an unshaded position facing South and tilted at 45°.

** Based on 800 W/m2 irradiation and 40°C temperature difference between ambient air and collector.


The Renewable Heat Incentive (RHI) is a UK Government scheme set up to encourage the uptake of renewable heat technologies among householders, communities and businesses through the provision of financial incentives. It is designed to reward households that move away from fossil fuels by paying them to generate heat from renewable sources, such as a solar thermal evacuated tube system.

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