Best Solar Thermal Panels

The best solar thermal panels can help to lower the energy bills of properties with a hot water cylinder. Solar UK, Viessmann and Worcester Bosch all manufacture solar thermal panels that are worth considering. In this article we'll reveal why they're the best solar thermal panels available.

How do solar thermal panels work?

Solar thermal panels convert solar energy into heat that is then used to warm the water within a cylinder. This is contrary to solar PV panels which convert the sun's energy into electricity. There are two different types of solar thermal panel: flat plate collectors and evacuated tube collectors.

Flat plate collectors: In terms of appearance, flat plate collectors most closely resemble solar PV panels. Covering the metal tubing, which contains the fluid heated by the sun, is a flat absorber plate that's dark in colour. The benefit of having a flat plate covering the tubing is that it prevents heat from escaping.

Evacuated tube collectors: Exposed tubing separates evacuated tube collectors from flat plate collectors. Several tubes run side-by-side in a parallel line. They can either be direct flow which means that liquid in the tubes circulates down to the immersion heater in the hot water cylinder. Or, in the form of heat pipes where the fluid within the tubes evaporates and transfers the heat to the pipes in the cylinder.

Best solar thermal panels: flat plate or evacuated tube?

If how the solar thermal panels will look on your roof is your main concern then flat plate collectors are arguably the better option. Thanks to their flat dark-coloured appearance, flat plate collectors will more seamlessly fit in with the roof. Additionally, as they resemble solar PV panels, they have a familiar feel about them.

In terms of performance, evacuated tubes are capable of delivering higher year-round efficiency. When solar generation is at its peak, during the summer, both types of solar thermal panels will be equally as efficient. However, during the winter months, when sunlight is at a premium, evacuated tubes are capable of providing higher levels of hot water. This is thanks to better all round insulation.

So while flat plate collectors might be easier on the eye, evacuated tube collectors are arguably the best solar thermal panels.

Best solar thermal panel models

The best solar thermal panels are manufactured by Solar UK, Viessmann and Worcester Bosch. You'll find that there aren't as many solar thermal panels to choose between as solar PV.

Solar UK Lazer2

Solar UK is a leading name in the solar industry, manufacturing systems that are well suited to the UK climate. Reliability is a key feature of Solar UK Lazer2 solar thermal panels and they guarantee no loss of performance for 25 years.

  • Compact panels design compared with other models
  • No loss of performance for 25 years
  • Covered by a 25 year warranty
Solar UK Lazer2
Collector Type Evacuated tube collectors
Installation Above Roof
Orientation Vertical / Horizontal
Dimensions (HxWxD) 615 x 2,110 x 104mm
Aperture Area 0.932?

Viessmann Vitosol

Viessmann have taken great strides in developing renewable energy technology in recent years. They have multiple solar thermal models to choose between, including flat plate and tube collectors.

Viessmann Vitosol 100-FM

  • Reduce energy bills by as much as 30%
  • Provide central heating back-up
  • ThermProtect absorber layer which prevents the collector from overheating
  • Models for all types of installation including above roof, roof integration, flat roof installation and wall mounting
Viessmann Vitosol 100-FM SV1F
Collector Type Flat Plate
Installation Above Roof
Orientation Vertical / Horizontal
Dimensions (HxWxD) 2,380 x1,056 x 72mm / 1,056 x 2,380 x 72mm
Aperture Area 2.33?
Efficiency 80.3%

The Viessmann Vitosol range also includes SH1F models which have been designed for roof integration.

Viessmann Vitosol 200-FM

  • Panels can be installed horizontally or vertically for flexible installation
  • They avoid overheating
  • Features a ThermProtect absorber layer for increased efficiency
  • Can be installed onto a wall when roof installation isn't possible
Viessmann Vitosol 200-FM SV2F
Collector Type Flat Plate
Installation Above Roof
Orientation Vertical / Horizontal
Dimensions (HxWxD) 2,380 x1,056 x 90mm / 1,056 x 2,380 x 90mm
Aperture Area 2.33?
Efficiency 81.3%

The SV2G models have been designed for installation within the roof as opposed to the SV2F panels which are placed on top of the roof.

Viessmann Vitosol 200-FM SV2G
Collector Type Flat Plate
Installation Roof Integrated
Orientation Vertical / Horizontal
Dimensions (HxWxD) 2,394 x 1,070 x 90mm / 1,070 x 2,394 x 90mm
Aperture Area 2.33?
Efficiency 81.3%

Viessmann Vitosol 300-TM

  • Designed for long lifetime
  • A Duotec double pipe heat exchanger delivers maximum heat transfer
  • Thermal insulation limits heat loss
  • Adjustable pitching angle of +/-25°
Viessmann Vitosol 300-TM
Collector Type Flat Plate
Installation Above roof
Orientation Vertical
Dimensions (HxWxD) 2,241 x 1,053 x 150mm
Aperture Area 2.33?
Efficiency 81.4%

Worcester Bosch Greenskies

Like Viessmann, Worcester Bosch are well known in the UK for their boilers but have been making moves into renewable energy too. In addition to their Greenskies solar thermal panels, they also manufacture air source and ground source heat pumps.

Worcester Bosch Greenskies flat plate solar thermal panels are designed for domestic installation.

Worcester Bosch Greenskies Lito

  • Lightweight collectors of only 30kg
  • Available with a 10 year product warranty
  • MCS Solar Keymark certified
Worcester Bosch Greenskies Lito
Collector Type Flat Plate
Orientation Vertical
Dimensions (HxWxD) 2,017 x 1,175 x 87mm
Aperture Area 2.25?
Efficiency 76.6%

Worcester Bosch Greenskies Lifestyle

  • The most efficient solar thermal flat plate collector panels
  • A versatile range of solar panels that can be installed on a roof, within a roof or on a wall.
  • Leading thermal heat loss coefficient of a1
  • Vertical and horizontal design for flexible installation
  • 10 year product warranty
Worcester Bosch Greenskies Lifestyle (Landscape)
Collector Type Flat Plate
Orientation Horizontal
Dimensions (HxWxD) 1,175 x 2,017 x 87mm
Aperture Area 2.25?
Efficiency 76.6%

The vertical Greenskies Lifestyle panels have very similar specifications to the horizontal panels. However, slight differences can be found in the dimensions and efficiency.

Worcester Bosch Greenskies Lifestyle (Vertical)
Collector Type Flat Plate
Orientation Vertical
Dimensions (HxWxD) 2,026 x 1,032 x 67mm
Aperture Area 2.25?
Efficiency 75.6%

How much do the best solar thermal panels cost?

Green Homes Grants

Under the government's Green Homes Grants scheme, between September 2020 and March 2021 you can apply for a grant to cover two-thirds of the cost of installing solar thermal panels.

Many UK homeowners want to reduce their heating bills and carbon footprint by installing solar thermal panels, but most do not have the money available to cover the upfront costs. To address this, the government is introducing the Green Homes Grants scheme which will give UK homeowners up to £5,000 (£10,000 for the lowest income households) towards the cost of installing a solar thermal heating system.

The cost of a solar water heating system will vary depending on the system size needed to meet the hot water demands of your home. It's widely recommended that 1m2 of solar thermal panel is needed for each person in the home. This would mean that a family of 4 should have a 4m2 sized solar thermal system on the roof. And this would likely cost between £3,700 and £4,200.

Solar thermal installation prices will vary depending on the complexity of the installation and size of the system being installed. Solar companies all have their own rates too, which makes it very important to compare quotes.

Why install a solar water heating system

Having a solar water heating system installed comes with many benefits. The main advantage being that rather than relying on energy from a supplier, you're generating it yourself.

Each year, solar thermal panels can account for up to 70% of a home's hot water demand. Naturally, solar panels are at their most effective during the summer months. This is thanks to the longer daylight hours. So a solar thermal system will meet more demand for hot water in the summer than during the winter.

Percentage of Domestic Hot Water Supplied by Solar Thermal per Season
Summer 80 – 90%
Autumn and spring 40 – 50%
Winter 20 – 30%

Source: Worcester Bosch

More benefits of a solar thermal system include:

  • Less energy will need to be delivered to your property from the energy supplier, lowering your energy bills
  • Receive government payments through the Renewable Heat Incentive (RHI)
  • Heating the water in a cylinder with clean renewable energy will help to lower your carbon footprint
  • Once installed, there are no running costs to worry about, the solar thermal panels will just get on with heating the water in your cylinder
  • Very little maintenance is required with a professional service every 3-5 years being sufficient

If you’re unsure whether to have solar thermal or solar PV installed then our comparison article will help you decide: Solar PV vs Solar Thermal.

Finding a solar installation company

As well as installing the best solar thermal panels, you'll want to hire the best solar installation company. And the best way to do this is by comparing multiple quotes.

At Solar Guide, we have a network of solar installation companies right across the UK. To connect with those local to you all you have to do is complete our simple online form. We'll ask you a few straightforward questions about the work you need carrying out. Then we'll use the information you provide to match you with up to 3 companies qualified to complete the work.

Each company will provide a quote for the installation of a solar thermal system for you to then compare. Best of all, it's completely free and there's no-obligation whatsoever.

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