Solar water heating, also known as solar thermal, uses energy from the sun to heat water to between 60°C to 80°C, this can then be stored in a tank ready for on-demand, domestic use.
It is a cost-effective and climate-friendly way to heat water to meet domestic hot water needs.
Since the system uses sun rays to heat water, it is essentially free – minus the initial installation costs obviously.
However, realistically a solar water heater can only meet around half of your annual hot water demand in the UK.
Solar Water Heating UK Key Points:
- Solar water heating uses energy from the sun to heat water for your home.
- Systems have solar collectors, a storage tank, and a pump.
- There are two types of collectors: flat plate and evacuated tube.
- Benefits include cost savings and environmental friendliness.
- On average, they can meet around 50% of a home’s annual hot water demands in the UK.
- UK effectiveness depends on system size, roof orientation, and shading.
- Government incentives like RHI can help offset costs.
- Choose a reputable installer and maintain the system.
- Other options for reducing energy bills and carbon footprint include insulation, energy-efficient appliances, and renewable electricity.
How Does Solar Water Heating Work?
There are three main components of solar water heating which are as follows:
- #1 Solar collector.
- #2 Controller unit that manages the pump.
- #3 Hot water cylinder with two heating coils.
The solar collectors gather solar energy which heats up the fluid inside it.
The pump managed by the controller unit circulates the fluid around the circuit and heats up the water cylinder.
Top-up heating is required in winter or bad weather conditions.
To cope with such situations, a cylinder with two heating coils is essential that allows top-up heating which can be done from a conventional boiler or any other renewable energy option.
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1. Solar Water Heating Collectors
There are two main types of solar water heating collectors i.e. evacuated tubes and flat plate collectors.
These look like some fancy fluorescent lights that have been assembled side by side. Each tube is made up of two glass tubes that have been separated by an insulating vacuum space.
The evacuated tubes receive the concentrated solar energy and send it to the combined heat exchanger. The vacuum designs ensure very effective thermal insulation.
These look like water pipes running through the thick back glass. The glass traps the heat which is then transferred to your water tank through the water pipes.
2. Controller Unit
A control system usually comprise a pump, flowmeter, thermostat and pressure gauge. The control system is attached to the solar thermal panel with a valve.
A valve can switch off the water circuit on cold days.
3. Hot water Tank
A hot water tank is required to store heat-up water.
The size of the hot water tank is entirely dependent on the size of the family and their hot water usage.
Typically a hot water tank for a family home is about 100-200 litres (30-60 gallons).
Benefits of solar water heating
There are many benefits of solar water heating but the three main benefits include hot water supply all year round, reduced electricity bills and lower Carbon footprint.
1. Hot water supply throughout the year
The system works all year round however you need to have top-up heating during the winters or dark cloudy days.
This top-up can be done from a conventional boiler or any other renewable energy option.
A solar water heating system can meet 90% of your hot water demand in summers while can only meet 25% of your demand in winter.
This clearly emphasizes the need for an efficient back-up system.
2. Reduced Energy Bills
Since the Solar heating system uses sunlight to produce hot water, it is completely free. This can lead to a significant reduction in your energy bills.
3. Lower Carbon Footprint
The solar water heating system doesn’t use any fossil fuels to produce hot water. It is a completely renewable form of energy hence reducing your carbon footprints.
Solar Water Heating Costs and Savings
The average cost of a standard solar water heating system is around £3,000 to £5,000.
The cost is usually dependent on the type of system you choose to install i.e. evacuated tube or flat plate collectors.
The savings you make from a solar water heating system varies throughout the year.
For example, you tend to have more savings in summers when up to 90% of your hot water demand is met through this system and you need a less frequent top-up.
On the contrary, you will be having fewer savings in winters when the hot water demand is high and the system can only meet 25% of your need.
You will require top-up more frequently hence the savings in winters will be less than the savings in summers.
Solar water heating can save up to £95 a year from a solar water heating system if your existing system is gas, £150 if the existing system is oil and up to £200 if the existing system is LPG.
Quick help guides:
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Do solar water Heaters work in the UK?
As mentioned above, a solar water heater can meet more than half of your annual hot water demand even in cloudy British weather.
This means it saves a considerable amount from electricity bills throughout the year.
For example, in a household where all family members take bath, especially in summers, solar heating definitely makes sense.
However, of all the hot water it generates throughout the year, most of it is in summer.
In winter, solar water heating only produces a small amount of hot water which is not enough to meet the hot water requirement on cold days and a top-up from another system is required to fulfil the hot water demand of households.
Since British weather is cold most of the year, the reliance of solar water heating systems on any other heating system for top-up is huge. So the savings in terms of energy bills in winter are not great.
Also, you can only install solar water heating panels if your house is ideally south facing, or at least between East or West.
By any chance, if your house is north-facing, your panels will not be able to absorb enough amount of sunlight to store energy and will be nearly useless.
Do you need planning permission?
Generally, you don’t require planning permission to install solar water heating panels at your home.
However, it is best to check for exceptions from your local planning office.
For example, you may require planning permission if your home is a listed building or in a conservation area.