Getting the best saving from Solar

With the uplifted Approved Document L, the upcoming Future Homes Standard, and the drive towards net zero, there has been a significant increase in demand for low-energy and renewable technologies, such as photovoltaic systems.

All new homes are required to have a specific level of energy efficiency and there are opportunities in the retrofit market, as local authorities seek to improve the energy efficiency of the UK’s ageing housing stock. Meanwhile, soaring bills are a catalyst for homeowners wanting to cut costs. So how can solar roof tiles achieve the best savings?

Sizing and controls for a solar roof tiles

The first step is sizing the system correctly. A well-sized solar PV system can cover a significant proportion of a home or building's annual electricity usage, up to 65-75% in many cases, and cut carbon emissions by around 15%.

Solar roof tiles only produce electricity during sunlight hours. So, as well as educating customers about the best way to use electrical appliances, contractors can also add value with technological solutions that prevent generated electricity from being lost back into the grid.

At our Red Lane project in Disley, Marley SolarTiles® were installed in a new-build property, providing a source of renewable energy. The installers noted the importance of a control system to ensure that unused energy from the solar roof tiles is utilised in the most cost-effective way.

"We have provided monitoring portals for the customer so they can see how much electricity they are generating. The whole system provides enough energy to power the house, maintain battery levels for future electricity use and return electricity to the National Grid," they explained.

Solar roof tile positions and efficiency

The position of a solar roof tile can play a big part in the savings achieved. While solar roof tiles pointing in any direction will provide electricity, south-facing roofs are ideal, as they will get maximum sunlight. Sources of shading should also be considered and avoided.

There’s also the efficiency of the panels to think about. When we were installing solar panels back in 2010, they were probably 200 watts or 220 watts peak per panel. Now, for the same size panel, we’re seeing 50% more power out of the same area. When choosing PV systems, remember that monocrystalline panels have higher efficiencies and our Marley SolarTiles® have been designed to generate even more electricity per panel, meaning that 1kWp can be fitted in just 45 minutes.

Pairing solar roof tiles with batteries

Incorporating battery storage is another way to maximise savings. Selling unused energy back to the grid was once seen as a more lucrative option, but energy companies now pay such lower amounts that it’s more cost-effective to pair solar roof tiles with battery systems. Meanwhile, battery storage technology is becoming more and more affordable due to the large-scale investment in UK battery plants for electric vehicles.

Battery storage is particularly useful if occupants are out of the home during the day when the solar tiles are at their maximum productivity. It can also reduce the cost of at-home charging of electric vehicles.

As well as storing energy from the solar roof tiles during the day, batteries can be charged overnight on a lower electricity tariff and then this power can charge electric vehicles, or any other electrical appliance in the house, including heat pumps.

Solar roof tiles combined with power diverters

If customers don’t have the budget for a storage battery, then a PV power diverter is a cheaper option that can also help increase solar savings.

The power diverter detects when the PV system is generating more electricity than the occupier can use and will switch something on in the house. This could be an immersion heater in a hot water tank for instance. This way, rather than it being lost into the grid, they can keep the electricity in the house and use it to heat up hot water to use in the evening.

Maximising solar roof tile use: occupier behaviour and solar energy monitoring

Once the solar roof tiles are installed, along with any ancillary equipment such as batteries and diverters, it’s down to the building occupants to ensure that the energy generated is used in the most cost-effective way possible.

The updated Approved Document L requires operating and maintenance instructions to be provided to the owners of a dwelling for any on-site electricity generation. These instructions should provide details to help occupiers achieve the expected energy efficiency of the property.

In addition, building occupants need to be aware that there are simple behavioural changes that can help them optimise savings from solar roof tiles. This can include setting timers while they are out at work so that appliances come on in the daytime. Also, it is best to stagger the use of high wattage appliances, such as the washing machine and dishwasher, to ensure they are only using the electricity being generated, not paying for extra from the grid.

If they really want to maximise savings, occupiers can check the PV inverter to see how much electricity the solar roof tiles are generating and keep a list of the power rating of their appliances, so they can make informed decisions. If the PV inverter is installed in the loft, then fitting a solar energy monitor in a convenient location is a good idea. Some can even be linked to a computer or smartphone, so users can easily see how much power they are generating. If they have a smart meter, they can then compare this with how much electricity they are using at any given time.

Solar roof tile specification support and more from Marley

The Marley SolarTile® is designed to help you achieve the best savings from your solar roof tiles. As well as the easy-to-install PV panels, which are part of our complete roof system, we also offer electric vehicle (EV) charging points and electrical safety products.

We are constantly researching and innovating, coming up with new products to enhance our system, and we can assist with technical inquiries, specification support, installer training and SAP calculations. Contact us today to find out more, or download our Marley SolarTile® brochure.