In the first of a series of blog posts regarding technologies for retrofitting homes to be more sustainable, PJH are looking at solar panels. Beginning with an introduction to solar panel retrofit and along with facts, pros and cons, costs for an average home, potential payback timeframes and the required space for a Solar PV system.
Solar Panel Retrofit
Three out of five (60%) homeowners don’t believe that the energy use of their home has much impact on carbon emissions, according to research by the National Housing Federation (2021). Along with figures that more than one in four (28%) homeowners have no plans to make “eco-upgrades” within the next ten years.
It’s not always achievable to address all the sustainability issues of a dwelling in one go. Creating a retrofit plan for renovations and upgrades towards an end goal will help reach the desired level of integrating ‘green’ energy saving technologies like solar panel retrofit into your home.
There are two types of solar energy systems that can benefit a home; solar photovoltaic (PV) and solar thermal. Solar PV are designed to convert the energy from the sun into electricity to be used around the home, while solar thermal converts the energy into heat for household water.
Different types of solar panel systems are available to suit different requirements. They can be retrofitted into existing roofs creating minimal disruption or they can be integrated as part of a new roof system with options for flush finishes to create a sleek look. Solar tiles are slowly becoming more widely available also.
According to the Eco Experts (2023) the costs of installing solar panels has dropped by around 88% since 2010 meaning combined with the increased costs of electricity, undergoing a solar panel retrofit can save around £522 per year on average.
There are various savings based on different occupants’ usage. Utilising batteries to store excess power that the solar panels generate provides the option for power to be sold back to the network.
The two most common types of solar PV panels are Monocrystalline and Polycrystalline. The Monocrystalline panels are more efficient but more expensive, they are dark with a smooth appearance and have a higher efficiency rating compared to Polycrystalline panels, as the cells are made of a single unbroken silicon crystal. The higher output vs surface area makes them better suited to dwellings with smaller roofs like an average sized 3-bedroom dwelling. The Polycrystalline panels have cells that are made up of many smaller silicon crystals giving them the speckled, typically blue appearance. The lower efficiency and lower costs make these generally more cost effective for larger roof areas.
While a south facing roof is best, PV panels don’t require direct sunlight therefore east and west facing roofs can also benefit.
Pros and Cons of Solar Panel Retrofit
Costs – For an Average 3 Bed Semi-Detached House
There are different types of solar panels for different requirements and budgets when under going a solar panel retrofit. Typical solar panel systems for a 3-bedroom semi-detached home can cost on average £5,500. According to the Eco Experts (2023) they can reduce annual energy bills by £522. The government has also removed VAT so that purchases of solar panels made in the next 5 years can benefit from 0% VAT.
PJH Architectural Services are in the process of creating relationships with solar panel specialists who will be able to further assist in assessing the suitability of a dwelling and any proposed solar panel retrofit works.
Payback Timeframe for a Solar Panel Retrofit System
Homeowners can achieve a varying amount of savings from utilising solar panels alone or as part of a larger retrofit project. For the example if the average cost of fitting a solar panel system is £5,500, with annual savings on average at £522 (according to the annual savings graph based on October 2022 fuel prices) then that’s a 10-year return on investment. Depending on whether you sell back to the grid or not, this could be reduced further by the money earnt from the excess power generated.
Required Space for a Solar Panel Retrofit System
Solar panel systems have different requirements for space, whether it’s the physical space occupied by the solar panels or the associated ‘behind the scenes’ tech. The two most common inverters come in two different setups, string inverters or micro inverters. The first and most common is the string inverter, it requires a single inverter that links all the solar panels together so that they form one larger solar panel being funnelled into the one inverter. Although this is the most common type for a solar panel retrofit as they are the cheapest, if the dwelling in question is prone to shading as the panels only output as much as the lowest performing panel generates. The second option, micro-inverters are more expensive but are more efficient as each solar panel operate individually meaning underperforming panels can be adjusted or swapped out accordingly.
The lifespan of micro-inverters outperforms string inverters due to them only having to process the direct current (DC) from a single panel, whereas string inverters are required to convert the full load from all linked solar panels which can put a strain on it. It’s likely that a string inverter will require replacing at least once during the lifespan of the solar array, however micro-inverters often come with a 25-year warranty and more often than not last just as long as the panels.
Conclusion
In conclusion, there are two main solar panel retrofit systems that can benefit a dwelling, with the most popular solar PV option available for different budgets and to suit different needs/usage. The technology is ever evolving and improving, more dwellings are able to benefit from solar PV as south facing roofs are not the only orientation that can be utilised. There are increased savings available to be made due to the higher energy bills which will shorten the payback timeframe with the option to also sell excess electricity back to the grid. Solar panel systems can be retrofitted to existing roofs with minimal disruption or integrated as part of a larger project involving a reroof for a sleek finish.
Ask us for advice
If you have a project in its infancy and want to have an informal chat regarding your options, feel free to contact us, we are always happy to provide friendly and knowledgeable advice. Get in touch on 0161 460 0382 or email the team at enquiry@pjhas.co.uk
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