By Christopher Soper

It’s expected that social landlords will be required to ensure all their homes reach EPC C by 2030. Reaching this target will be challenging for many, as whilst most social homes already reach EPC C, there are many more in EPC D.

The housing sector has had a ‘fabric first’ mantra for decades, based on delivering high-level thermal insulation improvements. Nigel Banks argues that what’s needed is a ‘fabric fifth’ approach – where decarbonisation involves prioritising the installation of heat pumps and smart technology, and measuring solar photovoltaic (PV) before insulation (in part due to the affordability of the measures).

Electrification of heating would be unlikely to assist with getting to EPC C (unless the EPC formulas change significantly before 2030. PV, however, can and has been used in social housing to improve EPC ratings, including to above C, so is now the time to prioritise PV in social housing?

A previous review of the impact of CESP/CERT schemes in social housing, which included various measures such as external wall insulation, new boilers and solar, found that many residents didn’t see any significant savings in energy use, with most instead seeing improved thermal comfort, having either increased the set temperature or length of time that the heating is on within the home. Where savings were reported, these were greatest where either gas heating boilers or Solar PV were installed, not insulation alone.

Humans have harnessed the sun’s energy for thousands of years – for example, with south facing windows. The electrical photovoltaic effect was defined in 1839 but it wasn’t until the 1970s that solar PV was successfully commercialised. Since then, the efficiency of panels has dramatically improved, and the price has fallen. Between 2010 and 2019, many solar PV systems were installed with the benefit of feed-in tariffs, paying a guaranteed amount per kWh generated, including many on social housing. Since then, most solar PV in social housing has been on new builds, with limited installs on retrofit projects. (See ONS data here.)

The benefits of a PV-first strategy for tenants and landlords

1. Compared to other possible improvements there’s a low investment cost per SAP point gained, with historically low PV prices currently due to high levels of production in China.
2. Low resident disruption, with most of the work taking place outside, with limited requirements to disturb residents’ homes and belongings.
3. Planning permission isn’t generally required for PV. There are exceptions (for example, for listed buildings) but it’s easier to undertake than external wall insulation, which may require planning.
4. Residents don’t need to change any behaviours to see some savings, and may be able to increase savings if they change the times that they use their electricity to make the most of the PV.
5. In this era of high energy prices, it’s almost guaranteed to reduce bills for residents.
6. Landlords can gain a valuable income generation stream for any electricity that’s generated and is exported, due to not being used in the home.
7. Solar PV is suitable for most houses and many flats. Due to the relative costs and efficiency gains, it’s no longer true that you need a south-facing roof – in fact, the best arguable orientation is to have half facing east and half west, to maximise morning and evening generation.
8. Installing PV arguably prepares for the electrification of heating in the future.

 What are the risks of PV-first strategy?

There have been a few negative press stories about previous PV projects in social housing. Notably, a project ran into difficulties in Stoke-on-Trent, where as part of the install the tenant was locked to a specific supplier for their electricity.

Similarly, ‘rent a roof’ schemes have been set up in the past where the landlord doesn’t pay for the solar panels but benefits from the increase in the SAP points. The residents pay for the electricity generated (usually at a discounted rate) and the PV provider gets paid via this and any export. This is clearly a very cost effective way to get to EPC C, but it doesn’t provide the resident with all the benefits of PV.

Tenants may not fully understand the PV system. They may believe they’re getting free electricity and, for example, put the tumble dryer on or get pet snakes etc, and use more additional electricity than they actually generate. Ensuring residents are able to monitor their generation and usage may help. However, there’s a risk residents will be confused and not see the benefit of the PV.

Where a very large PV system is installed, especially if it’s for a household that’s out during the day, it’s likely that electricity will be exported and therefore residents won’t see the benefits. Whilst the use of a solar diverter to heat hot water or batteries could be used to store the generated energy, these are additional costs to the landlord and need to be factored in. Without these, there’s a likelihood that a signification proportion of the electricity will be exported, and the resident won’t get the benefit.

Installing PV on old roofs has been known to cause leaks. This can be due to damage caused during installation or because the roof is approaching the end of its lifecycle and disturbing it to install the panels weakens it further. I’m aware of one install in an exposed location where it was found that the wind on the solar panels was causing roofing tiles to lift and crack, requiring a new roof shortly after the PV was installed.

Repairing a roof with PV on it, even where the repair is distant from the PV and unrelated, may require an electrician to isolate the panels to enable safe access to undertake the standard roof repair. This is likely to significantly increase future repair costs for roofs. Therefore, if the existing roof covering is more than 45 years old, it would be wise to carefully consider replacement at the same time as PV, as PV has an expected lifecycle of 25 years, and the roof could be expected to need renewal before the PV reaches the end of its life.

Historic PV installs have often been found to be turned off. This can be caused by an electrical trip switch or because it’s been isolated to enable work such as an EICR and not then switched back on. Remote meter readings can help, with this enabling you to contact the resident and make sure they’ve switched it back on or dispatching an engineer to turn it back on. However, this does result in additional administration for the landlord. If you don’t do this, then residents and landlords may not gain the benefits of the system.

If you install PV on a roof, identify if you need to insulate the roof to get to EPC C. Insulating it may be more difficult from the inside. This is especially the case on flat roofs and room in roof constructions. Consideration should be given to checking and documenting insulation prior to installing PV.

PV has been predominantly thought not to be suitable for flats, due to such roofs being shared and EPCs don’t usually recommend PV on flats. However, flats have been successfully upgraded with PV. Two main options have been deployed. On smaller blocks, individual systems for each flat are possible in just the same way they are for houses. For larger blocks, a solar share system can be deployed. This can share the electricity from a larger system between each of the flats. However, on some new builds it’s been known for the PV system to only be connected to the communal supply. This results in very little benefit to the residents, as the generation often far exceeds the demand within the common area.

With PV large scale deployment being a relatively recent measure, the regulations around the technology are still evolving. For example, the location where inverters are installed has varied over time, and it’s now recommended by many that these are located externally to the property. As these regulatory changes are not retrospective it may not be necessary to return to earlier installs and amend these. However, it may be that if repairs are needed then action may be potentially required. It’s also been suggested that insurance companies may make specific requests.

Fire safety is an important consideration when installing PV. There were a number of PV installs on the vertical elevations of high-rise buildings. These would no longer meet the building regulations for non-combustible walls. There have been fires due to PV and there are products which can reduce this risk. However, as usual, good design is key, in particular when ensuring that where there are vertical fire break barriers in a roof, the PV panels don’t span this area to ensure that fire breaks are in place. This may reduce the quantity of PV that it’s possible to install on some homes.

The efficiency gains of new solar panels in recent years might be expected to continue. Investing now locks you into the current technology and if it improves later, it’s hard to swap. You therefore may miss future opportunities to install better PV systems!

PV has a 25-year life cycle. Therefore, most systems that have been installed are still within their life cycle and few are yet to enter the waste streams. As a result of this, the facilities for the recycling of PV aren’t yet developed. In theory this should be possible in the future, and it’s likely that once more waste is generated this will be developed, so it shouldn’t at this time be a barrier to adoption.

 Conclusion

There’s a good case to be made that landlords would be wise to prioritise PV in their plans to achieve EPC C, where this is possible on a house, over hard and disruptive to install insulation upgrades. It’s possible, if this option is taken as the first and main measure, that the cost to reach EPC C for landlords for hard-to-treat homes might be reduced to affordable levels, enabling more residents to benefit overall, and it may reduce the need to dispose of valuable hard-to-treat social homes.