KEY POINTS TO CONSIDER
Installing solar photovoltaics (PV) together with (EESS) battery storage can offer long-term savings, better self-sufficiency, and lower environmental impact. But it’s not just “buy panels, stick them on the roof and done.”
There are many technical, financial, regulatory, and practical factors to get right to make sure it’s a good investment.
PLUS, choosing the right people to advise, instal, deliver, and explain what to expect and what has been installed.
Here’s a quick summary of the 10 key points which we’ll expand upon, below:
- What are your goals & usage pattern?
- Roof/site suitability for solar modules (panels).
- Size of the solar array + battery.
- Types of battery & system configuration (EESS).
- Safety, regulations and certifications.
- Cost, savings & payback.
- Positioning, installation & logistics.
- Monitoring, usage behaviour & future-proofing.
- Limitations and potential downsides.
- Advice. Have you chosen the right installation partner?
Now, let’s develop some of the details:
1. What are your goals & usage pattern
Before anything else, clarify why you want solar + storage, and how you use electricity in your home. Knowing your annual electricity consumption (in kWh), how it’s distributed over time, and future projections will help design the system you will need to instal.
- Do you want to cut electricity bills, especially in peak hours?
- Do you want emergency backup power during grid outages?
- Are you anticipating higher electricity demand (EV charging, heat pumps, etc.)?
- When in the day (or year) do you use most of your electricity? If you use a lot during the daytime, more of your solar is used directly; if mostly in evenings, storage is essential to maintain supply day and night.
2. Roof/site suitability for solar modules (panels)
Some of the key physical and environmental conditions:
- Orientation & tilt: South-facing roofs are ideal; east/west can work, north less so. Tilt angle matters to maximise solar exposure.
- Shading: Chimneys, trees, neighbouring buildings shading during parts of day, reduce output. These are checked and modelled in planning.
- Roof condition & structure: Is the roof sound? Is its lifetime shorter than that of the system to be installed? Will it need repair or reinforcement? Panels add weight, which is too often ignored during planning.
- Space: Enough area for desired module (panel) capacity.
- Planning constraints: If in a conservation area, listed building, or if the roof is visible from protected vistas, there may be restrictions. Often permitted development rights cover solar, but we will need to check with the local authority.
3. Size of the solar array + battery
Sizing has a big impact on cost, savings, and performance:
- How big should the PV system be (peak output in kW)? This depends on roof size, budget, and usage.
- How big an EESS battery storage (capacity in kWh)? We’re looking for the optimum storage to balance continued energy usage, day and night. If you are not using what you generate, the EESS enables sell-back to the National Grid. For many homes, batteries of 5-15 kWh are common.
- Matching modules & battery: If you’re adding storage later, or expanding in the future, consider modular / scalable systems. Your expert installer will advise.
4. Types of battery & system configuration
Different technologies and designs come with trade-offs:
- Battery chemistry: Lithium-ion is most common today (good energy density, lifespan, cost), but there are alternatives. Consider cycle life, warranty, degradation.
- Most home systems in the UK range between 5kWh and 15kWh. You can choose between: AC-coupled systems, which are easier to add to existing solar panel systems. DC-coupled systems, which can be more efficient, but are usually installed alongside new solar concurrently.
- Backup load / off-grid ability: If you want backup in blackouts, ensure the system supports a backup circuit or load switching.
5. Safety, regulations and certifications
- Installers should be MCS-certified on systems <50kWp (Microgeneration Certification Scheme) so standards are met, and warranties/insurance are valid.
- Fire safety: New UK standard PAS 63100:2024 sets guidance for installation locations (where batteries can / cannot be installed), mounting, enclosure, ventilation etc. Avoid bedrooms, tight cupboards, lofts (for new installs). Use fire-rated surfaces. This should be confirmed with the insurance provider and Fire Safety Officer. Again, all of this will be explained fully by your adviser / installer
- Electrical safety & local network notifications: Notify the Distribution Network Operator (DNO), get relevant electrical certification (EIC or similar). Ensure wiring is according to UK regulations (BS 7671 etc.).
6. Cost, savings & payback
Key financials to consider:
- Upfront cost: Panels, batteries, inverters, installation, electrical work, possibly roof work. Battery cost can range (before installation) from a few thousand to over £10,000 depending on size & brand.
- Ongoing costs: Maintenance, possible replacement (battery lifespan), inverter failures etc. Note: Fitting the right / best components in the first place saves considerable in the long run.
- Incentives & tax:
- VAT relief: solar panels + battery installations are zero-rated VAT (0%), (at present, domestically in most cases).
- Smart Export Guarantee (SEG): You can be paid for surplus electricity you ‘export’ (sell) back to the grid. But rates are relatively low, so optimally you use more yourself.
- Grants / schemes (can be regional): e.g. interest-free or low-interest loans (Scotland etc.), local authority schemes.
- Payback period: Depends strongly on how much electricity you use when modules generate, how much you export vs store, electricity tariffs, battery costs & lifespan. Detailed modelling will help guide your decision making.
7. Positioning, installation & logistics
- Where to locate the battery: utility room, garage, external enclosure are common. Ventilation, accessibility, safety (fire & proximity to other structures) matter. [Loft installations are now generally discouraged for new installs under safety standards.]
- Inverter: capacity and compatibility with panels and battery. If upgrading or retrofitting, check that your existing inverter can support battery, or whether a hybrid or new inverter is needed.
- Cabling, wiring, protection, surge protection etc.
- Installer credibility: Ask for detailed quotes, breakdown of cost, warranties (battery, inverter, workmanship), and after-sales support. Check reviews, previous installations.
8. Monitoring, usage behaviour & future-proofing
- Monitoring system: Many battery systems come with apps or online dashboards so you can see when generation, storage, usage, export etc are happening. This helps you to optimise usage and value.
- Behaviour changes: Even with solar + battery, tweaks such as using appliances during daylight hours, shifting loads, choosing time-of-use tariffs can make a big difference.
- Future demand: If you plan to add EV charging, heat pumps, or growing household usage, build in capacity (battery size, inverter rating, roof space) to accommodate growth.
9. Limitations and potential downsides
It’s not all positives; be realistic about drawbacks:
- High upfront outlay. Payback can take many years, especially if usage patterns don’t align.
- Less generation in winter, or low sunlight days. So, your EESS may not cover evenings fully in winter.
- Batteries degrade over time; warranty conditions may limit useful lifespan. Replacement costs may come in before you move or before full payback.
- Export tariffs (SEG) are relatively low, meaning you often get more benefit from storing and using your own power than relying on producing and exporting.
10. Advice
Unless you are an expert yourself, you will be reliant on the advice you’re given by your consultant / installer. Be sure you have chosen the right one.
- Does the relationship feel right?
- Are they a “yeh, no problem mate” or “let’s sit down and properly understand what you think you need, and why. There are many alternatives, let’s get it right for you, from the start.”?
- Do they have the right qualifications and evidential history (see 5, above)?
- Are they showing you a full, illustrated installation plan, illustrated, with all components detailed within an itemised quotation, and payback forecast, all fully detailed?
- Are they explaining the downsides as well as the ups?
- Are they suggesting a sensible, affordable maintenance plan?
