How Long Does Solar Panel Installation Take?
Fitting the panels is the quick part. Most of the wait is the design and paperwork before install day, and how long that takes depends mainly on the size of your inverter. Here's what we've seen across 1,252 Spark installs in 2025 and 2026.
On this page
- The median time from signing with Spark to install day was 19 days. Half of homes were fitted within 13 to 30 days.
- Systems with a 3.68 kW inverter were quickest, at a median of 17 days. Larger inverters need network operator approval, so they took longer.
- About one order in five needed an extra half day on site for a larger or more complex roof.
How Long It Takes, by Inverter Size
The size of your inverter makes the biggest difference to the wait.
| Inverter | Homes | Median, signing to install | Middle half |
|---|---|---|---|
| 3.68 kW | 821 | 17 days | 13–24 days |
| 5 kW | 189 | 26 days | 20–37 days |
| 6 kW | 217 | 35 days | 24–53 days |
| 8 kW and over | 25 | 45 days | 25–56 days |
The gap is mostly network operator approval. For 6 kW systems the operator took a median of 12 days to approve the connection, and 21 days for 8 kW and over. Our sizing guide explains how the inverter is chosen.
Step by Step, From Quote to Switch-On
Here's what happens between your first quote and the day your system is switched on.
- Quote and survey. We look at your roof, your bill and how you use electricity, then design the system and give you an independently validated savings forecast.
- You sign. Your quote confirms the system, the price and any finance.
- Design and paperwork. We finalise the design and deal with the network operator. For larger inverters, this is where most of the waiting happens.
- Scaffolding. It usually goes up shortly before install day.
- Install day. Our team fits the panels, battery and inverter, connects everything and checks it's working.
- Handover. We show you the EcoFlow app, take the scaffolding down and send your handover pack.
- Certificates and care call. You get your MCS certificate, which you'll need to apply for an export tariff, and we call to check everything is running as it should.
What Can Slow It Down
Most installs follow the timings above. These are the usual reasons one takes longer.
- A larger inverter. Anything above 3.68 kW needs the network operator's approval first.
- No electricity bill to hand. We can estimate, but a bill makes the design quicker and more accurate.
- A complex roof. More roof faces, shading or difficult access can mean an extra half day on site.
- Busy periods. Waits vary through the year. For homes fitted in 2026, the median was 24 days.
How We Worked Out These Figures
These figures come from SparkOS, our own operations system.
They cover 1,252 Spark installs completed in 2025 and 2026, measured from the date the customer first signed to the install date. "Middle half" is the range between the 25th and 75th percentile. We update these figures every quarter.
Your Questions, Answered.
How long does it take to install solar panels?
From signing to install day, the median across 1,252 Spark homes was 19 days. Systems with a 3.68 kW inverter were quickest, at a median of 17 days.
How much time does a battery add?
Very little, as the battery is fitted at the same time as the panels. The bigger factor is the inverter size, which decides whether the network operator has to approve the system first.
What is a G99 application?
It is the network operator's approval for systems with an inverter larger than 3.68 kW. We handle it for you. For 6 kW systems it took a median of 12 days.
When do I start saving?
From the day your system is switched on.
Get Your Install Date
A free, no-obligation quote with EPVS-validated savings and a realistic timeline for your home.
Get My Free Quote