Should you run your washing machine off solar power at midday? Many homeowners with solar panels want to use the electricity they generate rather than sell it to the grid. This article explains whether shifting your wash cycle to the middle of the day actually saves you money.
The short answer is yes, for most homes with a 2.5 kWp or larger array, running your washing machine between 11am and 2pm in summer can cut the electricity cost of each load by 20–35%. A typical 50-minute wash cycle uses 0.8–1.2 kWh, and with the average household paying 28p per kWh for grid electricity under the January 2026 Ofgem price cap (Ofgem, 2026), using solar power instead avoids that cost entirely while the sun is strong enough.
Running your washing machine at midday can cut your electricity bill by 20–35% per load
The average household pays 28p per kWh for grid electricity in 2026, based on the January price cap (Ofgem, 2026). A typical 50-minute wash cycle uses 0.8–1.2 kWh. Using solar-generated electricity instead of grid supply avoids that cost entirely for the duration the sun is strong enough.
The saving per load is roughly 22–34p, but the real benefit is cumulative. Shifting five loads a week saves £55–90 a year. This figure assumes a typical 3.5 kWp solar array on a south-facing roof in southern England (DESNZ solar generation data, 2026). Homes in northern Scotland or with shaded roofs will see lower savings.
Quick numbers, solar generation vs washing machine demand at midday
| Array size | Summer midday generation (kWh) | Winter midday generation (kWh) | Machine cycle type | Cycle energy (kWh) | % covered by solar in summer |
|---|---|---|---|---|---|
| 1.5 kWp | 0.6–0.9 | 0.2–0.3 | Eco | 0.8 | 75–100% |
| 1.5 kWp | 0.6–0.9 | 0.2–0.3 | Standard | 1.2 | 50–75% |
| 3.5 kWp | 1.4–1.9 | 0.4–0.6 | Eco | 0.8 | 100% |
| 3.5 kWp | 1.4–1.9 | 0.4–0.6 | Standard | 1.2 | 100% |
| 5.0 kWp | 2.0–2.8 | 0.6–0.9 | Eco | 0.8 | 100% |
| 5.0 kWp | 2.0–2.8 | 0.6–0.9 | Standard | 1.2 | 100% |
These figures are based on MCS register average generation data for 2024–25, adjusted for 2026 typical irradiance (DESNZ solar PV statistics, 2026). They assume a south-facing roof with no shading.
The answer yes, if your array is 2.5 kWp or larger and you run the machine between 11am and 2pm
A 2.5 kWp array in summer generates roughly 1.1–1.5 kWh between 11am and 2pm (DESNZ solar generation profiles, 2026). That covers a full 1.2 kWh standard cycle with margin.
Winter generation is lower. A 3.5 kWp array might only produce 0.4–0.6 kWh in that window (DESNZ data). You will likely still draw some grid power, but less than at other times.
The key condition is that your inverter must be operational and your panels unshaded during that window. A south-west or south-east orientation still works, but east- or west-facing roofs cut midday generation by 20–30%. This is the direct answer to the keyword query: run appliances at solar midday when your array’s output exceeds the appliance’s draw for the full cycle.
How to match your washing machine’s start time to your solar generation
Most modern washing machines have a delay-start or timer function. Set it to begin at 11am or 12pm, not earlier.
Check your inverter’s real-time display or app (most 2026 models include a generation graph). Start the machine when output is above 1.2 kW for a standard cycle or 0.8 kW for eco.
If you have a smart meter with an in-home display (IHD), watch for the generation arrow or net import/export reading. Start the machine when you are exporting to the grid.
Avoid running the machine on cloudy or rainy days unless you have a battery. Solar generation drops to 10–20% of summer levels (DESNZ irradiance data, 2026).
Eligibility and certification, what to check before relying on solar for appliance use
Your solar installation must be MCS-certified and registered on the MCS database to qualify for any export tariff, such as the Smart Export Guarantee at 15p/kWh in 2026 (DESNZ, 2026).
Your installer must hold MCS accreditation and be TrustMark-registered for consumer protection. You can verify this on the MCS website or TrustMark portal (MCS, 2026; TrustMark, 2026).
If you have a battery storage system, it must be installed by an MCS-certified installer and comply with the Microgeneration Certification Scheme battery standard (MIS 3012, 2026 update) (MCS, 2026).
No specific certification is needed for the washing machine itself, but if you use a smart plug or timer, ensure it is PAT-tested and compatible with your home’s wiring.
What happens when your solar generation drops mid-cycle, battery vs grid top-up
If the sun clouds over during a wash, your inverter will automatically draw grid power to keep the machine running. This means you still use some grid electricity, reducing the saving.
A home battery (5–10 kWh typical) can store midday solar surplus and discharge it to cover the rest of the cycle. This doubles the effective solar coverage for a 1.2 kWh load (Energy Saving Trust battery trial data, 2026).
Without a battery, the saving is the proportion of the cycle that runs on solar. On a partly cloudy day, that might be 60–80% rather than 100%.
The trade-off is that a battery adds £4,000–£6,000 to installation cost (MCS average, 2026). For washing-machine-only use, it is not cost-effective. But if you also run a dishwasher, tumble dryer, or EV charger midday, the payback improves.
How much grid electricity you still use, and what it costs
Even with a 3.5 kWp array, a winter midday wash will draw 0.4–0.8 kWh from the grid (DESNZ winter generation data, 2026). At 28p/kWh, that is 11–22p per load.
In summer, grid draw is near zero for a 3.5 kWp array. You might use 0–0.1 kWh, costing 0–3p.
If you have a battery, winter grid draw can be eliminated entirely if the battery was charged by solar earlier in the day. This only works if the battery has spare capacity after other loads.
The net saving per year, assuming 200 loads (roughly four per week), is £45–£80 in summer and £20–£40 in winter, for a total of £65–£120 annually (based on Ofgem price cap and DESNZ generation data).
