How Many Solar panels for a Washing Machine

With solar systems becoming more affordable and ever more efficient home appliances available on the market, more households are considering using solar power as an alternative or backup power solution or connecting more appliances such as washing machines to the existing solar systems.

If you have an existing solar system and are wondering if you can connect a washing machine to it, or wondering if it is worthwhile connecting your washing machine to a solar system then this post is for you.

Read on to learn if you can run a washing machine on solar, whether it is worth it, how many panels you need, and what type of system you should use plus alternatives to using solar power for the washing machine.

Can You Run a Washing Machine on Solar?

Yes, you can run a washing machine using a solar system, either an off-grid solar system ( consisting of solar panels, batteries, charge controllers, and inverter) or a grid-tie solar system ( just solar panels and grid-tie inverter).

The system (capacities) should be sized to handle the surge power rating of the washer and supply the energy needed for the length of the cycle.

The washer draws more power at the start, when heating water or when spinning. If these are accounted for during the sizing of the system then you should be able to use a solar system.

How Many Solar Panels you Need?

The number of solar panels that are required to run a washing machine depends on several variables:

  • how many hours of sunshine your location receives on average per day,
  • the washer’s power consumption and
  • whether you are sizing the system for just the washing machine or other appliances,
  • rating of the solar panel (watts) used.

Let’s assume you are sizing for the washing alone without any additional appliances to keep it simple.

If the washer has the following specifications on its nameplate, voltage -115V, current – 9 amps.

Assuming the longest wash cycle is 2 hours long and the installation, location receives 4 hours of sunshine, then the number of solar panels for both the off-grid and grid-tie solar systems is as follows:

Offgrid Solar system

You’ll need about 600- 800 watts of solar for this washing machine to supply enough power for that one washing cycle.

If you are using 200 watt solar panels, then you’ll need 4 x 200 watt solar panels.

Battery bank

You’ll need at least a 12V, 400 Ah AGM or 24V, 200Ah AGM battery bank. This assumes one wash cycle.

You’d probably want to have some buffer to counter cloudy weather and other factors you could go for a slightly more capacity than the specifications above.

An example of a solar system you can use :

A 1.2 kW solar system, with 2 x 200 Ah AGM/GEL batteries connected in series for a 24V system with a 3,500 Watt, 24V pure sine wave inverter, and a 60A MPPT charge controller.

You may be interested in this post: Should you invest in a 1 kW Solar system (what appliances can you run?)

Note: This is just one off-grid solar system that you can use. There are other configurations that you can use to power your washer.

Grid-tie system

For a grid-tie system, you can go for at least a 1-2kW of solar panels and a 1-2kW grid-tie inverter.

How Much it Costs?

Costs of solar systems vary depending on the size and manufacturer. A 1.2 kW solar system complete with 60A charge controller, 2 x 200 Ah AGM batteries, and 3,500 watt inverter costs an estimated USD 3,000 at current market prices.

Is it Worth it?

If your objective is to save money, then investing in a 1.2kW off-grid solar system is not worth it from a financial savings standpoint unless subsidies are provided.

The payback period for such as system can be as long as 85+ years!

This assumes:

3 washes per week, with each wash lasting about 2 hours.

Daily energy draw

The estimated daily energy draw is 115V x 9 amps x 2 hours = 2,070 watt-hours.

Weekly energy draw

Daily energy consumption of 2,070 watt-hours x 3 washes each week = 6,210 Wh or 6.2kWh.

Monthly energy consumption

weekly monthly consumption x 4 weeks = 6.2 kWh x4 = 24.8 kWh.

Annual electricity consumption

monthly electricity consumption x 12 months = 24.8 kWh x 12=298.1 kWh

The estimated annual electricity consumption works out to be about USD 35. This is from the electricity tariff of 12 cents per kW x 298kW.

If the solar system cost USD 3,500 then the payback period is USD 3,000 /35 =85 years!!

How to Reduce a Washing machine’s Energy Consumption when Using Solar

You can reduce the washing machine’s energy draw and size of the solar system by following the tips below:

#1. Use the washing machine during the day when the sun is out to reduce the energy draw on the batteries (for an off-grid solar system).

#2. Use the washer in eco-mode as it requires less energy to run the washer. Specifically, setting the washing machine to use cold water only can result in a significant reduction in the power drawn by the washer.

Some manufacturers note a 75% power reduction when water heating is turned off.

Do this First: Tips for Connecting a Washing machine to an Existing solar system safely

If you have an existing solar system and are wondering if you can connect a washing machine to it safely, it is best that you consult a qualified solar system installer to inspect and confirm if there is enough solar power, inverter, and battery power capacity to power the washer.

The installer can advise if any upgrades to the solar system are required.

Alternatives to Using Solar to Run a Washing machine

Besides solar, you can use a generator to power the washing machine. The generator rating depends on the washing machine capacity.

Keep in mind that the generator requires gas and regular maintenance to work reliably.

Final Word

Yes, you can run a washing machine on a solar system. The number of solar panels to you need depends on several factors, the power consumption of the washing machine, the number of sunshine hours your location receives and the power rating of the solar panel used.

Keep in mind that running a washing machine on an offgrid solar system has a long payback and is not worth it from a financial perspective if you’re using an off-grid solar system.

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