Do I need an efficient solar panel?

What the Guru says

Hi Solar Guru, the solar salesperson recommended a particular panel because that one is very efficient But it’s also more expensive. Is efficiency really that important?

This is a really good question, because if you think about the future, you are probably electrifying your life more and more over time.

More efficient panels will allow you to get more generation off your roof, especially when you think about electric vehicles, heat pumps and electrifying everything which is inevitable coming into the future.

So yes , a higher efficiency panel is a great way to go, just get the balance right between your budget and efficiency and fill the whole roof with PV panels.

Efficiency and solar panels – is it important?

Not all solar panels are built equal. Some are bigger and smaller, some have thicker frames, and some use different technology. All these variants can also mean the output and efficiency per panel model can change.

Usually, the more efficient a solar panel is, the more electricity it produces per m2. So if one can fit a 10 kW system on a roof with a standard panel, and we now swap over to a highly efficient panel with a 10% higher output (e.g. a 400W panel changes to a 440W panel of the same size), then we would be able to get an 11 kW system on the same roof space.

Also, the more efficient a solar panel, the more it will cost, and a 10% more efficient solar panel will usually cost quite a bit more than just 10%. So is it worth it?

With the growth of EV vehicles, the demand for larger and large home solar systems will increase if residents want to charge them from their solar. Unfortunately, architects in the past made little reference to solar; therefore, many roofs have gables and valleys for stylistic and aesthetic reasons, making it harder for panels to be installed and to gain a large PV system.

So, in summary, the importance of efficiency in solar panels depends on your specific goals, budget, and future needs. The key factors to weigh up are;

How big is my roof space? 

A higher efficiency panel may not be needed if your roof is huge. If, on the other hand, you live in a townhouse, you might have to go for the most efficient panel to get the largest possible system.

What are my future energy needs?

Imagine your workplace has just declared that an EV vehicle will be provided to you as part of your salary package. How handy would it be to have an EV charger at home, powered by a solar system. so if your energy demand suddenly increases, choosing a more efficient PV panel can help you generate more electricity and negate a larger part of your electricity bill. If you want to read a guide about charging your Electric Vehicle with Solar, refer to the Solar Analytics guide here:

Family on couch surrounding phone
A growing family will need more electricity in the future

Better long-term ROI

A more efficient panel can, as long as it is not heaps more expensive, give you a better ROI than a standard panel because you can install a bigger PV system for the same labour cost. A bigger PV system means more electricity output and larger savings.

Smaller carbon footprint and faster-embedded energy payback

A more efficient panel usually uses the same tempered glass and aluminium frame as a less efficient model. This means a very similar energy input; one can get a PV panel that produces more renewable energy over its working life. Therefore the carbon footprint of a more efficient panel is smaller, and the output of renewable energy is larger than that of a standard module.

More rebate

The current Federal Government solar power rebate is linked to the size of a solar system. If you can only fit 20 panels on your roof, a 440W panel versus a 390W panel will give you a 1 kW larger system and, therefore, a larger rebate. While the more efficient panel will also cost more, the rebate will often cover some of this additional expenditure.

Solar Panels on roof
How much shade will my roof get in the future from nearby trees?

How much sun does my roof get?

Higher efficient panels often also generate more power in lower light conditions. Therefore, if you have a partly shaded roof or lower sun irradiation, e.g. in Hobart (low)  vs Darwin (high),  you might be better off choosing a higher efficient panel.

So you can see higher efficient panels can offer advantages. Still, you must always weigh your financial situation, solar power needs, available roof space, how long you plan to stay home, and the available module product.

Finally, you need to consider your energy needs. If you have a large home or use a lot of electricity, you may need to choose more efficient panels. However, you may get away with less efficient panels if you have a small home or use a relatively small amount of electricity.

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