Solar panels facing North, East, West and which is best?
I thought some real data rather than just talk may be a useful guide for people thinking about their options.
Some preliminaries;
A good, ethical installer and designer are really your best friend in your decision making. They are out there but get recommendations from friends or go to somewhere like SolarQuotes.com.au as this is by far the biggest source of referrals and feedback in Australia.
These notes are general and based on Melbourne so it will be slightly different for your location.
Traditionally when solar panels were very expensive, people wanted to get maximum bang for their buck and usually could only afford 2-3kW. Facing them due north achieved this goal.
Now solar panels are cheap and given you will no doubt will want and EV sooner rather than later (a big battery you can use for blackout protection – another discussion), you should put the biggest sized solar system you can fit or afford. Solar hot water used to be a cost effective solution, but now the panels just take up space you could use for PV so don’t install solar hot water anymore (sorry to the SHW installers but it doesn’t stack up anymore). Use a heat pump hot water system run it as much as possible during the day as it then acts like a storage battery absorbing excess solar electricity. Same with your heating and cooling – have them on timers so you maintain your house at a comfortable temperature during the day and then in the evening you need less energy to maintain the temperature – but you all knew that anyway.
So N, E, W or other?
I have put some images in this post so you have the numbers in more detail.
However, in summary, facing north will still give you the most energy overall. BUT because most of this is right in the middle of the day you may only use 30-55% of the energy and export the rest and with FiT going down this becomes almost worthless. Time to get an EV.
East facing gives you more morning energy especially in summer, but less in the afternoon and West is the opposite. If you have a hot westerly facing home needing lots of summer AC go west young man/woman/prefer not to say.
If you want to maximise self-consumption and not waste your energy by giving it to greedy energy retailers, the best compromise is a mix of East and West facing panels. In winter you will self consume 78% of the generation compared to just 55% for North facing panels. Most solar inverters can manage 2 different directions without a problem, but if you also put some facing a third direction you will need additional equipment which increase the cost per kW significantly, so stick to 2 directions where possible.
What about South you ask. Well for our FNQ and Darwin cousins, they can face them anyway they like and get more or less the same results, but from the Qld border and down, without putting panels on a tilt frame, performance drops dramatically so your ROI will blow out.
Happy to answer any questions on this and note it’s based on real data so any discussions are around the data, not opinion.
Good luck with your solar systems.
