There are a lot of contributing factors when deciding to make the switch to solar, but the most important is determining whether your property is suitable. Most of us know the basics of what makes our property suitable, but unfortunately there is more to it than meets the eye.
When determining if solar can be installed on your roof there are three mains things to consider; the integrity and material, size and pitch.
The most obvious giveaway in determining if your roof is suitable for solar is rust. If your roof is rusted it is a safety issue and shouldn’t be installed on. Installing solar on a rusty roof could damage the integrity of the roof and often leads to leaks.
The type of material your roof is made from also plays a key role in determining if solar can be installed. Common types of aluminium sheeting can be soft and damage easily. Most solar companies will avoid installing on these roofs as it’s not worth risking potential damage in the future for the customer. Other materials such as decromastic tiles and asbestos roofs are also avoided by most companies.
If your home has a small roof or one with a number of different aspects it can be difficult to install a solar system. A small roof can still have solar installed but will limit the size of your system and ultimately limit your potential savings.
The pitch of your roof may also prevent you from making the switch to solar. Most solar companies will not install on a roof with a pitch over 30 degrees as it is a safety risk for the installers.
You may think that because the sun shines through your house all day that you don’t have any shading issues but unfortunately it’s more complex than that. Trees are marvelous things and they can cast shade further than you think. There’s a chance that the large tree in your neighbour’s backyard could shade parts of your roof as well. It is important to identify any trees surrounding your property that may cause shade.
Trees are not the only thing that could cause shading issues on your roof. Vent pipes and TV antennas can also cause shading. You might be thinking that TV antennas aren’t very big and they couldn’t affect production that much. However, all panels produce equal to the lowest producing panel. Meaning that if there is shading on one panel, it could affect all other panels in that string.
Direction of panels
The direction that your solar panels will be placed will also affect your solar production. The ideal property for solar production has enough roof space to place all panels facing north.
Having all panels facing north is the optimal panel layout as panels facing north produce the most electricity overall. North facing solar systems are great for people that are home during the day as these customers can run appliances in the middle of the day when production is at its peak.
West facing panels produce about 12% less electricity than panels facing north. Panels facing west will have lower production in the morning but higher production in the afternoon and peak just after noon. West facing panels are ideal for people that are home and use their power in the afternoon.
Solar systems with a north-west orientation will produce approximately 5% less electricity overall than north facing systems. The production throughout the day will be that of north and west facing panels but will produce slightly less in the morning and more in the afternoon.
East facing panels are similar to west facing panels and will produce approximately 12% less than north facing panels. Panels facing east will have lower production in the afternoon but higher production in the morning. East facing is ideal for people who are home in the morning.
North-east facing panels will produce 5% less electricity than north facing overall.
East and West Facing
Placing panels east and west will give a similar result to east facing and will produce approximately 12% less than north facing. The east/west split can often result in a more consistent output of electricity throughout the day compared to other orientations. East/west orientation is ideal for people that work during the day as there is high production in the morning and afternoon when people are likely at home.
South facing is the worst direction that panels can face. Depending on your location, south facing systems can produce up to 28% less electricity than north facing panels. Installing solar on the south facing roof can be done. It is just important to be aware that production will be dramatically lower, especially in the winter months.
It’s important to be realistic about how much solar could save you. There was a time during the solar boom when feed-in tariffs were so high that some customers are lucky enough to receive credits instead of debits from their electrical retailer. Unfortunately, those days are gone but it doesn’t mean you still can’t significantly reduce your bill. You just probably won’t eliminate it completely. For the majority of people solar is a great option and will save you a lot of money. For the lucky ones that already have lows bills though, it might be a different story.
What if I have small bills?
Let’s say your electricity bill is $300 a quarter. Approximately $90 of that is in service charges alone. That means your actual electricity bills is only $210 a quarter and you’re using approximately 9kWh of power each day.[i] If the majority of that consumption is at night and you can’t change your habits, then solar probably isn’t the way to go. However, if most of your consumption is during the day, let’s look at the return on investment.
Say you purchase a 3kW system for $3,500. That system will save you approximately $1.95 a day. This is on the assumption that you will consume 6kWs of the 12kWs of power your system produces and save yourself $1.50. You will then receive the solar FiT for the energy you didn’t consume and receive a credit of $0.45 per day. Giving you a total of $1.95 per day and approximately $175 a quarter. Now, saving $175 a year is still awesome but it’s a five-year return on investment and we usually like to see it sooner. These results don’t mean it’s a waste getting solar, it’s just important to look at what your true consumption is.
What if I have large bills?
Let’s take a look at the increased benefits if you have a high bill. If you bill is $800 a quarter, minus the service charge of $90 then your quarterly usage is $710 and you’re using approximately 31kWs a day.[ii] Say you purchase a 6kW system for $6,500 and your system produces approximately 25kWhs a day. We know that you consume 31kWhs a day so let’s assume that 50% of that is at night so during the day you use 15kWs. You will save approximately $3.75 a day from the power you did not buy from the grid (15kWh x 0.25c). For the 10kWs you didn’t use, you will receive the solar FiT and earn an additional $0.73 (10kW x $0.0736). Giving you a daily savings of $4.48 and a yearly saving of approximately $1,600.
Having a small bill doesn’t mean solar won’t save you or you shouldn’t do it. It’s just important to look at all the factors that might affect your production or potential savings. Determining if your property and usage is suitable for solar is one of the best first steps you can take on your renewable energy journey.
[i] Based on the calculation: $210/90 days = $2.33 per day. $2.33 per day / 0.25c/kWh = 9.33kW per day.
[ii] Based on the calculation: $710/90 days = $7.88 per day. $7.88 per day / 0.25c/kWh = 31.55kW per day.