To those that can afford it, solar PV is often seen as an easy fix, a ‘get out of jail free’ card, a ‘set and forget’ solution that allows them to use energy freely, without cost to them or the planet. Consequently many households continue to unnecessarily consume huge amounts of energy on a daily basis, at considerable ongoing cost.
Solar PV does not warrant the carefree consumption of energy, whether the motives for getting it were financial, environmental, or both. For the vast majority of households with solar the energy they generate does not match 1:1 with the energy they are consuming, and a large proportion of their energy needs will still be met by the grid, and likely some far flung coal mine. This can be true even for households with large solar systems (ie 6kW+) that temporarily produce more power than they need for a period each day. In such scenarios (without battery storage), large amounts of energy is exported to the grid during the day, and then energy is bought back from the grid at night when there is no solar supplying the grid. If these import/export quantities are similar or in favour of exports, you could say “on paper” that the home is “net zero”, yet really this is a form of creative accounting… Battery storage seems to be a partial solution, yet the costs are still prohibitive to most and they have inherent environmental costs in terms of rare heavy metals.
So, I strongly believe that households need to do a lot more than simply install solar – to curb their underlying energy use – regardless of the size of their system.
Excerpt of a Scorecard Certificate for a home with solar. This home scored 10 stars largely due to their solar generation, but without it would have scored 3.9 stars. Despite scoring 10 stars this household would do well to improve the underlying energy demands of their home and appliances, ie aim to improve the underlying 3.9 star rating.
Why do some solar households still have high energy bills? (& large carbon footprint)
From my observations as an Energy Coach, for a variety of these reasons:
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- Solar energy generation isn’t evenly distributed through the day and night. So while you may be exporting power between 9am and 3pm, you may be importing it at all other times. And with Feed in Tariffs at all time lows, they no longer balance each other out financially.
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- High energy consumption in non-solar hours. The peaks in energy use for most houses are in the early morning and between 5-9pm in the evenings, when solar isn’t contributing. The more you use energy at these times, the larger your need to purchase energy from the grid. If you have electric storage hot water, it’s likely reheating in the early hours of the morning, because it helps the grid keep the coal power stations running.
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- Solar system not large enough, or compromised by shade / faults. If your energy demands are high and/or your solar small, the energy you’re generating may only be making a small dent in the balance. Especially if you have high energy demands like a pool, water pumps, large hot water system or electric vehicle charging.
- Generally high energy consumption. Some common causes include:
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- A large house with high heating/cooling needs, multiple fridges and the like.
- Energy hungry facilities like pools, spas, ducted air conditioning
- Poorly designed & built house with low thermal barrier
- Insufficient insulation, draught proofing, window coverings
- Inefficient appliances eg fridges, washing machines with low star rating.
- Energy hungry behaviours, eg using AC to keep a home unnecessarily hot / cool.
Unfortunately, many of these causes can be exacerbated if the household believes that their rooftop solar is providing for, or offsetting, their energy demands. In other words, they don’t attempt to remedy the causes of their high energy use because they don’t think they need to, or it’s too much work.
What else can households with solar do?
I’m particularly fond of this saying:
“The greenest power is the one that doesn’t need to be produced”
That is, reducing the total energy your home consumes is by far the best way of reducing your carbon footprint. In financial terms, the best way to lower your energy bills is to use less energy, even if you have solar.
There are numerous ways to lower your energy use, and they don’t have to mean you “go without” or lower your standard of living. In fact the term “energy efficiency” has a negative connotation for many people because they associate it with just that – energy rationing, and labour-intensive behavioural change like switching appliances off at the wall and turning out lights when you leave the room. These actions can help if you have the motivation, but there are so many others you can take that will have a greater impact and don’t require you to lift a finger once in place. Some broad examples:
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- High tech retrofits: eg energy efficient hot water systems and heat pumps, LED lighting.
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- Low tech, low cost retrofits: window coverings to control heat, draught proofing, ceiling and floor insulation to improve the home’s thermal barrier.
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- Load shifting: altering the times that energy hungry appliances are used, to coincide with solar production, eg pool pump timers, heating hot water, using timers on dishwashers and washing machines.
What if I don’t have solar?
If you don’t or can’t have solar, never fear, the same principles above apply and there is so much you can do to create a low-energy home, reducing your energy bills and carbon footprint. See below.
Where to start, and how to get help?
Each home is so different, there are multiple variables to factor in if you want to find the most effective way to create a low-energy home. The best solutions will depend on your budget, your inclination for behavioural change, and the inherent characteristics of your building shell and appliances.
The first step I’d recommend is to identify what is likely to be using the most energy in your home, and find out ways to reduce it. That is, start with the low hanging fruit, if it is something within your budget.
Of course, I’d also recommend you get professional support from an Energy Advisor like myself! An energy consultation can take the guess work out of it, identifying the contributors to your energy usage and then recommend options to address them. In some cases I can even do the remedial work for you. Here’s a link to my webpage listing the services I provide: https://homeenergyadvisor.com.au/services/
https://homeenergyadvisor.com.au/services/: Why solar is not enough
The best first step to take is to have a Scorecard Assessment of your home, which assesses the thermal envelope and fixed appliances of the building, provides recommendations on the most effective remedial actions, and provides you with an energy star rating and Scorecard Certificate. If that isn’t within your means I can do a more informal, observational assessment of your home, along with analysis of your energy bills and any solar monitoring you have.
Seb Crangle