Why Adding Solar to Your Mortgage is a Smart Move
Considering solar for your new home? There's a strong case for adding it to your mortgage before you build, rather than retrofitting it later. Chief among the reasons: you could be cash flow positive from day one.
A quick guide to solar. Here's why you should consider it before you build.
You'll pay a little more on your mortgage each month if it includes solar, but you'll also start saving on your energy bills straight away. For most new builds, the savings outweigh the added repayment, which means solar can put money back in your pocket every single month, not just over the life of the system.
For most new builds, adding solar at the build stage means you are putting money back in your pocket every single month.
Here's what that looks like using Carlisle's most popular system size, the 6.6kW, based on the current average Victorian mortgage of $675,000 and a variable rate of 6.67% per annum over 30 years:
Added monthly mortgage repayment: about $47
Monthly electricity saving: about $117
Net monthly benefit: about $70 back in your pocket, every month
A 6.6kW system currently costs somewhere between $5,500 and $9,000 fully installed, according to comparison site Choice, depending on panel brand, inverter quality and how straightforward your roof is to work with. The figures above are based on a mid-range cost of around $7,250, added to your loan over the full term. Here's how that plays out across the full price range:
| 6.6kW system cost | Added monthly repayment | Monthly electricity saving | Net monthly benefit |
|---|---|---|---|
| $5,500 (low end) | ~$35 | ~$117 | ~$82 |
| $7,250 (mid-range, used above) | ~$47 | ~$117 | ~$70 |
| $9,000 (high end) | ~$58 | ~$117 | ~$59 |
Note: these figures are a guide only. Every build, energy plan and household is different, so speak with your financial adviser for advice specific to your circumstances.
It's also worth knowing that a growing number of new homeowners are pairing their solar system with a home battery, storing the power generated during the day to use after the sun goes down, instead of paying peak evening rates for grid power. It's a bigger decision upfront, but it's opening up even more savings over time as battery technology improves and prices continue to come down.
Heating and cooling account for a meaningful share of household energy use, so a solar and battery system is the optimal way to reduce ongoing costs.
Why more people are switching on to solar
Solar has moved well past early-adopter territory. More than 4.3 million Australian households now have rooftop solar installed, and the combined capacity of the country's household systems has overtaken its entire coal-fired power fleet, according to the Clean Energy Council. Rooftop solar generated 14.2% of Australia's electricity in the second half of 2025, up from 13.4% the year before.
Batteries are the newer part of that story, and they're moving faster again. Australian households installed 183,245 home batteries in the second half of 2025 alone, more than the total installed across the previous five years combined. What used to be a niche add-on is quickly becoming a standard part of how new homes are being built and specified.
Built for a harder climate, in both directions
There's a practical reason solar and batteries are gaining ground beyond the financial case: Victoria's weather is becoming more demanding at both ends of the year. Victoria's Climate Science Report, compiled by CSIRO and the Victorian Government, confirms that the number of hot days and very hot days has continued to increase across the state, with the most extreme days showing the largest jump over the past decade. That extra heat load doesn't just affect your comfort. Victoria's electricity grid hit an all-time peak demand record during extreme heat in January 2026, according to the Australian Energy Market Operator, as millions of homes cranked up their air conditioning at once.
The benefits of adding solar to your build are both financial and practical.
As anyone who’s endured a Melbourne winter knows, heating still accounts for a meaningful share of household energy use through the cooler months. A solar and battery system doesn't just take the edge off summer power bills. Stored daytime power can be drawn down on a cold winter evening too, which is part of why it's increasingly viewed as a resilience decision as much as a savings one.
But positive cash flow isn't the only smart reason to go solar now:
Cheaper & easier installation
The most cost-effective time to install solar is when you're building your home. Retrofitting a system later is always going to be more complicated, time-consuming and expensive.
Get the best placement
When you include solar at the planning stage, you can optimise the position and angle of your roof panels to achieve maximum solar gain. You can also plan around other elements you might want on your roof, like a satellite dish, TV aerials or an air-conditioning unit, so nothing ends up blocking or overshadowing your panels.
Choose the system size that fits your household
Carlisle now offers solar in four sizes: 6.6kW, 8kW, 10kW and 13kW. The 6.6kW used in the example above is the most common starting point, but it's not a one-size-fits-all decision. If you're running a pool, multiple air conditioners, or planning for an EV down the track, it's worth talking to your consultant about stepping up to a larger system from the outset.
Fully concealed wiring
It's far quicker, easier and cheaper to run wiring before your walls have been gyprocked. It also means there won't be any visible solar cables in your home, for a neater, more streamlined appearance.
Guaranteed quality installation
When you include solar with your new Carlisle home, we offer guaranteed, quality installation by Carlisle-approved suppliers, giving you peace of mind that the system will be installed properly and last the distance.
Increase the value of your property
Solar remains one of the features most prized by home buyers. Including it in your build before construction means your home is more appealing to future buyers from the day you move in, with panels integrated cleanly into the roofline rather than added on top as a visible retrofit later.
Keen to learn more about including solar in your new Carlisle home? Enquire today via our website or call 1300 535 416 to speak to one of our friendly sales consultants.
