Ask an Australian solar installer what their customer acquisition cost is and you will get a number, usually somewhere between $150 and $400 a lead before conversion, rising every year. Ask them what they did with the two thousand customers they have already acquired, installed for, and been paid by, and the answer is usually silence. The database sits in the CRM or a job management tool, contacted never, while the marketing budget fights strangers for attention at full price.
This is the strangest gap in solar marketing, because the installed base is not just an audience, it is the qualified audience: people who own a roof, chose you once, and are steadily accumulating reasons to buy again. Batteries, EV chargers, system upgrades, servicing and referrals all live in that list. This guide is the email program that turns it back on, built for the realities of a trade business rather than an ecommerce brand.
Why the installed base is worth more than new leads
Run the arithmetic on a typical installer with 1,500 past customers. If even 10 per cent add a battery over the next three years, at current battery job values that is a seven figure pipeline, from people who already trust you, at an acquisition cost of essentially nothing. Compare that to buying the same battery pipeline as shared leads at current per lead prices, competing against four other installers on every quote, the economics we broke down in aggregator leads versus direct.
The timing is also unusually good. Battery economics shifted hard with the federal battery program, and every solar only customer in your database installed before it is now sitting on the exact configuration, existing panels, no storage, that batteries were made for. Meanwhile EV ownership keeps climbing, and a customer who bought an EV needs the charger conversation, ideally from the installer who already knows their switchboard, the opportunity we sized in EV charger installation marketing. Your database segments itself by what each customer bought and when, which is targeting no ad platform can sell you.
The legal ground rules, briefly and seriously
Australian email marketing runs under the Spam Act, and the rules are workable if you respect them: send only with consent, express or reasonably inferred from an existing business relationship, identify your business clearly, and include a working unsubscribe that you honour promptly. Past customers with whom you have an ongoing relationship are generally the safest audience in email, but purchased lists are exactly the opposite, and adding scraped or bought addresses to your customer list poisons both. The plain English guidance on the ACMA website is worth ten minutes of your time before the first send, and the compliance instincts you already run for advertising claims, the same ones covered in our solar ad compliance guide, apply to every claim in every email.
The program: five emails a year, each earning its place
The failure mode for trade business email is the monthly newsletter that starts enthusiastic, decays into recycled filler, and dies by August. The design principle that survives contact with a busy business: fewer sends, each with a reason to exist. Five well built emails a year beat twelve mediocre ones on every metric, including the one that matters most, not being unsubscribed from.
The system anniversary email. Sent on each customer’s install anniversary, automated once and running forever. What their system likely generated this year, a prompt to check their inverter data, a reminder of the workmanship warranty they hold, and one line inviting them to reply with any issue. This is the email that maintains the relationship all the others draw on, and because it is genuinely useful, it trains the base to open you.
The battery economics email, segmented. To solar only customers, sent when something real changes: rebate movements, a tariff shift, a new price point you can install at. The content is the honest arithmetic for a system like theirs, not a sale banner. Battery messaging that respects intelligence outperforms urgency theatre with this audience, the same finding that runs through our battery storage playbook.
The EV email, to everyone. Once a year, or triggered when charger pricing or your offer changes: what home charging costs installed, what solar integrated charging saves, and a soft question, thinking about an EV, because the reply data itself builds your pipeline for the years ahead.
The service and health check email. Panels degrade quietly, inverters fail loudly, and almost nobody offers customers a structured way to care about it. A paid or free health check offer, positioned around protecting output rather than finding problems, generates service revenue and, more importantly, puts your people back on roofs where quote opportunities live.
The referral email. Once a year, plainly: most of our work comes from referrals, here is how to send a neighbour or friend to us, and here is what we do to say thanks. Referred solar customers close at multiples of cold lead rates and cost nothing to acquire. The ask works because the other four emails made you a business worth referring, which is the same reputation flywheel we described in solar reviews and reputation management.
The operational reality for a trade business
Tooling is the easy part: any mainstream email platform at the entry tier handles this volume, and most job management systems export the customer list with install dates, which is the only segmentation field the whole program strictly needs. The genuinely hard parts are two.
Data hygiene: the list needs install date, system details and email captured as a habit at handover, not reconstructed annually in a heroic spreadsheet weekend. Make email capture and a consent line part of the handover checklist this week and the future program builds itself.
And the writing: the emails should sound like the owner, not like marketing. Plain subject lines that say what the email is, your battery numbers this year, rather than clickbait. Short, specific, one topic, one action. The test for every send is whether a reasonable customer would think that was worth opening, because the alternative reading, they are spamming me now, spends trust you earned on roofs.
The first ninety days, if you are starting from nothing
Most installers reading this have the classic starting position: customer data scattered across a job system, an accounts inbox and a filing cabinet, and no email tool. Here is the realistic ramp.
Weeks one and two are the list build. Export every completed job from your job management system with customer name, email, install date and system details. Accept that the export will be imperfect, dedupe it roughly, and do not let missing data stall you: a list with gaps that exists beats a perfect list that never ships. While that happens, add two lines to your handover checklist, confirm the email address and a sentence of consent for occasional updates, so the list grows clean from here.
Weeks three and four are setup and the first send. Pick any mainstream email platform at the entry tier, import the list, and send the re-introduction email: a short, personal note from the owner. We installed your system, here is what we are seeing systems like yours generate this year, we are around if anything needs attention, and you can unsubscribe below. This email does three jobs at once: it validates the list as bounces reveal dead addresses, it re-establishes the relationship legally and socially, and its replies, which will surprise you, are immediate service and battery enquiries from people who thought of you the moment you gave them the chance.
Months two and three run the first real cycle: the battery economics email to solar only customers in month two, the service health check offer in month three, with the anniversary automation built in the background so it runs forever after. By the end of the quarter you have a functioning channel, a bounce cleaned list, reply generated quotes in the pipeline, and the data to decide cadence from evidence rather than theory.
The whole ramp costs a few hundred dollars in tooling and perhaps three working days spread across the quarter, which is less than most installers spend acquiring four leads. It is the rare marketing project where the main risk is not failure but the discovery of how much revenue was sitting in a spreadsheet the whole time.
Measuring it like a channel, not a hobby
Track four numbers per send: opens as a health signal, replies and clicks as intent, jobs quoted from the send, and revenue closed. Tag every job that originates from an email in your job system, because the program justifies itself on quoted work, not on open rates. A realistic expectation for a clean list of past customers: open rates far above retail norms, single digit percentage reply and enquiry rates on the battery and service sends, and a cost per generated quote that embarrasses every paid channel you run. Review the program twice a year against those numbers next to your cost per lead benchmarks, and the budget conversation tends to end quickly.
Frequently asked questions
Is it legal to email my past solar customers?
Generally yes, under the Spam Act’s inferred consent from an existing business relationship, provided every send identifies your business and carries a working unsubscribe you honour. Purchased or scraped lists are the opposite case and not worth the risk. When in doubt, the ACMA’s guidance is short and clear, and adding an explicit consent line at handover removes all doubt for future customers.
How often should a solar installer email their customer base?
Four to six times a year, each send with a concrete reason: anniversary and system health, battery economics when something real changes, EV charging, a service offer, and one referral ask. Fewer, better emails protect the asset; a forced monthly newsletter erodes it.
What results should I expect from a battery cross sell email?
From a clean list of solar only customers, single digit percentage enquiry rates per send are realistic, which on a base of one to two thousand customers means a meaningful battery quote pipeline at near zero acquisition cost. The close rate on those quotes runs well above cold leads because the trust and the site knowledge already exist.
I never collected emails properly. Is it too late?
No. Start capturing at every handover and service call from this week, and backfill opportunistically: warranty registrations, invoices and job records usually recover a surprising share of past addresses. A list of five hundred genuine past customers outperforms most paid campaigns an installer runs.
Should the emails come from the business or the owner?
From a named person, usually the owner, in plain language. Trade customers respond to the person who was accountable for their roof, not to a brand voice. Plain subject lines describing the content beat clever ones with this audience on every metric that matters.
What subject lines work for solar customer emails?
Plain ones that state the content: your system’s third year, in numbers. Battery prices moved, here is the maths for your setup. A free health check for systems installed in 2022. This audience gave you their address because you put panels on their roof, not because they wanted marketing, and subject lines that respect that read as service while clever ones read as spam. The reliable test is whether the subject line would sound normal said aloud to the customer at their front door. Curiosity gaps, urgency theatre and emoji all measurably increase unsubscribes with trade audiences, and every unsubscribe is a battery, charger and referral pipeline permanently switched off for the sake of one open.
How does email fit with the rest of solar marketing?
It is the highest margin channel you can run because the audience is already paid for. It does not replace acquisition, search, reviews and AI visibility still fill the top of the funnel, but every acquired customer now enters an asset that keeps producing batteries, chargers, service and referrals for a decade. Acquisition without retention is renting revenue; the database is where you stop renting.
