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Private label, ODM and OEM sound alike but split the work, the risk and the certification differently. This guide explains each model, what a factory can customise, how certification follows your brand, and what to agree before the first order.
Short answer: OEM solar water heater sourcing means a factory builds solar water heaters, collectors or tanks that you sell under your own brand. Private label uses the factory’s existing design with your label, ODM adds changes to a factory design, and full OEM builds to your own drawings. The factory handles production and testing, while you own the brand, the market approvals in your name, and the after-sales promise. Decide the model first, because it sets cost, lead time and certification.
Key Takeaways
- Private label, ODM and OEM differ in how much of the product design you own; pick the least custom model that meets your market.
- Certification follows the product and the legal entity, so plan the OEM or private-label certificate before you print the brand.
- Agree samples, drawings, labels and packaging in writing before the first order.
- Put warranty, spare parts and who handles claims into the contract, not the brochure.
What Is the Difference Between Private Label, ODM and OEM?
The difference is how much of the product design is yours: private label changes the label, ODM changes parts of the design, and OEM builds to your specification. In practice factories use the terms loosely, so write down what each side will do.
| Model | What you provide | What the factory provides | Best for |
|---|---|---|---|
| Private label | Brand, logo, label and packaging artwork | Existing product, unchanged, with your branding | Fast market entry with the lowest development cost |
| ODM | Requirements, colours, sizes, features and artwork | Adapts an existing design and builds it | A distinctive range without owning new tooling |
| OEM (build to specification) | Drawings, specification and approval samples | Builds to your design, with your tooling where needed | Established brands with their own engineering |
Most new brands start with private label or light ODM, because it avoids tooling cost and shortens the path to certified product. Move to deeper customisation once the market and volume are proven.
What Can a Solar Water Heater Factory Customise?
A solar water heater factory can usually customise the logo, labels, packaging, absorber coating, collector and tank size, frame colour and profile, and technical documentation. Millionsun lists exactly these as its OEM items, so they are a sensible baseline for any supplier.
- Brand and labels: logo, product label, type plate and serial number format.
- Packaging: carton or crate design, marking and language of the manuals.
- Absorber coating: black or blue selective coating, chosen by cost and climate. Our absorber sourcing guide covers the trade-offs.
- Size: collector and tank dimensions within the factory’s tooling range.
- Frame: colour and profile of the aluminium frame, including silver or black finishes.
- Documentation: manuals, datasheets and installation instructions in your brand format.
Ask what is standard and what triggers a higher minimum order. For Millionsun, the minimum order for OEM and ODM work depends on the level of customisation; confirm it per model in the quotation.
How Does Certification Work for a Private-Label or OEM Product?
Certification attaches to the product and the certificate holder, so a brand owner who wants the certificate in its own name must apply for an OEM certificate based on the manufacturer’s tested product. DIN CERTCO, which issues Solar Keymark certificates, explains the process in its solar thermal certification FAQ.
According to that FAQ, a retailer that wants the Solar Keymark for certified products under its own name needs to apply for the Original Equipment Manufacturer (OEM) certificate and provide:
- an original application for every certification, specifying the registration number of the applicable Keymark certification;
- written confirmation from the manufacturer (the certificate owner) that the certification body may access the test report;
- a rewritten test report with the name of the OEM customer and a new test report number;
- the type plate and the installation or assembly instructions; and
- the Solar Keymark data sheet from the test lab.
The same FAQ notes that the documents can be obtained from the test lab that performed the first test, and that the Keymark certificate is valid for five years, with an extension possible if the factory inspection and physical inspection are positive. The products certified include solar collectors, solar thermal systems and storage water heaters for solar plants.
Check any certificate you are shown in the public Keymark certificate database. Other markets have their own rules, so confirm with the relevant body whether a private-label or OEM listing is allowed for SRCC, WaterMark or AS/NZS 2712. Our guide to collector certification by market compares the schemes.
What Are the Steps in an OEM Solar Water Heater Project?
An OEM project runs in six steps, from scope to mass production, and the sample approval is the step that protects the whole order. Skipping or rushing it is the most common source of disputes.
- Define the scope: product type, sizes, target markets, certificates required and annual volume.
- Request quotations: send the same written specification to each supplier so the offers can be compared.
- Approve artwork and drawings: logo, labels, type plate, carton design and manuals, signed off before samples are made.
- Order and test samples: samples of the exact model with your branding; test them yourself, including pressure and fit.
- Sign the contract: model, specification, price, Incoterm, lead time, payment, warranty and inspection terms.
- Produce and inspect: production against the approved sample, with inspection before shipment and records kept by serial number.
Ask for sample lead time and quantities. Millionsun samples start at 1–2 units, and standard lead time is 15–20 days. OEM configurations may take longer, so confirm the lead time per project in the quotation.
What Risks Should an OEM Brand Manage?
The main risks are unclear ownership of tooling and designs, quality drift between samples and production, certificates that do not match the shipped model, and unclear warranty responsibility. Each can be handled in the contract.
| Risk | How it shows up | Contract or process control |
|---|---|---|
| Tooling and design ownership | Factory sells the same custom design to others | State who owns custom tooling and drawings; agree exclusivity terms in writing |
| Production differs from sample | Parts or coating change after approval | Freeze the bill of materials; require notice of any change; inspect before shipment |
| Certificate mismatch | Certificate covers a different model or holder | Match model, holder and validity to the shipped product; verify in the public database |
| Warranty confusion | End customer claims go to the wrong party | Define who handles claims, what the factory covers, and the claim documents needed |
| Spare parts supply | Parts unavailable for custom items | Agree a spare parts list and support period at the start |
| Intellectual property | Brand or design copied | Register the trademark in your market; use a written NDA where designs are shared |
Our guide to the questions to ask a solar water heater factory gives a longer checklist for the first order, and the quality-control checklist shows what to verify at the factory.
Should You Buy Complete Units, SKD or CKD for Your Brand?
Buy complete units to enter a market quickly, and move to SKD or CKD once volume is steady and you want local assembly, lower freight volume or local content. Millionsun supplies complete units, SKD, CKD and individual components.
Complete units carry the lowest operational burden: the factory assembles, tests and packs the product, and you brand and sell it. SKD and CKD kits shift assembly and testing to you, so they need a workshop, trained staff and testing equipment. Our guides to CKD, SKD and complete flat plate collectors and to a collector assembly plant cover the decision in detail.
How Millionsun Runs OEM and ODM Projects
Millionsun is an OEM-first solar water heating manufacturer in Dongguan, Guangdong, producing flat plate collectors and solar water tanks since 2006 on an 8,000 m² site with more than 80 employees and 6 automated production lines. Collector capacity is 20,000 m² per month and tank capacity is 4,000 units per month, with absorber coating done in-house.
OEM and ODM customisation covers logo, labels, packaging, absorber coating (black or blue), collector and tank size, frame colour and profile, and technical documentation. Every collector and tank is 100% pressure tested before shipment, collectors operate at 12 bar and are tested at 20 bar, and each collector has a unique serial number linked to batch, production date and QC records. Solar Keymark was obtained for collectors in 2008 and again for collectors and systems in 2011; ask us for the certificate detail for the model you plan to brand and the OEM certificate process.
Tanks carry a 5-year warranty; for collector warranty, confirm the terms for your model in the quotation. Spare parts are supported for the full product lifespan. See our pages for solar water heater brands and OEM and ODM services.
Planning a private-label or OEM solar water heater line?
Millionsun is a source factory in Dongguan, China, producing flat plate collectors, solar water tanks and complete systems since 2006. We supply complete units, SKD, CKD or components, with OEM and ODM options for logo, labels, packaging, coating colour, size and technical documentation. Send your target markets and model list and we will reply within 24 hours.
Request a QuoteFrequently Asked Questions
What is the difference between OEM and ODM for solar water heaters?
OEM builds a solar water heater to the buyer’s own specification, while ODM adapts and builds an existing factory design for the buyer’s brand. ODM is faster and cheaper to start because the base design is already tooled and tested.
Can I put my brand on a solar water heater that already has a Solar Keymark certificate?
You can put your brand on a certified solar water heater, but for the certificate to carry your name you need an OEM certificate based on the manufacturer’s tested product. DIN CERTCO lists the documents required, including the manufacturer’s written consent and a rewritten test report in your name.
What is the minimum order for OEM solar water heaters?
The minimum order for OEM solar water heaters depends on how much of the product you customise, so there is no single figure. Ask the supplier to state the MOQ per model and what customisation triggers a higher quantity.
How many samples should I order before an OEM project?
Order one or two samples of the exact branded model before an OEM project, which is the usual sample quantity. Test them against the approved drawings, pressure test one unit and open one to inspect insulation, seals and welding.
Who is responsible for warranty claims on private-label solar water heaters?
The brand owner is normally responsible to the end customer for warranty claims on private-label solar water heaters, and the contract defines what the factory covers in return. Agree the claim documents, the response time and the spare parts policy before the first order.
Bottom Line
- Choose private label, ODM or OEM by how much design you need to own, and start with the least custom model.
- Plan the OEM certificate and test report in your name before you print the brand.
- Approve artwork, drawings and samples in writing, then freeze the specification.
- Put warranty, spare parts, tooling ownership and inspection terms into the contract.