Store policies

The complete terms for buying from Serin Labs, in plain language. Last updated October 11, 2026. For the site itself, the flash tool, and the firmware, see the Terms of Service.

Ordering and payment

You can purchase through either of the following channels. The applicable terms differ by channel.

• Directly from serin-labs.com. Shopify processes the checkout, and Serin Labs does not receive your card details. This is the recommended purchase method.
• Through our Etsy shop. Etsy handles checkout and payment, and those orders are covered by Etsy Purchase Protection. Purchase Protection applies to Etsy orders only.

Shipping

• US orders of $35 or more ship free when placed directly on this site. Free shipping covers up to $8 of postage. If the rate for your order is higher, for example because you choose a faster service, the shipping charge is shown at checkout. Below that threshold, the shipping rate is calculated at checkout. Etsy orders ship at the rate Etsy shows at checkout. Everything ships from New Jersey.
• Processing time: Controller and cable orders normally ship within 1–2 business days. The Serin Link is built to order and ships within 1–3 days. US delivery usually occurs within a few days after shipment; the estimated delivery date appears at checkout.
• The Serin Link ships to US addresses only. It is sold on this site and not on Etsy.
• International orders: Orders outside the US ship at the carrier rate shown at checkout; any duties or import fees on delivery are the buyer's. Serin Labs is not responsible for customs-related delays. US buyers do not owe duties or import fees.

Cancellations

You can cancel an order within 12 hours of purchase for a full refund. After that period, the order may have entered processing. For direct orders, use the contact form and include your order number; we will confirm whether cancellation is still possible. For Etsy orders, message the shop.

Returns and exchanges

• Returns and exchanges are accepted within 30 days of delivery on both channels.
• Direct orders: use the contact form with your order number to receive the return address.
• Etsy orders: message the shop on Etsy, which keeps Purchase Protection in place.
• Items must be returned in the condition in which they were received, with the included cable and any accessories. Installing firmware does not affect return eligibility.
• Return shipping is paid by the buyer, except for defective or incorrect items (see below), where we cover it.
• A 20% restocking fee is deducted from the refund on a returned item. It does not apply to an exchange, to an item that arrives damaged, defective, or incorrect, or to a controller that does not fit an indoor unit the model checker listed as compatible (see below).
• Serin Link returns include the whole box: the assembled Link, the USB-C to USB-C cable, the USB-C wall charger, and the printed instructions.
• There is no repair service and no replacement parts are sold, so a failure covered by this page or by the limited warranty is settled by replacing the product or refunding it. The limited warranty makes one exception, for a failed accessory such as the Serin Link's charger, which is replaced on its own.
• A Serin Link ordered as a bundle with a controller is returned complete. If you would rather return only one item out of a bundle, contact us first and we will tell you what we can do.

If the controller does not fit your indoor unit

Use the model checker before ordering. If the model checker listed your indoor unit as compatible and the controller turns out not to work with it, return the controller within the same 30-day period for a full refund with no restocking fee. If the checker did not list your unit as compatible, or you ordered without checking, the return is handled like any other and the 20% restocking fee applies. Installing firmware does not affect return eligibility.

Please include the indoor unit's model number and a description of the compatibility issue. Confirmed results are added to the public compatibility list to help other customers check before ordering.

Refunds

Refunds are issued to the original payment method after the return has been received and inspected, normally within a few business days. The payment processor determines when the refund appears on your card or bank account: Shopify for direct orders and Etsy for Etsy orders.

Damaged, defective, or incorrect items

If a controller, cable, or sensor arrives damaged, does not function, or differs from what you ordered, you may choose a replacement or a full refund. Serin Labs covers shipping in both directions. If a controller does not respond, first review the troubleshooting guide; a charge-only USB cable is the most common cause. Then provide your order number and a description of the problem through the contact form for direct orders or an Etsy message for Etsy orders.

Warranty

Every product carries a one-year limited hardware warranty against manufacturing defects, on top of the 30-day return window above and the commitment on damaged, defective, or incorrect items. What it covers, what it excludes, and how to make a claim are set out on the limited warranty page. The firmware is free of charge and does not require a subscription.

Adding a third-party accessory to HVAC equipment may affect the equipment manufacturer's warranty terms; see safety and installation.

Support

Support is free and comes from the same shop that builds the hardware. Use the contact form for anything to do with an order; we reply within 2 business days. Discord is the fastest place to ask a setup question, and a suspected firmware bug belongs on GitHub, where it stays tracked. Official support covers:

• Serin Labs hardware: the controller, the CN105-to-Grove cable, the sensor bundle, and Serin Link.
• The official firmware builds, the browser flash tool, and pairing.
• The public serin_link ESPHome component and its documented example configuration.
• Reasonable setup guidance for getting a Serin Labs product working in your system.

The following fall outside official support:

• Bugs in third-party ESPHome components.
• Custom YAML architectures.
• Controller hardware you built yourself, and boards you sourced elsewhere. We will still help you tell a hardware problem from a firmware problem.
• General Home Assistant administration.

Disputes and questions

If an issue remains unresolved, use the contact form or message the shop for an Etsy order. We reply within 2 business days and will work with you to resolve the problem. Etsy orders remain eligible for Etsy's dispute process; direct orders are covered by the payment provider's dispute process.