2-in-1 function


Thermal performance testing for solar air collector; Pressure drop test; Time constant test; Visual inspection; Internal pressuretest; Rupture or collapse test; Stagnation temperature; Exposure test; Externalthermal shock; Internal thermal shock; Rain penetration; Freeze resistance; Mechanical load; Impact resistance test using steel ball; Final inspection. All above listed tests of the standard EN12975-1:2006+A1:2010 and ISO 9806:2017 were passed successfully in accordance with the criteria.


The Solar Keymark is a voluntary third-party certification mark for solar thermal products, demonstrating to end-users that a product conforms to the relevant European standards and fulfills additional requirements. It is widely spread across the European market and beyond. The Solar Keymark is a quality label.

Standard function

Refund policy

We have a 15-day return policy, which means you have 30 days after receiving your item to request a return.
To be eligible for a return, your item must be in the same condition that you received it, unworn or unused, with tags, and in its original packaging.
You can always contact us for any return question at info@nakoair.net.
Damages and Exchanges
Usually, we will send you parts for exchange. Because the cost of returning and re-shipping is high. Please do not return the goods if there is a little damage or small quality problem.
Refunds
We will notify you once we’ve received and inspected your return, and let you know if the refund was approved or not. If approved, you’ll be automatically refunded on your original payment method. Please remember it can take some time for your bank or credit card company to process and post the refund too.