The quality is good, I recommend it. The staff is very responsive and answer all questions. A little about the product: - Works with the app: Smart Life. - It works very well down to -20°C. It's almost ineffective at -25°C to -33°C, so it's best to turn it off. It was tested down up to -33°C. The defrosting works perfectly. - When the circulation pump 25-60/180 is under heavy load, the unit protection is triggered (for example, when using antifreeze in the cold or the manifold). Therefore, using a additional buffer tank with circulation pump will reduce the load on the first pump.