My customer is looking to replace his 5kw fan cooled inverter with a silent inverter, I'd like some advice on the cheapest silent brands please.

Sunsynk/Deye 5 kW inverter, the original ones had fans, but not the newer versions

I have the 5kVa SS, installed last year…it does have a small internal fan that kicks in when the DC temps exceed 55 degrees. But the noise is minimal when the fan kicks in…a slight hum to it. When the fan is off then you wouldn’t even notice the inverter. 

Goodwe. No fans on their domestic models. Big-ass heat sinks.

But they won't be absolutely, utterly silent. 

I have a 4.6kW ES series, and every now and then you hear relays clicking. But there's no continuous fan noise.

Thanks guys but Sunsynk, Deye and Goodwe are all expensive compared to Growatt and other forced cooled inverters.

18 minutes ago, Andre57 said:

Thanks guys but Sunsynk, Deye and Goodwe are all expensive compared to Growatt and other forced cooled inverters.

I have been running two Growatt SPF 5000 ES inverter in parallel for three years, they are very noisy indeed, but so far, no problems with them, running very well. So, if you can install them in a place where the noise will not bother you, for the price they are good inverters, I've heard lots of complains by other users, I personally after 3 years of use cannot complain.

Solis S6 5kW or 8kW. Also heat sink design. 

Does the Solis 8kW have a heat sink? I believe it has a fan

52 minutes ago, Dadoo123 said:

Does the Solis 8kW have a heat sink? I believe it has a fan

The Solis S6 Pro 8kW inverter utilizes an "intelligent redundant fan-cooling" system - The fans are designed to run when the inverter power (load or solar power into batteries) is greater than 3kW, or when the internal temperature rises above around 46°C.

Yeah. It will be running quite a lot in that case. Fox seems like a good alternative for the >6 kW inverters as they are silent. Their battery is a bit more expensive though and not widely supllied.