Typically, the power rating is not too important unless you are planning to use the system for Public Address type applications (i.e. where you are having to fill a hall with loud music for long periods).

If you are planning very high sound levels then you should stick to the recommendation by Sonos to use speakers rated at 200W. But I don’t think you would enjoy the sound of ceiling speakers running at, say, 100W in a typical room, because you are likely to find that the whole ceiling starts moving at those levels.

That’s not to say that you cannot fit very high powered speakers into ceiling spaces - but most people seem only to want ceiling speakers for “background music” type use, where the power rating is not critical.

acambitsis,

There are no universally accepted standards used for assigning speaker power ratings. Actually, more speakers damaged by low power amplifiers than high power amplifiers. In terms of raw energy, bass requires most of the energy. If an amplifier is pushed beyond its power rating in an attempt to boost the bass, the amplifier will enter a gross distortion mode that is rich in high frequency energy. This is often referred to as “Clipping” and the change in energy balance stresses the tweeter. While it seems counter intuitive, the cure for a system that is regularly burning out tweeters is a larger amplifier. If woofers are burning out, then the amplifier is too powerful and the user needs to back off on the bass demands.

If you give me a job: “Please burn out this speaker”, I will pick a generic amplifier in the 50 Watt range and give it an 80+ Watt job. After a few minutes the tweeter will fail. A SONOS amplifier would be my last choice because they are well protected and will not enter clipping mode. If forced to use a SONOS amplifier for this destructive mission, I’d need to use tricks that are not available to regular folk.

Bottom line: don’t worry about the power ratings for your choices. In most rooms one Watt of average power is very loud, but there can easily be 10x or higher peaks.

If you search the web you can find calculators that work on watts of amplifier power and speaker efficiency that will let you calculate how loud you could drive the speakers in your setup.

buzz is correct. High power amps can blow speakers, but for them to do that you have to be irresponsible with the volume control - as in the case of driving a powerful car on the road. Low powered amps can damage speakers even without your realising what is happening. To bend the car analogy a little, just as an underpowered car can get you in serious trouble if it does not have power to quickly complete an overtaking action.

Many thanks for the responses, which address my question.  In my context, this is for a home set-up playing background music almost always at very modest levels.  I believe there is also a max volume setting on the Sonos which I can set accordingly.