'Decent' panels come in a range of outputs. Not AFAIK, but IDK.
That means nothing in terms of whether or not it's possible to have a 'decent' installation with 21 panels outputting less than 4kWp.
If you're posting on a subject that comes under AFAIK, then I suggest you don't bother.
So which ones are 190W?
Efficiency is when I replaced the roof and windows in my flat and the tenants could keep the place warm by turning off the heating and breathing.
JGH
Isn't turning off the breathing a step too far... ?
It's lifestyle management to reduce condensation.
Owain
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.