E=MC2 is the law used in conservation of energy.
A very very tiny amount of matter is apparently becoming energy, so there is no E=MC2 violation.
Mebbe you are thinking COP, as in over unity or as COP greater than 1. But this has been going on for over 10 years now, so that isn't likely what you mean. Right now with his battery backed up SKL electric generator Rossi has an infinite COP within the life span of a charge.
Rossi supposedly has a means of controlling it, regulating it, stopping and starting the reaction in seconds.
He is finally at the point of announcing his first products in
https://days.to/dec9Eegore, you are among the many who will only consider believing it when they actually can see the certification results. And then they will have reservations and doubts ......
With the light and the little generator Rossi has enough to get the ball rolling once he presents the stuff as certified in a verified reliable fashion. Certification on the generator will take most of an extra year if from now the charge is advertised to last for a year.
Something that Rossi needs to prove out in large sampling numbers over lots of time is how long his charges actually do last at a 95% confidence level. He has very limited end of life data (running to end of life showed his early stuff lasts and lasts and lasts well past his early estimates).
I think, just me thinking and spit balling, that his reactors give up structurally at the electrical to plasma contact points long before the charge itself gives up. Since Rossi made the "many contact points" structural improvements nobody really knows how long his reactor charges last now ......
In any case, if he advertises a year he'll have to test for a year plus a year before being certified for a year if that is indeed the time span he is claiming.
If he were smart, he'd claim 6 months so he can get his certification done quicker.
This legalistic dodge will not affect what the reactors really can do.
"Improvements made over time" are to be expected, after all. Sandbagging at the start to get the certification process done quicker can be followed up with additional certifications for longer time periods making up a "doable" approach if done over time.
95% confidence interval testing on a year or two years of advertised life will take bloody forever to do and some huge sampling sizes, but once Rossi is selling the things actively he can collect the data he needs for his longer life span claims.
Next complicator will be the fact the single controller can light (in rotation) multiple reactors with the max number being how many reactors can be maintained within the current SSM span of the reactors in question. Four is an easy do, 10 seems to be a too full house with Rossi holding at only a half hour of SSM due to some sort of BS EU remote shutdown regulations.
It is clear that, post certification and post UL approval, Rossi's stuff can run a small household power-wise (complete with central AC no less). A power wall battery will likely be needed as well, especially if using solar too. An all electric off grid RV would also be an easy do.
https://days.to/dec9