"Never been asked" along with comments not said here (but applicable)
"we've always done it that way"
I'm sorry are we now disputing imaginary comments here?
doesn't mean that this lack of practice is correct for homeowner protection. This is simply a case of homeowners (and some installers) not knowing that this is available and accepted in the insurance industry whether you like it or not.
What is available to homeowners is policy numbers et. al. Certificate holder's are generally corporations or other entities with need. That's what's "accepted" in my neck of the woods".
Lack of homeowner response here - duh I wonder why... ;-)

Perhaps you'll get homeowner response here.

Unfortunately for the homeowner, I'm sure that your pet peave and corresponding threats of walking away will scare off some homeowners from asking about proof of insurance. "Trust me" and your other arguments exactly what unscrupulous installers would say that can't prove they have insurance. What do you think they say? "I don't have insurance but everything will be fine." :-)

Your assertion that this is what the unscrupulous will say is as sensible as the girlfriend who figures you must be cheating because you said you didn't. After all her cheating ex said the same thing.

I hope you're happy with not providing the homeowner with the best insurance advise here.

I have opinions on what is best for a homeowner. they don't agree with yours. in fact on this issue we've yet to find anyone on this forum who agrees with you. But keep looking. must be someone.
Will you be willing to foot their bill if they get scr'wed by an unscrupulous installer?

Ridiculous.

I'm sure you won't answer this along with my other questions regarding cost, time, proof, what installers with no proof say, etc.

I'm not sure what I haven't answered, cost I previously mentioned is ~$10 to $20 after the first couple each year (which are taken by those corporations who need it). Time? inconsequential. Proof? I have policy numbers et al available. You are the one who suggested more is required I don't know that. What cheaters might say? ask them not me.
Sorry your pet peave has colored you judgment here. You typically give good advise, but WOW, are you off base with this one from a homeowner protection standpoint.
 
I'm delighted to hear that you think I generally give good advice here. Is it possible that you might be mistaken on this one. Are you suggesting that the judgement of everyone else that has also told you this isn't customary, is colored by my "pet peave" as well?

I think that will be remembered, to your benefit or detriment (you can guess which.)

Homeowners, do yourself a favor and ask your insurance agent to see what is best for you.

Earlier, even Joe suggesting getting professional advise, however that advise has somewhat been diminished by further posts. 
You should contact your carrier anyway to ensure that your new system is fully covered and to see if there is a discount available to you for an all electric house (if indeed you are all electric.)

It's obvious that we won't answer each others questions.
Far as I know I've answered your questions. Are you admitting that you are purposefully dodging mine?

Joe, are you willing to end this by reiterating that homeowners should get professional insurance advise, to leave a lasting impression with the homeowner,

Sure......folks, don't listen to myself or geome, consult an insurance professional for insurance advice.

as your last comment on the issue?

Hmmm last comment, well no not after another several paragraphs of your suggesting I am unreasonable when you are asking for something your contractor didn't provide you with, no contractor here believes is appropriate and no one so far supports.
Is it possible that you are the one that is being unreasonable? Take a breath....ponder.....