The code requires you to have hardwired smokes in all the called out locations (outside bedrooms and within each one). The code requires both AC power and the smokes to be interconnected to each other. You need to replace it with the same one (or a compatible model), or update them all.

I do not believe the above is correct - unless you are selling or buying.

If you Google it there is a ton of info on CA Smoke Detector Requirements

I don't know CA code, but I think it depends on what the code requirements were when the house was built. However, CA may have specific laws that require retrofitting older homes.

In any case, hardwired smoke detectors are (IME) superior to battery operated ones. If it were my house, I'd replace it with a good quality new hardwired smoke detector.

In MD by Law Battery Powered Detectors now must have the ten year batteries -

I do not believe the above is correct - unless you are selling or buying.

Eh? The building code is not affected by whether you are selling or buying. Yes, you can get away with violating the code if you've got a single-family house that you're currently residing in, but that doesn't make it a good idea to do. He asked if there was a regulation, and I answered THAT question.

No need to throw a hissy fit. Indeed Smoke Detector requirements can be dependent on selling or buying a residence.

I was polite in posting, don't know why you're having a fit???

But one example, of many, many:

"One legal requirement when selling a home in Massachusetts, and in some other states, is that you must have installed smoke and carbon monoxide detectors prior to closing.

Otherwise the closing will not be completed. If you are planning on selling your home, it is important that you meet the smoke detector and carbon monoxide detector requirements for your area prior to closing to avoid unnecessary delays."

Thanks everyone. I googled, and found that CA does not mandate hardwired smoke detector, but if it's battery powered, it needs to be 10-year battery.

So I'll just get hardwired detector. How easy is to change electrical smoke detector? Do I need any tools?

Massachusetts is entirely irrelevant to California.

I was unclear in my statement (and others corrected me). There are indeed modern battery operated units that comply with the California code. And yes, if your house is old enough there's no need to bring it up to current code (provided you disclose the deficiency if you're selling), but it sounded like the poster wanted to regress from the a later code-compliant installation which isn't permitted.

The separate issue (which I was alluding to) was the interconnection requirement. If interconnected smokes were required (including any retrofits), then you need to maintain that requirement. This means either using a compatible hardwired smoke or replacing them all with ones that boogie with each other wirelessly.

It appears as if there are three issues here: smoke detector requirements in general; hard-wired smoke detectors; and hard-wired, interconnected smoke detectors. It's easy to comply with the first, especially if you used 10-year battery-powered ones. Hard-wired are a little more difficult, since you have to run a 110 volt circuit to each detector, and the interconnected ones where not only do you have to run a 110 volt circuit to each detector, you have to run wires between them.

The California requirements, like most other states, are in general detemined by when the house was built. I quoted MA simply because it was the first Google hit.

The OP lives in a home built in 1976.

There are some exceptions to the general rule... my 1973 Home in Montgomery County, MD, of course originally had no Smoke Detectors. As a matter of common sense, I had installed battery powered detectors years ago. The County now required that they all be replaced with the Ten Year Battery types, and I complied.

Your statement of " The building code is not affected by whether you are selling or buying" is absolutely wrong.

Again. all I said re your post was, " I do not believe the above is correct - unless you are selling or buying." I don't get why you seem to feel that it always necessary to launch a personal attack and frequently include info that is not applicable to the OP's location!

There's no "personal attack." You posted stuff in response to something that I said that was entirely incorrect and irrelevant and all I did was point that out,