Starting to see quite a few questions about the BHMA lock standards as more inexpensive matter locks are coming out.
There are a lot of different technical specifications, but overall it’s pretty simple.
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grade 1: Commercial. For example, these locks will withstand at least 10 ramming attack blows. Expect to see lots of metal parts instead of plastic and typically steel at the stress points instead of aluminum. Also more interior locking bolts or double connectors to keep the lock from breaking loose when under physical attack
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Grade 2. Residential and light commercial. For example, these will withstand at least five ramming blows. More metal interior parts, although they may be aluminum. Higher quality brands like Yale will include interior locking bolts and some double connectors. I believe all Yale Smart locks are level two and most Schlage smart locks are. Most public schools use grade 2 locks.
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light residential. These will withstand two ramming attack blows. Typically, they use a lot of plastic and don’t use interior locking bolts or double connectors, all to save cost. These are almost all budget brands. A number of Kwikset locks are at this grade. And the new Aqara U50, for example, is grade 3.
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Grade 3 doesn’t mean it’s a bad lock. It does mean it’s a lock that’s designed to be inexpensive, typically with more plastic interior pieces, and is not likely to hold up to any kind of significant physical attack even just with a hammer.
Do you care? That just depends on your situation. If the lock is more as a deterrent for neighborhood kids and the kind of burglar who will give up as soon as they encounter much of any problem, many people will consider it sufficient. And of course, the more additional security devices you use, like cameras, lights, and sirens, the less the lock itself needs to be the defender.
If this is for a vacation cabin in a remote location with no close neighbors, you might need a much more secure lock. (And if you have to worry about bears, personally I would definitely go for grade 2.)
It’s probably not worth the cost to pay the difference between grade one and grade 2 for your typical suburban home. Because a determined thief can usually just break a window and get in. Grade one is more for a situation where you’ve also secured windows and you’re concerned about a determined thief with a crowbar.
So: Choice is good. Different things will work for different people and different situations, sometimes even for different doors on the same house. I’m happy to see the new lower priced matter locks coming out, And some of them have some very nice features. And now you know the difference between BHMA grade 2 and grade 3, in case you want to factor that in. 