There are a few technologies for hammer drills. Generally you have a selector button on the side if you want just drilling or also with hammer function, or in some cases just hammer (bit doesn't rotate, useful for chisel-like bits).

One simpler technology does the hammering through a couple discs with a Z profile - the rotation of the motor plus your force of pushing the drill towards the wall gives the bit some light hits. These make a lot of noise and not too much progress in hard concrete, and your arms will go numb. I don't think I have ever seen one advertise the impact force or, if it did, it was rarely above 1J (Joule).

Then there's the other kind, which generates the impact force either mechanically or pneumatically. They are generally bulkier and seem to have a secondary motor perpendicular to the drilling axis. These go easily into 2,5-3J. They are not so loud, but VERY efficient. Just be careful at first, the drill will feel like it's pushing you back a few inches ehen it reaches the concrete layer, hold steady so that you don't break it. The SDS mandrel helps (instead of the classical drill bits).

Borrow or rent one for a few holes. If you need one more frequently or want to own one, look for Lidl's promotional periods when theybput on sale their Parktool model, it is excellent for its price without breaking after the 5th use.