is it the landlord's responsibility or ours we rent our house and the air conditioner is not working at all. it is very hot so hot that due to being hot we lost our cats

Well, it should be the landords responsablity. However, a/c is usually considered a bonus, not a necessity like heat in the winter would be. Take a close look at your contract or merely just have a chat with the landlord and see what they say. If the a/c worked when you moved in, he should get it up and going again, just depends on what kind of landlord you have. Good luck.

it depends on whether ac is included in the rent.

If you rented a home with AC and nothing was written about you being responsible for repairs then the LL needs to fix it whetehr it is written in the lease or not.

So , have you notified them, both by calling and in writing ?

How long ago, what did they say ?

Window unit or central unit.