Is HVAC efficiency landlord's responsibility in CA? Thoughts?

[Jeni Nikolova]

Good morning!

Our tenants have asked us to get HVAC service, as according to them the system is not as efficient.

For context: this is a single family home we are renting out in CA while living in a different state.

We did spend almost $10k this year to get pine trees cut down in the backyard, for fire prevention, which is not a cost we had accounted for when determining the monthly rent.

We did change the motor of the AC in 2019, and from what I understand AC maintenance is not responsibility of the landlord.

The previous tenants, did get HVAC service themselves.

What would be a polite and tactful way of getting back to the tenants' ask for HVAC maintenance?

Thanks