In that case I would purchase four window style air conditioner/heaters to mount into two of the windows per unit.That means each apartment will have two units they can control and this will be more than enough to heat and cool 1000 sf or less providing you purchase them to accomadate the correct square footage.The pros and cons of going this route:Pros:Cost.

Add a few window air conditioners you don’t have enough power.  

For cooling, we rely on seven window unit air conditioners and free-standing window units. 

(short tangent below)I recently had a house that had a window air conditioner in the wall to cool the dining room. 

I can furnish a 2 bedroom for $3.5k (including labor) and a 1 bedroom for $2.5k including labor.Some units have more amenities than others depending on the building but we offer soap, conditioner, razors, ect.

It is in the lease that they must maintain it, but my guess is they can't figure out how to work the timer... they also have air conditioners in the windows which is not allowed by the HOA.Still wondering why I find this out from neighbors instead of the property manager... but I guess I'm not enforcing better behavior. 

Fully furnished and renovated including new roof, recent F/A furnace, window air conditioner.

Wall space heaters and window air conditioners in some of the older houses. 

We have experienced this over and over where the owners are spending money on deductibles and then we have to send out our maintenance people to fix the problem.Our next problem came in the form of a malfunctioning air conditioner.

Shhhhhhhhh A little secrete from an old timer.........From a bag of water conditioner salt rock place some on top of the soil or within a trench and back fill with earth or pack salt rock granules into 1/2 inch round holes drilled 6" apart through concrete 4" away from foundation footings along area of noted termites entering structure, plug drilled holes afterwords.