They can use portable ceramic heaters to take with them house to house.  

The downstairs is cement slab... is ceramic tile too heavy to put in the upstairs units (this is a rental)?

For example, we had one Humanities and Social Sciences", but also had a building for Ceramic Engineering.

The building was rehabbed two years ago including: new torch down roof, waste lines, water supply lines, HVAC, electric, thermal windows, ceramic tile in all kitchens & baths, int/ext paint, and new fixtures throughout.

$1,200 labor + 275 paint Ceramic Tile the counters & Backsplash $275 labor+$150 MaterialAttic had no insulation.

I do:smaller diameter recessed lights nicer door knobs (not base home depot ones)nicer cabinet hardwareslightly upgraded granite and appliances Pls end marble in master bath instead of normal ceramic solid core interior doors instead of hollow

For ceramic tile, large format is in, 12x24 (which is great because it's cheap and quick to install), subway tile backsplash. 

If they had engineered hardwood put real hardwood, You want to be the best property period.Our rehab we just did-there was a house in our subdivision that did just like we did- granite counter tops, ceramic tile- the house didn't look like ours because we all have diffrent tastes however ours was the best rehab- we got 4 offers in the first week while that house sat on the market for 60+days during the summer.

., new ceramic tile in the hallway, kitchen and bathroom, and bathroom completely redone (new bath and surround, new vanity, new ceramic floor, new toilet) all at a cost of some $10,000.

Renovation wise I would concentrate on the kitchen and the bathrooms tenants love nicer looking up to date kitchens newer knobs and faucets fresh pain and maybe even ceramic tile the floors if that is in your budget.