Hi Jan
We've stayed in a few, from very good to pretty awful. The last two apartments we've stayed in have been very good, albeit quite different. Neither have views, though the relatively high rise nature of Torino does make this more of a rarity (we have seen some advertised though). Both are on upper floors, and both had a lift.
Casa Diaz on the eastern end of Via Maria Vittoria (a stone's throw from the River Po) is a private apartment, where the owner used to live before moving in with their partner. Cosy, and has a nice lived in feel. Kitchen and bathroom perhaps a little dated, but clean, functional and everything works (including the washing machine). Bedroom is very nice. Generally quiet from being in the usual internal courtyard, though of a weekend there is a little noise from a local bar, but it's not raucous. A short walk to Piazza vittorio veneto, and via Po, but not far to any of the centre, plus close enough to the Po to encourage a trip over to the Gran Madre church (Italian job wedding scene) and other chilled places over the river. Overall a great place if you want to feel you are living like a local. Not sure if there was AC, but it was certainly comfortable when we were there and the internal courtyard with patio windows would allow for very quick cooling outside of peak summer - definitely fine for May
Loger Confort (yes that's the spelling) is more of a aparthotel / Residence, with a bright and classy apartment, fitted well for such places. Staff on site on a lower floor to help, advise, chat to, though as it was ~ our 10th visit to Torino, my questions were limited to where was good for aperitivo at the time! They were friendly though. Location is very good indeed, on the southern end of via XX Settembre, 5 mins walk from Stazione Porta Nuova and very handy for trams/buses going north and not inconvenient for those going south (they stop a block to the west), east or west (both on via Vittorio Emanuele II. Also handy for the Metro line which we used more than we have in the past (I happen to like the trams!). I think there was aircon, but as is often in Italy, I'm not sure it was on in March.
In the past we've also enjoyed
Residence du Parc (via Madama Cristina?), but we've found their prices too high in recent years. Worth a look, though it is a fair walk to the centre, but on the flip side very convenient for Parco Valentino. The apartments are very spacious, albeit remarkably spartan. Like Loger Confort there is daily cleaning if wanted, but I find such things unnecessary for a week's stay and we'll always make sure it's clean/tidy when we leave anyway.
May is often a lovely time to go, but we did hit a heatwave then one year with temperatures above 30C. I really enjoy the fruit available then, especially Nespole and the tiny alpine strawberries (Fragoline). Top discovery from our last trip was a greengrocers who seemed to have sought out the best examples going. I've never tasted Kiwi fruit anything like the ones they had - truly zingy, but everything impressed. I can throw plenty of other suggestions in depending on what you're looking to buy to eat at the apartment. Torino is a fantastic grazing city, on a par with Bologna IMO. going
https://www.google.co.uk/maps/place...x2bb991259f938245!8m2!3d45.068076!4d7.6675592
Hope this helps
Ian