I stayed in this very nice house for a couple of months.
It's located in a very convenient position to reach Caltech and not far from Old Pasadena (40 min walking, better by bus or car). Very quiet and friendly neighborhood. The closest metro stop to get to downtown LA is less than 15 min walking.
The house is organized with a large shared space on ground floor and the bedrooms (5 in total) at upper floors.
The kitchen is complete with all appliances, the open space on the ground floor also includes a big dining table, a couch and a TV. The washing machine and dryer are in the private garage, which has 2 spots for cars.
The air conditioning works perfectly and this is important with the temperatures that can be found in this area in the summer. It's preset for the whole house to a comfortable temperature .
My room was nice and tidy, with a private bathroom, a small desk and a big window opening to a balcony (shared with next bedroom). The only minor drawbacks were that the room was not very spacious, there was carpet (which I dislike because it is difficult to clean) and the garage door, directly under my room), is quite noisy. Apart from that it was a very pleasant stay!
The accommodation is not cheap but it's in line with the crazy prices of California, as I learned directly from my time in the US.
The host is responsive and always available for your needs.
I would definitely stay here again!