| Don't go spending hundreds and hundreds of dollars on lighting unless you're growing in your basement or a converted closet.
boxer, your south-west window might do fine but there's no way to tell because I don't know what kind of plants you're growing or what kind of light yu get inyoru window. Is there a sheer? How many hours of direct sun in the window? Typically a south-west window would be good for high light plants. If you are growing medium to low light plants, you'll need a sheer or something to cut the intensity.
In the US, south windows are usually high-light environments, but the light can be direct and burn and south windows can be hot too and so not good for cool and some intermediate growing orchids; east and west windows are usually medium-to-high areas with east windows usually cooler than west windows because they haven't had the day to heat up so I wouldn't put a cool-intermediate orchid in a west window; and north windows are usually low light.
You can see the different components of orchid environment are interdependent. While higher in light, south windows are usually also higher in heat and lower in humidity. East windows, especially if they open can offer some nice morning humidity. North windows, along with being low light can also be cooler.
__________________  |