Figure on $100 - $150 per can. You'd also be subject to title 24.

In a bedroom, Title 24 requires a dimmer for incandescent fixtures. (And a can with a screw in socket counts...) You can get cans with GU24 sockets to avoid the dimmer, but may find you want the dimmer anyway.

The Cree CR6 LED downlight is available in both screw-in and GU24 versions, with the GU24 version being more expensive. With four in each room, it would be less expensive to use a dimmer and get the screw-in versions.

Just say NO to CFLs.

Thanks for the helpful answers.

Today an electrician visited the house and he said it would cost $199 per can for LED lights. He also said that two cans would give enough light. My rooms are about 11' x 11' with 8 ft ceiling. Are there any guidelines for number of cans/100 square feet?

Cost for CR6 ~ 39.99 (CA), can ~ 15.

I would light the space at ~ 20 lumens per sq ft. So for your space 11 * 11 * 20 = 2420 lumens. Assuming a nominal output of 575 lumens per CR6 and dimming, output per can drops to ~ 546 lumens.

If all the light is from the cans , # cans required is 2420 /546 = 5 (4.4 rounded up).

In SF, even if you are remodeling, it might be required that yu get cans for new construction which are fully housed and cost more. Also, if you live in a multi-family building (even a duplex) I am being told the fixtures need to be further enclosed ina custom made plywood box for each one....this gets very expensive..I'd love to hear if anyone knows if there are Ttile 24 cans for new construction, rated for next to insulation that wouldn't need additonal plywood housing, or if these plywood boxes come prefab from anywhere.

Yes, there are Insulation Contact (IC) rated cans. Eg Halo 7ICAT.

What do you mean by "fully housed"?

Your electrician should know what to get.