For simple 4" downlights, consider installing cheap 4" cans, put Cree CR4s in them, and be done with it. No need to buy extra trim, since the trim is integrated with the light.

Thanks for the suggestion, but I have read about the cr4's and I am looking to keep the look of the smaller mr16/gu10 bulbs. Also, with the price of leds set to plummet in the next few years, I think you will be able to purchase cheaper and brighter bulbs very soon.

That said, is there any benefit with going with the low voltage setup versus line voltage? What would you be getting for the extra cost now?

MR16 LED bulbs from either HomeDepot or Lowes today do not match 50W halogen MR16s.

You will have to wait for the sales channel to drain existing stocks.

If you want high output and small MR16 like lamps, CSL Lighting has such available at more than 2x the price of a CR4 (ECO4-575) + housing.

Such lights are low voltage with an integrated power supply in the can. Although they are directly connected to the 120V line voltage supply, the integrated power supply supplies a low voltage output to the LED.

Benefits -
1. 2" aperture can be achieved.
2. Can be retrofitted - the ceiling board actually holds up the entire assembly.

While you can achieve a 2" aperture, the hole is typically much larger and is covered by the trim.

Typically, the smaller the can, the higher the price.

The csl lights look nice, but I am sure they are quite pricey. My plan isn't to put the led in yet, but to wait for the products to appear on the market and the price to drop. I think I would want' to switch when there are real 50W replacements.

Mostly I am looking to figure out what infrastructure to support the best bulbs down the road.

I am looking at putting in the HALO 3" housings with the square trim. These take GU10 bulbs, but I am also looking at alternatives such as ELCO for low voltage.

It seems the best value is to put in the line voltage now and then swap the bulbs later. I just don't know if I am giving up anything by doing that.

I mentioned in my earlier post that the CSL lights cost > 2x that for the CREE CR4 + housing. i.e. - ~ $166 vs The most prudent thing to do at this stage is to price out each of the possible lighting options - 3" vs 4", low voltage vs line voltage.

I have done my homework which is why I am not interested in putting in the LEDs now. They are way too expensive but all the government regulation and the LPrize will bring the cost down significantly in the next few years. The low voltage housings and dimmers are about 30-40% more in price.

I am trying to stay around 50-75 per light as I have a whole house to do.

So this is not about putting in LED now. It is picking the housings and trim to support future LED bulbs.

So the question is how does low voltage v line voltage impact the ability to put in LED bulbs later?

I am interested in the following
1)availability and price of gu10 led v mr16 led in the future. I heard there are more beam options for mr16
2)dimmer compatibility. Line voltage dimmers work pretty well. I know low voltage dimmers have to be compatible with the housing.
3)Housing transformer compatibility with the bulbs. Will this cause a problem for dimming?

Where are people placing their bets?

We completely rebuilt our house about four years ago, and I went through some of the same thought processes. The technology was moving fast, but LED really wasn't there yet. So I only used CFL/fluorescent where I had to (Cal Title 24...) and a variety of incandescent and halogen everywhere else. If I were doing it over again today, I would go straight to LED everywhere possible and not look back. The little bit extra you might pay will be quickly recouped in energy savings. At least for any lights that are semi-highly used. (Like more than a couple of hours a week.)

The cheap 4" can + CR-4 combo exactly hits your price target today. However since you seem fixated on MR16s, I suspect there will always be more to choose from with the low voltage MR16s, rather than the GU10 versions. Fewer technical issues. And, stepping out on a limb here, probably a bigger market.

"So I only used CFL/fluorescent where I had to (Cal Title 24...) and a variety of incandescent and halogen everywhere else. If I were doing it over again today, I would go straight to LED everywhere possible and not look back. The little bit extra you might pay will be quickly recouped in energy savings. At least for any lights that are semi-highly used. (Like more than a couple of hours a week.)"

Not sure I understand the math here. What are the huge energy savings of LED over CFL? LED lights are more expensive than CFL now and they were considerably more 4 years ago. I think the purchase price recovery time from energy savings will not be as quick as you think it is.

I assure you I can do the math. I was comparing LED to halogen - which is what the OP was asking about.

But since you asked: The CFL cans that we have in our kitchen and a few other places are Juno ICPL626EN. I just looked around the net and found them for about $60/can, plus another $22 for trim, and $5-10 for the 26 watt bulb. That works out to about $90 per location. The bulb is rated at 1800 lumens, But I think due to the bulb and trim design less than half that actually makes it downwards. (Not measured.) They take about a minute, literally, to come to full brightness. Annoying as all get out.

Contrast to a cheap 6" can with a CR-6 at about $50 per location. All 575 lumens pointed down, so no fixture losses. instant on, beautiful 92 CRI light quality, and they dim. And they only draw 9.5 watts each. Do the math. Even if I needed twice as many CR-6 to get the same illumination levels (which I doubt), I'd still be money ahead with LED in the end.

In our MR-16 fixtures (mostly 12v for wall washers, but also a 6-light track light that uses GU10s), CFL really isn't an option. The few I have seen get horrible reviews. It is halogen or LED. Four years ago we used halogen. But because some of these are very highly used, I have replaced most of the 12v ones with the 10 watt Philips LED - which are easily as bright as the 50 watt halogens. At the tier 3 energy rates of about $0.30/kwh payback is less than a year.

What you were comparing was not at all evident in your message.

I just went out and bought 2 occupancy sensor switches.
The Lutron Maestro and the Passr and Seymour.
Both can be used with LED, CFL, and incandescent.
I was looking for the Lutron but the first store didn't have any.
Any preferences?

BTW- love your handle roadbike!