I looked on the Monogram.com website. Not knowing which exact model you want, I had to just pick one to look at, but using the 5-burner ZGU385 just for an example, it says the following:

for Natural gas burners
1 burner @ 18,000 BTUs
2 @ 12,000 BTUs
2 @10,000 BTUs
Total output: 62,000 BTUs

But the LP version offers
1 @ 15,000 BTUs
4 @ 9100 BTUs
Total output: 51,400 BTUs

This seems to happen with brands that convert a natural gas unit to work with LP. Some manufacturers actually build LP units, rather than just converting NG appliances, so that there is no BTU loss. I believe Wolf, BlueStar, and Capital all do that.

We have a new ZGU36L4DSS, Propane (LPG) fueled, 36", 4 burner, griddle GE Monogram Cooktop that specs at 17,000 BTU for each of the 4 burners and 18,000 BTU for the griddle.

The same Cooktop fueled with natural gas (ZGU36N4DSS) specs out to exactly the same numbers according to the info provided on the GE website; unless I am misreading the spec sheet.

I believe they adjust the gas orifice sizing to accommodate the different fuels.

Here is a link that might be useful: GE Monogram cooktop specs (PDF)

As to using our GE Monogram cooktop..........love it so far. Still learning to change from electric coil to gas. It is almost too much power (heat).

I've never before been able to use such a wide range of cooking temps and learning to do so is a blast. I've not yet had more than two burners going at once and the griddle is extremely handly to use for cooking and as a warming surface.

I am also very happy that we installed a 46" Wolf hood liner with a 1500CFM roof mount blower. It is totaly variable from 0 to MAX exhaust and handles the fumes and heat perfectly. YMMV.

Thanks rhome and jimonthebeach. I had looked on the GE Monogram website as well and saw the differing information that you both sited so I was confused as to whether there was BTU loss or not. I had heard that the newer monograms were being made with adjusted gas orifice sizes as the Wolf, Bluestar and Capital are rather than coming with a LP converter kit. I think I'll place a call to GE and find out and then post. Great to hear that you like your Monogram cooktop, Jim. Is it easy to clean and does it simmer well?

I just got off of the phone with GE customer service. They said that Monogram makes a Natural Gas specific model and a Liquid Propane specific model with the exact BTU's for both. However, if you purchase an NG model and use it with LP, you will need a conversion kit and subsequently lose BTU's. GE Profile only comes in NG with conversion kits. Would still like to hear from other Monogram cooktop owners on their cooking experiences and how they like the Monogram product.

I've been in my house for a year now and I have the 6 burner NG cooktop. I love it! It is pretty powerful and I find that I do not need to use the highest setting most times.

My only complaint is that I saute and fry so something is always splattering onto other burners. I find that if I use a splatter screen, I will spend only a few minutes cleaning the cooktop every time I use it. Other than that, the Monogram works like a dream!

Hope this helps.