Instant water heater for 9000 ft. elevation

Hi,

I'm looking for a quality propane instant water heater that will work at 9000 ft. altitute. I'm hoping to use 1 for both radiant heat and hot water, but am open to 2 units if that is a better option overall. The house size is aprox. 2400 sq ft. with PEX infloor radiant heat and 2.5 baths, super insulated.

I've been researching, but most heaters seem to be not recommended for over 5000 ft.

Any help would be appreciated!
Thanks,
Dan

Rinnai claims their units can work up to 10,000 feet.

I do not think however that they are recommended for home heating, just water. You may void the warranty in this application.

super!

Thanks! That was just what I was looking for!

It would pay to talk to your local gas company, if you are talking NG. In Colorado, for example, the gas company derates the gas, so many devices work at altitudes beyond their nameplate rating. Other states do not do that. Sometimes, there is a high altitude conversion kit for your appliance.
In any event, the BTU rating is affected.

Bottom line, there are a lot of little details to check out, and in general this is why you find a lot of electric at higher altitudes.

I am using propane. It didn't occur to me until recently that altitude would be an issue... just something I discovered while researching which heater to buy.

Just like normally aspirated cars and trucks (an people, too!) don't work as well at altitude, things that burn have problems as well. The air really is thinner so setting the thing up for a proper fuel/air ratio is different. You'd likely have to install a smaller orifice because it wouldn't be able to supply enough volume or air as at closer to sea level (which includes the oxygen required to burn the fuel) since it is much less dense.

You'll need to recalibrate all of your baking and cooking (at least things that might be steamed or boiled) times as well since water will boil at a lower temperature - it takes longer to cook things (unless you use a pressure cooker). Your bread might rise higher, though.

I bet George Gobel could make it work just fine...