It depends on how high you have the burner, and how many burners are lit. From what I've experienced is about 2-3 weeks at best using it for about 30-40 minutes at a time 2-3 times a week. But this can be different for you. Just a tip from one grilled to another, always keep a 2nd tank on hand just in case.
1 gallon of Propane ~= 4.23 lbs ~= 91500 Btus 1 lbs of Propane ~=22000 Btus 20 lb tank of propane holds approx 4 gallons of propane (366000 BTUs) Your grill will last 366000 BTUs/ Grill BTU output hrs
Theres about 430,000 btu's in a 20 lb propane tank. it your grill is 43,000 btu's it would last 20 uses.
That depends on the output level of the propane.
A 20 pound propane tank holds 4.1 gallons of LP which equates to about 0.016 cubic meters. If your heater burns 3 m3 per hour the tank will last about 19 seconds. If you meant .0003 then it will last 51.73 hours.
To figure this out, check the specifications for your grill. It should report the output of each burner in BTU (British Thermal Units) or kWh (kilowatt hours). One pound of propane contains 21500 BTU (around 6.3 kWh). An average grill might have burners with individual output of around 30000 BTU at full output. Therefore 1 lb of propane will, in theory, last for around (21500 / 30000) * 60 = around 43 minutes. The real time is probably somewhat less than this. If you run it at half output (good for a few sausages) it should last somewhat more than an hour.
It depends on the rate of consumption for the individual grill. Size of burners, number of burners, heat of flame required, manufacturer ... it's like asking how many days will a box of cornflakes last until it's eaten. Too many variables.
Surely it depends on your rate of usage-what appliances you run from it
I believe portable barbecue grills last as long as the propane tank you have, possibly buy a few extra of them, just to make sure they last through the whole entire football game.
C3H8 + 5O2 -> 3CO2 + 4H2O With combustion reaction such as this always balance oxygen last.
The length of time a propane tank lasts on a hot air balloon depends on several factors. These factors include the size of the tank, the operator's discretion, and wind. Most last several hours.
The propane will last until the tank is empty.
If you are looking at the best, you will be spending a very large (well over $5k) amount of money. Also, you haven't specified if you are looking for charcoal, propane or natural gas fueled grills. Last, what options are you looking for? Without this information, the right grill can't be determined.