How Important are BTU’s When Buying a Gas Grill?

John McCloySeptember 20, 2020August 3, 2022

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Grill manufacturers love to harp on about how many BTUs their grills have.

But what are BTU’s? And are more BTU’s always better?

To clear things up, we’ll break down how grill temperatures actually work and whether a grill’s BTU output is worth paying attention to.

What is a BTU?

BTU stands for British Thermal Units, and one BTU is the exact amount of energy needed to heat one pound of water by one degree Fahrenheit.

You’ll come across the term on lots of different household appliances including air conditioners and heaters but for the purpose of this article, BTU are used to measure the output of each burner on a gas grill.

Why you shouldn’t focus on BTU’s

The most important thing you need to know about BTU’s is that they are not an accurate way of measuring how hot a gas grill gets.

BTUs, or BTUs per hour to be more accurate, only measure how much fuel a grill’s burner uses over an hour. The calculation also takes into account gas pressure, the aperture of the gas valve, and the type of gas being used as fuel.

“A grill with a high BTU rating will use more fuel than one with a lower rating.”

How important are BTU’s – Weber

Think of it like miles to the gallon when it comes to a car. Just because the vehicle in question uses more fuel per hour doesn’t mean it drives any faster. In fact, you might get more speed from a more fuel-efficient engine.

Gas grill manufacturers like Weber are quick to point out that, although some of their models have lower BTU ratings, this is because they are more fuel-efficient, not because they have a lower heat output.

BTU ratings on grills are specifically related to the maximum output of the main set of burners. Most reputable grill manufacturers will stick to that convention. 

Still, it’s not uncommon for less scrupulous manufacturers to add in the BTUs of side grills, or accessories like rotisseries, to try and bump the overall number up.

So how do I work out a grill’s heat output?

While most manufacturers list their grill’s BTU output, there’s a better way to work out how much heat a grill can generate.

Over at amazingribs.com they recommend using “heat flux” in order to figure out how hot it can get. 

Working out a grill’s heat flux is actually fairly simple. You divide the stated BTUs by the square inches of the grill’s primary cooking surface. The higher the number you end up with, the more heat is transferred from the burners to the grill surface.

Even then, this is a ‘best-guess’ kind of situation. It doesn’t take into account environmental factors, the distance between the burners and the cooking surface, or whether the grill is infrared or standard convection. 

How important are BTU’s when buying a gas grill?

So, are BTUs significant, and is it worth figuring out and comparing the heat flux of competing grills?

Well, the reality is, they aren’t. Not anymore at least. 

The construction methods for gas grills have advanced in leaps and bounds over the last decade. Modern grills have become much more fuel-efficient, degrading the importance of BTU’s as a measurement of quality. 

Additionally, different heating methods, like infrared burners, have furthered muddied the waters, making it even harder to translate BTUs into a usable idea of how hot a grill gets.

So, if you’re looking to buy a gas grill and BTUs aren’t a particularly good metric for quality, what should you be looking for?

Build quality is always of paramount importance when it comes to getting a good gas grill. Well made heavy-duty components and a well-fitting lid will arguably do more to heat up a grill than an arbitrary measurement of how much fuel it uses.

If you still want to include BTUs into your calculation, then as long as the components are well made and fit together tightly, a heat flux range of between 80 to 100 means the grill you’re looking at will heat up quickly and maintain a consistent cooking temperature.

If you’re purchasing an infrared grill, then you can settle for heat flux ratings in the 60 to 80 range because infrared grills tend to be more fuel-efficient than convection grills.

Higher isn’t always better

On the surface, a grill offering a very high BTU output might seem like it will heat up faster and maintain a more consistent cooking temperature. However, the opposite is often true.

Very high BTU output is often a sign of a poorly constructed grill whose design and manufacture is fuel-inefficient. The wasted heat lost through badly fitted parts or thin lids means the grill needs to draw more fuel to heat up. 

Since BTUs measure fuel used per hour, these grills can often offer seemingly impressive heat output but, in reality, have disappointingly poor performance.

Wrapping it all up  

BTUs are a somewhat outdated and not particularly accurate way of measuring the heat output of a grill. 

Heat flux outputs of 80 to 100 for convection and 60 to 80 infrared are normally a good indication that a grill will heat quickly and maintain temperature. However, BTUs are too often presented in a confusing, or downright misleading manner, making it hard to get an accurate idea of how good the grill in question is.

When it comes to buying a grill, well-made components, a good design, and good manufacturing techniques are usually more important than an arbitrary BTU value.

Do you pay much attention to BTU values when buying a grill? We’d love to hear your literal ‘hot take’ in the comments below.