Heating elements are one of the most important elements of an espresso machine. Since consistent water temps is one of the key ingredients for a perfect shot of espresso it makes sense that we spend a lot of time thinking about this subject! Today we’re going to talk about the differences between heat exchanger and dual boiler machines so that you can make a more informed decision when it comes time to pick your next espresso upgrade!

Heat Exchangers

If you aren’t familiar, a heat exchanger system like what's in the Diletta Bello+ uses a single boiler that will typically be about two thirds of the way full of hot water, and then a third of the way full of steam. When you flip on the pump, water passes through a small tube in the boiler that gradually heats it to the proper brewing temperature. These systems are typically carefully calibrated to hit desired brew temps, and the steam contents in the boiler mean that as you brew you can easily froth milk simultaneously. 

These systems are great for those who like to drink lattes and cappuccinos, and are a little more user friendly due to the way they’re calibrated. There aren’t really downsides to these types of machines per-say, but they are interesting when compared with a dual boiler machine.

Dual Boilers

Dual boiler espresso machines, such as the Diletta Alto are what they sound like - machines that have separate boilers for steam and for brewing. Typically, the temperature of each boiler can be adjusted, which can give you finer control over your brewing temps than you can get with a heat exchanger. It also means that when at capacity there is a full boiler for both your steam and your brewing water. In theory this can allow you to brew more drinks in a row than you might be able to on a heat exchanger, as the total volume of hot water/steam is going to be higher.

There are, however, a few key things to keep in mind when you’re deciding between a heat exchanger or dual boiler espresso machine. These can mostly be divided into power requirements and machine quality.

Comparison

The first thing to consider is the power requirements of your new espresso machine. Most outlets in the United States provide 110 volts of power. This is enough for a machine to function, but dual boilers won’t be able to draw enough power to recover temperature in both boilers at the same time. Instead, as the machine draws water from the tank and comes up to temp, it’ll prioritize the brew boiler. This doesn’t mean that it can’t then maintain that temperature and heat more water for steaming, it just won’t be able to do both at the same time in most conditions. Alternatively, a heat exchanger uses one heating element instead of two. Because of this, you’ll actually see faster recovery time on most US power circuits. The math is a bit fuzzy and hard to guarantee here, as you may find that a heat exchanger machine needs to recover before a dual boiler would due to capacity, but that recovery should, in theory, be faster.

Then there’s fit and finish. It stands to reason that dual boiler machines are, in general, simply more expensive than a heat exchanger. This is because dual boilers have, well, two boilers inside. This means that if you’re shopping at a specific price point you will likely be able to get more bang for your buck out of a heat exchanger machine. It will likely be a bit sturdier and built with higher quality components than an equally priced dual boiler machine.

This is, of course, not always the case, and you should do research on the specific machines you’re shopping for to be sure.

In any case, both types of machines are a solid purchase. A heat exchanger may provide more value and better performance over multiplier drinks, but a dual boiler can give you more precise temperature control over both heating elements. Which piece of the puzzle matters more for you is up to you to decide! For more information you can check out our video on the subject below.