Understanding Your Hot Water Process – How Do Gas Water Heaters Work?

Just like most other residential conveniences, people truly appreciate the importance of running hot water only when it actually stops. The situation can be even worse – stopping while you’re all soaped up in the shower. Luckily, this is not such a common issue anymore. Water heaters these days are reliable and built with professional standards in mind. However, when unexpected situations arise, it’s good to have some background on these appliances. You’re less likely to know how to fix the issue, but knowing what the problem might be help you when the plumber arrives. So, how do gas water heaters work?

Understanding the Water Heating Process

Most gas water heaters consist pretty much of the same general parts, yet each product has its own special features, bells and whistles. The heat exchanger is a common part though, as it represents the main component in the heating process. A gas burner applies plenty of heat to it. When water passes through it, heat is transferred to the water. It absorbs heat from the heat exchanger walls.

For extra efficiency, the watercourse is usually shaped like a serpentine. A straight course will expose the water to heat for just a few seconds – not enough to give you hot water. When designed like a serpentine, water spends a lot more time in the exchanger and absorbs more heat.

Different gas water heaters come with different levels of energy efficiency. The most efficient ones may have an extra heat exchanger. It’s not as powerful as the primary one, as it usually relies on burner exhaust gases. It’s usually used to pre-heat the water in the attempt to use every bit of energy and reduce waste.

Efficient water heaters with two different heat exchangers are often known as condensing heaters. They guarantee for a continuous flow of hot water and they add to your convenience, not to mention reducing energy bills.

Nothing is perfect and condensing heaters make no exception either. While their energy efficiency is flawless, they do cost more than regular heaters. Fortunately, they tend to pay for themselves with the energy savings.

Other than that, it’s worth noting that even models without a secondary exchanger are often rated maximum stars in terms of efficiency.

Keeping the Temperature under Control

Pretty much every gas water heater comes with a maximum temperature. This temperature is pre-set by the manufacturer in the attempt to prevent problems and overheating. Overheating the heater may also lead to scalding, not to mention damaging the item.

While there are no general rules in terms of temperature, many manufacturers stick to 50 degrees Celsius. It’s an unwritten standards that more and more companies adopt.

Regulating temperature is done through a burner. The computer operating the heater will decide on the optimal amount of gas needed in the burner. Incoming water often has varying temperatures, as well as a different flow rate. The amount of gas needed to heat it up varies widely.

That’s what the computer does. It measures the water temperature and decides how much gas is needed for maximum efficiency. This kind of flexibility is the answer to a steady temperature. You’ve probably noticed that water temperature doesn’t change as you shower, but stays constant. What changes is the amount of gas needed to keep it that way. Measuring the temperature is pretty simple. Most heaters come with small sensors on the exit pipe of the exchanger.

In the attempt to let customers gain flexibility and full control, more and more manufacturers implement temperature controls. Practically, the user can bypass the pre-set factory temperature and decide on what’s better for them.

Temperature controls are often available through a small screen on the actual unit. They are wired to a specific location, such as the bathroom or kitchen. Smarter appliances come with wireless control. Every update in the temperature will reflect over the computer, which will then update the gas flow and burner.

Considering the Power Supply

Power is mandatory in running a gas water heater. Most appliances rely on a sparking igniter in order to light the gas up. They’re mostly designed for residential properties and not outdoor or camping locations. Therefore, they’re usually connected to the main power supply of the home.

Recent years have brought in a few innovative models that can even reduce your electricity bills. They feature small water turbines which the water has to go through before coming out. They practically generate their own energy and can run for specific amounts of time without using any electricity at all.

Battery operated water heaters are not so common though. You can find some in commerce, but at the end of the day, they’re useless unless you need them outdoors. Whether you want the heater in your backyard or on a camping trip, batteries become a viable option.

Battery and turbine models come with one major advantage over traditional models – they work even if you have a power outage, as well as remote areas that may not have too many modern facilities.

On a negative note, turbine water heaters also come with some drawbacks. For instance, they’re much larger than traditional models. Besides, given the savings in your energy bills, they’ll cost you more to purchase.

How Gas Water Heaters Work – Brief Summary

  • The gas water heater has two incoming pipes – gas and cold water. It needs cold water to heat it up before releasing it, as well as gas supply to heat the exchanger and transfer the heat to water.
  • Based on features, the water heater has multiple sensors to detect the cold water temperature and figure how much gas it needs to reach the desired temperature.
  • Water goes through a heat exchanger. It absorbs heat from the walls and goes to the outgoing pipe. It’s then transferred to wherever you need hot water – kitchen tap or shower.


Simply put, knowing how a gas water heater works will help you determine whether or not this is the right model for you when changing or upgrading your previous heater. There are, indeed, more types of water heaters out there. The gas operated model is traditional.


More Reading

Post navigation

Leave a Comment

Leave a Reply

Your email address will not be published. Required fields are marked *