Difference Between Condensing and Non-Condensing Tankless Heaters

The traditional water heaters all had a storage tank where hot water was kept and sent through pipelines to users’ showers and taps alike. But in recent years, tankless water heaters have become quite popular and this change in norms is due to a good reason. Tankless heaters are extremely efficient and they also have energy saving features, which is great for users. In the previous models of heaters, a lot of energy had to be used to reheat the water on constant basis but with this new model of water heaters, hot water can be created on demand saving precious energy.

condensing vs non condensing tankless

The process is simple enough as the water moving through the pipes gets heated and people use it as per their needs. As for the most common types of tankless heaters, there are two: condensing and non-condensing heaters. If you are looking into buying one, you need to learn about the differences between the two.

Condensing Tankless Heater

When you first switch on the heater and get ready to use hot water, you wouldn’t be able to see the underlying process behind your hot water supply. These water heaters use combustion and a gas burner to create exhaust gasses within the heater. The exhaust gasses are vented into the unit and allow for extra heat to be created within it. By using these gasses the water heater can easily heat up water.

The condensing heater has two heat exchangers, and before any water goes into the main heat exchanger it is already warmed up. The second heat exchanger reuses the exhaust gases being produced to heat up the water and bring the temperature up using warm gasses.

Due to these exhaust gasses being used and heat being extracted from them, vapor or steam forms in the unit and as the steam cools down it turns into condensation. Exhaust gases are warm enough but they are not extremely hot at a temperature of around 100 F. In comparison to the gases used in non-condensing heaters, this is almost a mild temperature which is why the ventilation system used in these heaters are not expensive.

The low cost of ventilation is compensated by the possibility of corrosion due to condensation. This is why condensing water heaters must always use materials such as stainless steel alloys that prevent corrosion.

Non-Condensing Heaters

While condensing vent exhaust gasses inside the unit, the non-condensing vent exhaust gasses outside the unit and they do it immediately after heating up the water. The water heaters heats water using a gas burner and right afterwards the gasses are vented outside which makes it a little bit inefficient. The heater loses about 20% of the heat through ventilation alone that could be used to make the water hotter.

Due to the extra hotness, the heater reaches temperatures of about 300 F and venting materials being used must be able to withstand such heat. This means that the typical PVC vents that are so popular with condensing tankless heater are of little use and the cost of installation for a venting unit is high.

Condensing Vs Non-Condensing: Which Heater Wins?

There are some pros and cons for both the types and for each one of them you must be ready to make some tradeoff. The fact remains, there are two types of heaters because they are equally as popular and depending on the user equally as useful.

When we talk about effectiveness of heating up water supply, the condensing wins because of its inner structure and energy saving features as opposed to non-condensing types. But in some instances when the surrounding temperature or air temperature isn’t suitable their effectiveness may be limited. By comparison, the effectiveness of non-condensing heater comes at a cost. The additional expense of venting units makes it slightly less appealing if you are looking to cut back on costs.

When we talk about purchase costs non-condensing types are less expensive but the overall expenditure of venting units is higher for them while condensing types are cheaper to buy and also have a 10 to 15 percent more efficient operation.

Condensing types, however, have a higher annual maintenance cost as they require continuous maintenance and their viability depends on the type of water being heated up that non-condensing types do not have to worry about. On the other hand non-condensing tankless water heaters are a bit smaller in size and require an indoor combustion air.

What Else Should You Consider Before Buying?

There are two basic and extremely important factors that you must ponder over before buying any home equipment including your water heater: the first is whether the equipment will help you save energy and subsequently costs, and secondly will the energy saving still allow you make the most optimal use of its functionality.

You cannot compromise on any of these fronts and that is why it is important to consider buying a tankless heater over a traditional water heater. The initial investment might be twice or thrice as much but over the course of months and years, the savings on your monthly bills and the luxury of a steamy hot shower will make up for the excess costs.

The other important things to consider are your budget and safety of your house. It is best practices to invite a professional into your home and have him look at your residence to guide you through the changes, fixtures and upgrades necessary to install the equipment. A professional opinion and your own judgement about the brand, the size and other features of the water heater are vital to you making a good decision. The best choice is one that sits well with your budget, gives you the satisfaction of smooth operations and provides safety, services, cost-efficiency and energy saving all at the same time.