Calgary Plumbing Tips: How the Size of the Tankless Water Heaters Affects Performance

tankless hot water heater

How the Size of the Tankless Water Heaters Affects Performance

Hi, it’s Kyle from Clearview Plumbing and Heating.  I was washing some dishes the other day and realized that we take hot water for granted.  It also made me think about how to size a tankless hot water heater.

Tankless water heaters are a bit controversial; they are a new technology and in many cases they can perform abysmally. In other situations, they are a god-send. It really depends on the make of the tankless heater, its size and where it is used. In this piece, I want to take a harder look at how the size of the water heater can impact performance.

Tankless water heaters must be sized correctly for their usage or else they will break down faster or they won’t provide the amount of hot water you expect. For example, some tankless units will give out X amount of water a minute so long as the temperature is set high enough. This means that you will have to carefully inspect the unit before you buy it and understand the circumstances under which water will actually be released! Size matters in this point because the larger the possible output, the more water you can get at a lower temperature if you need to.


The Rinnai Tankless unit serves eight and half gallons of water a minute with a temperature rise of forty degrees. If the pre-set is at 120 degrees (standard) and the supply of water is less than 80 degrees, you won’t get any water until the water temperature rises to the pre-set. Obviously with a tank, you don’t have to worry about that. However, other units may have a lower pre-set or be more efficient at heating water. Shop around carefully!

Correctly sizing the tankless water heater also means that they can act as a supplement to the standard heaters. Custom homes in particular offer the scope for having small units in rooms which need hot water as a supplement to the tank; for example, the shower may have a small fixture to provide more hot water as necessary. Of course, this is a more expensive route and will probably only be suitable for high end housing, but it is an attractive asset for homeowners.

The big advantage of tankless water heaters size is also a disadvantage at times. In large homes, tankless water heaters are less practical than the conventional water heaters because larger homes chew through the hot water faster than the tankless heaters can heat it, meaning that there are still cold showers! In these cases, supplementary tankless water heaters are an option so that you don’t have to rely solely on a tank and you can purchase a smaller tank with fewer piping to cut down on the risk of leaks and damage.

The right size of tankless water heaters is pivotal if you are going to install one in your home. All tankless heaters tend to be small and this means they can only heat so much water at a time. If there are heavy demands on the hot water, the standard tank with supplements may work best. If it’s a small place with fewer demands, the small tankless water heater may be ideal. It’s all up to your situation and you should pay close attention to your given circumstance rather than to the hype.

Find out more on tankless hot water heaters on our website.

Clearview Plumbing and Heating is a Calgary Plumbing company based in Calgary, Alberta, Canada which is available round the clock to carry out any type of Calgary Plumbing job.

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Keywords: Calgary tankless water heater, tankless water heaters

By | 2018-05-26T11:36:14+00:00 March 12th, 2012|Hot Water Heaters, Plumbing Services|