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Hot Water Tanks vs Tankless Water Heaters: What to Consider


It’s no secret that access to water is pretty fundamental part of life. Access to hot water is just as critical (and some may argue even more so!). Whether it’s taking a nice hot shower so you’re ready for your day, pouring a cup of coffee or tea, preparing a meal in the kitchen, washing clothes or dishes, filling a warm water pack for a sore back, or even treating a minor wound, it’s pretty clear that without hot water we’d all be in, well, you get the idea. So today let’s look at how we use hot water in our homes and specifically how that water gets heated and delivered and why it’s important to make the right choice with water heating equipment.


While there are technically many ways to heat water, the way most of us choose to heat it for home use is via a Hot Water Tank usually located in the basement or utility room next to our furnace. Commonly, most homes will still be using a large cylindrical tank to heat and hold our household hot water at temperature until needed. This basic tank technology has remained largely unchanged for over 100 years aside from a few design and safety features.


Cold water from the building’s water mains is plumbed into the tank reservoir, heating elements heat the water to the desired temperature - usually 60C (140F) by default, and the tank then hold this volume of water (usually 40 or 50 Gallons) at this constant temperature until we call for it from one of our household hot water faucets. As this volume of hot water is used, cold water is gradually refilled into the tank reservoir to be heated again and ready when the next batch is called for.


Of course, the laws of thermodynamics require that these volumes of water take some time to bring up to temperature. Those of us in busy households with several bathrooms and lots of people going about their days are probably all too familiar with being the last one in the shower for the morning and having little or no hot water left! Still, with a little patience the tank eventually fills and heats again, ready to deliver more hot water as needed.


While this style of heating household water is “tried and true” and still able to provide sufficient hot water for a lot of households’ needs when sized properly for the home and the people in it, it does come with some downsides:


  1. Tanks’ volumes are limited and so is the hot water on demand. Not often a concern for 1-2 people with a sufficiently-sized tank, but can be a challenge with higher volume usage.
  2. These water tanks are generally quite large and take up a fair amount of space. On top of requiring adequate space to position and install, this can sometimes lead to cramped utility spaces that makes regular access and maintenance/repair difficult.
  3. Any volume of water, particularly hot water, is going to be dangerous and costly in the event of a leak or tank failure. Regular maintenance and inspection is important, as is knowing where the relevant inlet and power shutoffs are and being able to access them quickly in an emergency.
  4. Holding a volume of water at a high temperature is notoriously inefficient. When you consider how often (or how seldom) you use large water volumes, it pays (literally) to consider how much of your household’s energy bill goes into keeping all that water heated until needed.


Because of these reasons and perhaps a few others, more and more homeowners are switching to a newer, more efficient way to deliver their hot water – the Tankless Water Heater.


Tankless Water Heaters are gaining in popularity due to a number of factors. Principally, tankless water heats work by heating water as it’s needed and sending it to your faucet immediately rather than storing it at temperature 40 or 50 gallons at a time. While the initial investment tends to be higher than for a traditional water tank, the increased energy efficiency and limitless hot water availability (when sized properly) mean that going tankless for your home’s hot water carries several advantages:


  1. Energy efficiency. Not having to keep a large volume of water constantly at temperature even when not in use means if hot water isn’t being called for, no energy is being used.
  2. Space-saving. Rather than having a giant water tank taking up floor space in an already tight utility area, a suitcase-sized heating unit is attached to the wall and is easily accessible and out-of-the-way leaving lots of room to work and access other equipment in the room.
  3. Limitless hot water! When sized properly, because tankless heaters heat water as it’s called for, there is virtually no limit to how much hot water can be delivered. Water usage aside, if everybody wants to have a 30-minute shower on a chilly day, there is plenty to go around. No need to wait for a tank to refill and reheat – just tune your faucet to your desired temperature and the hot water will flow as long as it’s being asked to do so.
  4. While it is still important to be aware of water shutoffs and how to access them, because there is no reservoir holding large amounts of hot water, the danger of a large leak or flood is virtually non-existent.




With tankless technology continuing to improve and energy costs continuing to climb, going tankless is making more and more sense for homeowners looking to replace or upgrade their current Hot Water Tank. If you have a recently installed HWT in good repair and able to deliver hot water as needed most of the time, it may not be worth upgrading today, but when the time comes for replacement, switching to a tankless water heater is definitely worth having a free consultation with a professional to weigh the pros and cons and see if this water, energy, and money-saving technology is right for you and your family’s needs.