Most Canadians have been heating water in either an electric or gas-fired tank in which water is also stored.

I am sure you have heard of tank-less water heater or hot water on demand, though you may not be sure how they work or if they are any good.

Also known as instantaneous water heaters, they have been popular in Europe for decades, primarily because they take up so little space – a major concern in Europe’s crowded cities where almost everyone lives in an apartment.

On-Demand Water Heater

Using high power, a tank-less water heater instantly heats water as it runs through the heater. It’s that simple. There is no storage tank involved and therefore no heat loss. A compact, on demand water heater is typically placed close to the tap where hot water is required, thereby providing hot water within a couple of seconds once the tap is opened. A flow sensor switches the unit on as soon as water starts moving and off again when the flow stops.

Advantages

• Long-term energy savings: tank-less heaters are more efficient than traditional hot water tanks
• Savings in water use because you don’t have to run water as long before you get hot water
• Unlimited hot water. Hot water tanks cool down as you draw water from them
• Less space required
• Water temperature and pressure are stable thanks to built-in bypass and mixing valves
• Safety: water temperature is more precisely controlled, eliminating temperature fluctuations and spikes
• Capacity is never reduced by sludge build-up, as in a traditional hot water tank

Disadvantages

• More expensive than most hot water tanks, though energy savings will eventually offset the difference
• Fewer possible energy sources. Tank-less systems are fired by gas or electricity only
• Flow-dependent temperature; e.g. – adjusting shower temperatures may take a little practice
• Water flow from a single tankless heater may not be enough to take a shower while your dishwasher is running. However, larger units are available that can supply two users at once

Energy Savings

Traditional hot water tanks incur heat loss as the water in the tank cools, which doesn’t happen with an on demand system. Also, tank-less heaters are on average 25% more efficient at heating water, thereby increasing savings related to energy use. Savings vary from one location to another and should be calculated before you make a choice.

Is a Tankless Water Heater Right For You?

In the long run, fuel savings together with a longer life expectancy make on-demand water heaters more economical than hot water tanks. But there’s more to it than that. If you are in the market for a new water heater, consult a professional to help determine which kind of water heater best suits your needs.

Some of the biggest companies that manufacture traditional hot water tanks also make tank-less heaters. Rheem water heaters and Bradford White water heaters are available in the Vancouver area from Efficient Furnace, a division of Good Guys Heating Cooling and Plumbing Ltd.

By: Andrew Lake