Why Consider a Tankless Hot Water System?
Water heating accounts for 20-25% of an average household's annual energy expenditures. The yearly operating costs for conventional gas or electric storage tank water heaters average $200 to $800, respectively. Most tankless models have a life expectancy as long as 15 to 20 years. In contrast, storage tank water heaters last 5 to 15 years. Most tankless models have easily replaceable parts that can extend their life by many years more. These systems have been common in Japan and Europe for years, but are gaining attention now in North America. Tankless systems are more expensive to install than traditional tank systems, but substantial B.C. and Federal grants are available and vary from year to year.
About Tankless Water Heaters
The main advantage of these instantaneous water heaters vs. storage is tank-less design, continuous flow and endless supply, less energy consumption (up to 30-40% when comparing it to tank-type heaters), therefore more savings for you and no worry about running out of hot water during showers.
Comparing tankless water heaters with storage heaters that are heating water even when you are away or not using it, tankless hot water heaters work only when you open the hot tap.
On demand water heaters can use gas or electricity. The size of the instant water heaters you need depends on demand, how big your house is and the family size. Some manufacturers offer a multi-system set-up that can link many heaters into one system, to satisfy demand even for the largest houses.
Majority of these units are whole house tankless hot water heaters, as they have higher GPM flow rate capacity, so they handle demand for more than one application at a time.
How Tankless Water Heaters Work
There are some tankless heaters where heating element is controlled by the flow-sensing device that operates with a constant heat input and maximum flow rate. Flow rate depends on the pressure which can be adjusted on the knob.
If there is a request for maximum flow, the outgoing water toward the hot water tap is cooler since it spends less time passing through the heat exchanger.
Modern tankless models are using the latest technology where the output temperature, flow, safety and other parameters are controlled and regulated by the electronic circuit board.
When you open the hot water tap a flow sensor in the tankless hot water heater sends the signal to the electronic module. From there signal goes to the gas valve to open the gas flow.
If all the requirements are met, natural gas or propane flows into the burner located inside the combustion chamber. The gas is ignited either by the pilot flame or spark from the electrode.
Burning gas heats the heat exchanger where incoming cold water is quickly heated to the pre set and desired temperature. The heat exchanger transfers the heat from the burner to the water heating instantaneously. A vent pipe vents products of combustion out using the direct vent or powered vent system.
Once the faucet is turned off, the flow stops and flame goes out. As it can be seen from the above explanation tankless water heaters heat the water on demand, while providing you with an endless supply of hot water. You can see them often installed on the wall.
Tankless Water Heaters Reviews by fuel source:
Electric tankless hot water heaters have a compact design, saving you lots of space. They have a long service life as they are less prone to hard water and sediments. You can choose point-of-use or whole-house water heaters. Electric tankless water heaters don't produce greenhouse gases. Top selling brands in North America are Bosch PowerStar, Titan, Stiebel and Eemax.
Gas tankless hot water heaters are environmental friendly appliances also. Many of them utilize advanced technology for energy efficiency, and meet strict emission standards. They can use natural gas or propane - LP. Gas tankless water heaters produce higher flow rates than electric ones.
Tankless hot water heaters can be further divided into two categories; one that can only work as on/off and the other with modulation.
Instantaneous water heaters with modulation, base the heat output on the flow. For example if the demand for hot water is higher, modulating gas valve provides more gas and the final result is more power.
The following video (American—but very succinct) give a clear notion of how the system works.
Tankless hot water heaters are great. You save a lot of money creating hot water only when you need it. Good article. Hopefully, eventually we can all have these in our homes and save the energy required to keep conventional hot water heaters running.
Posted by: Plumbing Contractor | 10/13/2011 at 03:32 PM
It's a common residential problem, the unstoppable growth of water heater yearly expenditure. Many company offers heating systems that says can help you save energy consumption, some says it work faster and durable...but logically most of them didn't work.
Posted by: Water Heaters Indiana | 03/05/2012 at 12:56 AM
This sound interesting. I hate when the hot water runs out in the middle while taking a shower. Problem is that Tankless Water Heaters are not common at all in Israel, where I come from. Any information about Tankless Water Heaters in Israel?
Posted by: hotwater heater | 03/12/2012 at 08:10 AM
Read the article through once and must say you have peaked my interest. I didn't know there were so many types of water heaters. I tankless one seems really beneficial but only in certain circumstances. Thanks for the info.
Posted by: Christopher Pia | 03/30/2012 at 12:23 PM