Favored in Europe and Japan for several years, "on-demand, tankless" water heaters are now getting more often found in Northern America, especially for new houses. Tankless heaters are relatively compact wall-mounted units, fueled either by gas or electricity that are built to produce hot water only when needed. When a hot water tap is turned on at a household fixture, cold water starts to flow through coils in the unit and is instantly heated to a preset temperature then distributed to the plumbing fixings throughout the house.

When first introduced years back, few builders or house owners were interested because of their comparatively high price and some trustworthiness issues. But the continuing escalation of fuel costs and the redesign of many units to get rid of some of the earlier issues has led on to replenished interest, basically in new construction But for replacement of old or leaking standard tank-type units too. The key benefits touted in the marketing of these units are their energy efficiency, limited space necessities, and ability to supply hot water whenever required.

While these units will supply hot water on demand, they are not designed for high water volume. Generally tankless heaters provide satisfactory hot water at a normal water flow rate of Two to 4 gallons per minute. They can provide adequate hot water so long as the draw through the system does not exceed design ratings. Nevertheless if there’s a requirement for hot water from a lot of different fixings at one time, a tankless heater may not be able to keep up.

Most of these units also have an effective minimum operating flow rate and pressure. Hot water may continue to be produced however ; the high volume will end up in a lower supply temperature. At very low flow rates, for instance, less than 0.5 gallons a minute, the unit may stop manufacturing hot water. The most important reason for this limitation is that it is tough to maintain a safe water supply temperature at low water flow rates.

To meet an anticipated heavy demand, multiple tankless heaters can be installed at one central location, or one or two units can be distributed throughout the house. A tankless unit may also be used as an indirect heater by installing an insulated storage tank.

When considering installing one of those units, homeowners must look at all the costs and benefits versus storage tank type units. For existing homes, the routing and size of gas lines and exhaust vents are issues that may add to the price tag. Review specific manufacturer info and realize that, at least initially, making the switch to a tankless heater will likely mean some changes in hot water usage patterns .