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Tankless Water Heaters
One appliance that is becoming very popular here in the South Carolina Lowcountry is a tankless propane water heater. Compared to traditional tank type heaters, tankless water heaters provide:
- Energy savings.
- Near zero energy cost if no hot water is used.
- Less work for your air conditioner.
- Unlimited supply of hot water.
- Life expectancy twice that of tank heaters.
- Space savings (no big tank needed).
- Installations inside or outside your home.
The largest energy consumer in your home besides the heating and air conditioning system is the water heater.
Traditionally, a water heater is a big tank with a heat source — either electric or gas. The water is kept hot so it is available when needed. Unfortunately, one thing the hot water is doing as it is waiting to be used is cooling. Of course, it must be continually reheated.
The heat that comes off a traditional tank type water heater does not just disappear — your air conditioner has to remove it, thus it costs you twice. The water that you pay to heat loads down your air conditioner.
A tankless water heater heats water only as it is used. Cool water enters the heater and hot water leaves it. If no hot water is needed, there is no energy used.
An obvious question is how fast can the water be heated? Propane tankless heaters can easily heat 8 or 10 gallons per minute. That is enough to supply 3 or 4 showers running simultaneously.
With a tankless water heater, you never have to be concerned about running out of water. That can be good or that can be bad. If you have a teenager who likes hour long showers, you cannot depend on running out of hot water to end the shower. The good thing is if you have company, you don’t have to worry about running out of hot water then either.
Another question that quickly comes to mind is how long do they last? Typically, a traditional tank type heater will last about ten years. Reportedly a tankless one can be expected to last about twice as long.
An Exterior Tankless Water Heater in a Remodel Application.
Corrosion occurs much faster when a device is hot and remember a tankless water heater is cold most of the time. On the other hand, a tank type water heater is hot all of the time (hopefully). Accelerated corrosion occurs continuously in a tank type heater and only during short intervals in a tankless water heater. It is easy to understand why tankless water heaters should outlast tank type heaters.
Generally, tank type water heaters are a little less expensive to purchase if you consider only the initial purchase. Installation costs are typically about the same for tank type or tankless systems. If you consider the fact that the life of a tank type system is much less than a tankless, the overall cost tips in favor of the tankless without considering energy savings. Also, a tankless heater can easily replace two or three tank heaters.
Space savings is another advantage of a tankless system. The tankless water heater can be mounted inside or outside. The heaters can be mounted on the wall or in the wall as shown in Illustration 1 above. If the heaters are mounted inside, they will need an exhaust vent. Once installed, they blend very well with the siding.
How much savings can you expect from a tankless propane water heater? According to Energy Guide stickers required by the U. S. Department of Energy, a family of 4 using 500 gallons of hot water per week would use about $450 per year heating water with an electric tank heater. A propane tankless would cost about $176 per year.
Rinnai and Noritz are two of the premiere tankless water heater manufacturers.
Further details can be found in the white paper Propane as Primary Energy Source for Water Heaters published by the Propane Education & Research Council. This paper can be found at: www.buildwithpropane.com/html/files/water-heater-white-paper.pdf.
If you have questions, please call us (843) 846 - 2500. We can help.