High efficiency tankless water heaters are in greater demand than ever. Not only do these units have efficiencies rated in the mid-90’s, but they also offer easy installation with contractor friendly PVC venting.
In the past most tankless water heaters were vented with category III AL29-4C Stainless Steel Vent Pipe which was very pricey. Improved designs in tankless condensing technology and the use of secondary heat exchangers to lower combustion gas temperatures have paved the way for PVC venting to be used.
Cost difference between a condensing tankless water heater and a standard tank-type water heater?
We get this question a lot and usually warn the customer that there is quite a bit difference in costs and installation labor costs. PVC Venting has made installation costs lower than ever and making tankless heaters more attractive for end users. Federal tax credits and local gas company rebates also help with purchase costs. The numbers vary by location, but most consumers can expect to pay 25% to 40% more for a quality tankless unit.
Some key issues to focus on when selecting a tankless unit:
- Venting Costs
- The cost of PVC venting in 2011 is about $1.50/ft compared to the average cost of Category III Stainless Steel vent at $26.50/ft.
- Condensing tankless units which offer the ability to vent in PVC will greatly reduce the costs of installation. o
- Venting in warmer climates in the United Sates offers a significant advantage. In warmer climates tankless water heaters are usually mounted outdoors eliminating the cost of vent material.
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- Gas Line Size
- In some cases a larger gas line may be required. Conventional tank type heaters are usually 40,000 to 50,000 BTU and require a ½” gas line. High efficiency condensing tankless water heaters usually modulate up to 199,000BTU which may require a larger gas line. It is important to make sure the contractor calculates proper gas supply sizes and the gas draw.
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- Condensation
- High efficiency condensing tankless water heaters produce condensate in the flue. Condensate is an acid-water mixture that must be handles properly according to local codes. A condensate neutralizer is often used to neutralize condensate before being routed to a drain. It is important for the contractor to follow local codes when disposing of condensate.
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- Flow Rates
- Watch flow rates of the tankless water heater selected. Catch phrases like “Endless Hot Water” and “Never take a cold shower again” confuse consumers and produce a falsehood that all tankless units will work. The key to remember is tankless water heaters are sized base on flow rates. Fixture counts must be used to calculate GPM required for a certain application. Each application is different and there are many variables to consider when sizing a tankless water heater.
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