Things that You Should Know before Getting a Tankless Water Heater

Things that You Should Know before Getting a Tankless Water Heater
February 14, 2013 Lorelie
getting a tankless water heater

Getting a Tankless Water Heater

Are you currently out in the market looking for a water heater for your home and was wondering whether you should get a water heater with a tank or one that is tankless?  Most people have different opinions about what kind of water heater you should get for your home.  Some homeowners prefer the tank-type water heaters, while there are those who prefer the tankless ones.  If your mind isn’t made up yet, and you are interested in getting a tankless water heater, then there are 7 things that you should know before getting one:

The 7 things you should know before getting a tankless water heater:

1.  Find out about your hot water needs at home.  Most of the times, the flow rate of the hot water coming from a small tankless water heater is sufficient enough for a kitchen with a dishwasher and a bathroom.  The secret on how to choose the correct model is by knowing the specific flow rates of all your fixtures, your usage consumption (such as how many faucets does your family use usually at the same time), and the possible coldest temperature of the incoming water.  Ask your plumber to help you select a certain size of the tankless water heater unit that suits your needs.  Additionally, you can actually install more than one water heater unit to heat water by zone.  For instance, you can have two tankless water heater units in one house.  The first one can supply hot water needs for the bathroom and kitchen, while the second one can supply the washing machine and other bathrooms or fixtures.

2.  You need to decide wisely on where to place your tankless water heater unit.  Tankless water heaters utilize a strong flame in order to heat water on demand.  Thus, these units need more air for combustion and tend to vent more exhaust than traditional water heaters.  This actually affects where and how you install them in two ways:

Combustion air - Whether it is tankless or not, a gas-fired water heater needs an oxygen source for combustion.  Your water heater unit must be sealed-combustion direct-vent in order to prevent back-drafting that combustion air through another appliance’s exhaust pipe.

Venting – For through-the-wall direct venting, the vent termination should be 3 feet from any operable window.  If in case you are venting through the roof, then you should be aware that the vent length is determined by the water heater’s size (particularly the BTU output) and the number of elbows (or turns) in the vent.  If in case the vent run is long (such as if the water heater unit is in the basement of a 4-storey building), you might not be able to vent the water heater unit through the roof.

3.  Avoid very long runs between the water heater unit and the faucet.  Due to the fact that tankless water heaters generate hot water only if you turn on the hot water tap, it takes a few moments to heat the cold water to the desired optimal temperature.  Placing the water heater unit far away from the tap can typically result in a significantly more evident “sandwich effect” when hot water is occasionally used.  One way to solve this issue is by using a recirculation pump that brings water from the farthest fixture in the plumbing to run back to the tankless water heater unit; however, due to the fact that these recirculation pumps utilize a significant amount of energy in order to keep the water in the loop hot, it is certainly better to just buffer or preheat hot water.

4.  Know if your clothes washer and dishwasher really require a water heater unit supplied to them for your hot water needs.  If the situation calls for some hot water in your dishwasher or clothes washer, then you need to know if they might need hot water from your tankless water heater, or they may have the feature of heating water by themselves.  Most homeowners typically assume that their appliances such as the dishwasher and clothes washer need a water heater unit, but they may be surprised that their current clothes washer is capable of heating the water by itself and only needs a cold water connection.

5.  Inspect your water and gas supplies.  Tankless water heater units can actually produce about 3 to 4 times the BTUs that a traditional water heater usually produces.   Your plumber should make sure that your current gas line length, size and even the gas meter can deliver enough gas flow to the water heater unit.  Tankless water heaters need minimum water flows for activation as well.  Therefore, your plumber must also make sure that your supply meets the specifications.

6.  Expect that your contractor might reject the idea of getting a tankless water heater unit.  Because of issues on time and liability, it is common that many contractors do not like to try out something new.  If you have made up your mind that what you need is a tankless water heater, insist that you will get it and find a contractor who will be willing to work with you.  Find someone who actually has experience in installing tankless water heater units.  You can give the contractor the manufacturer’s installation instructions which are oftentimes available online, if in case it is not completely provided with the unit.  You might also like to get in touch with the manufacturer’s customer service/technical support department if you need some assistance or if you need advice on size and other concerns.

7.  Ensure that the venting material abides by the local building codes and the manufacturer’s specifications.  Did you know that there is a specific venting material for tankless water heaters?  The specific venting material for tankless water heaters is typically made from stainless steel.  It has built-in seals in order to prevent carbon monoxide from leaking into your house.  Depending on the design of your house, a double-walled material may be needed (you need to be aware that this is quite expensive).  Your HVAC contractor or plumber might miss this kind of specification.

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