How To Select The Right Size Tankless Water Heater

A tankless water heater can be an attractive alternative to a conventional storage water heater. Instead of storing hot water in a large tank, a tankless water heater provides hot water on demand, using gas or electricity. The most popular gas-fired model is the “demand” type; the most popular electric models are called “instantaneous” or “tankless on-demand.”

Tankless water heaters last longer than storage models and have no standby loss (electric models) or fuel loss (gas models). Some models can save you as much as 50% GPM off your monthly utility bill. However, they’re more expensive initially than conventional storage models, and they’re most likely too small to supply all of your hot-water needs. They’re also more complicated to install. If you use only a few gallons of hot water at a time, it may not be worth the investment.

One of the most common questions we receive is how to determine the correct size tankless water heater for your home. This is an important question because a tankless water heater will cost you thousands of dollars to purchase and install and if you get the size wrong, you could end up with a unit that doesn’t meet your hot water needs.

What you need to know when choosing a tankless water heater:
Size: One of the biggest decisions in choosing a tankless is how big you want to go. Manufacturers typically offer units that provide anywhere from .5 GPM to 6 GPM of hot-water flow for every 1,000 square feet of living space.

As an example, let’s say you are a typical family of four living in a three-bedroom home. You have two teenage children, who take long showers every morning and have friends over on weekends. During peak times, you need five gallons of hot water per minute. Your average daily usage is 70 gallons per day, and there are four people in your household. Here’s how to calculate the right size for you:

Peak time usage: 5 GPM x 4 hours (2 teenagers taking showers) = 20 gallons per day
Average daily usage: 70 gallons/day x 4 people = 280 gallons/day
Required size: 280 gallons per day / 70 gallons per day minimum requirement = 4

Flow Rates
A flow rate is typically measured in gallons per minute (GPM). The flow rate of a low-flow showerhead is 2.5 GPM and a high-flow head is 5 GPM or higher. Most homes have an average of 2.5-5 GPM fixtures but it’s important to know what you have because it will affect the size of the tankless water heater that you should choose.

Flow Rates for Various Fixtures are their typical Flow Rate is:

  • Shower 2.5 gallons per minute (GPM)
  • Hand Shower 1.5 GPM
  • Bathtub 2.0 GPM
  • Kitchen Sink 2.0 GPM
  • Dishwasher 2.0 GPM
  • Laundry Tub/Appliance 3.0 GPM
  • Washing Machine 4.0-6.0 GPM

Other Sizing Notes
In general, it is best to locate the tank near the point of use. However, additional pressure drops must be considered if several fixtures are located on a long pipe run or if there are significant elevation changes in the plumbing system. You may need to consider additional back-pressure valves to ensure adequate flow rates for all fixtures if this occurs.

If multiple fixture types are present in your home (for example, faucets with aerators), check to see that all fixtures can be accommodated by the same tankless water heater model.

Tubing: Tubing is the length of copper pipe between the tankless water heater and the faucet or showerhead. If you’re replacing an existing water heater with a tankless model, you’ll need to know where your current hot water lines are because they might not be long enough for a tankless model to work effectively.

A general rule is, if there are less than 25 feet between the tankless water heater and the fixture, you’re fine but keep in mind that every extra foot of tubing will drop the flow rate by half a gallon.

6 Signs Your Water Heater is About to Fail
Water heaters are the heart of the home. Despite their importance, most people don’t think about them until there’s a problem. You may be surprised to know that water heaters typically have a life expectancy of 8-15 years.
Contact our professional hot water system repair team today to avoid major issues within your hot water system in Australia.
While it’s important to have your water heater inspected annually, there are also a number of signs you can look out for that will help you avoid a water heater failure, and possibly an emergency situation.

The average lifespan of a water heater is about 10 to 12 years, though some make it up to 20 years. The best way to know when your water heater is getting old is to monitor it regularly. Here are 6 signs that it’s probably time to replace your water heater. If you notice any of these signs that your water heater is likely about to fail and you should contact us today!
1. Taps or Knocking Sounds
If your water heater has been making strange noises, chances are it’s on its last leg. This can be caused by sediment collecting at the bottom of the tank. Sediment buildup is common in water heaters that are over 10 years old and should prompt you to consider a replacement. When this happens, the tank needs to be flushed out before repair or replacement can occur. Other potential problems include a faulty pressure relief valve and a malfunctioning heat exchanger.
2. Not Enough Hot Water
If your hot water isn’t as hot as it used to be, this could be your first sign that something is wrong with your unit. Older units can experience reductions in hot water output due to sediment buildup or corrosion of the heating element. You may also experience a lack of hot water if the tank is damaged or if the thermostat is faulty. An experienced plumber or gas fitter should be able to fix this problem or advise if it needs replacing.
3. Temperature Fluctuations:
If you notice your water temperature varies greatly throughout the day, this could be a sign that your heater is failing. The fluctuation in temperature will depend on how old your particular model of the heater is. Newer models can have temperature fluctuations within degrees while older models have temperature fluctuations within ranges up to 30 degrees celsius.
4. Leaks
Leaks could indicate a major problem with your water heater. Leaks are usually caused by corrosion around pipes and fittings, broken seals or worn-out gaskets. A good plumber will be able to find the source of your leak and fix it up for you before it becomes irreparable.
5. Cloudy or Odd-Smelling Water
Cloudy or odd-smelling water is typically an indication that bacteria has started growing in the tank as a result of organic matter. If your water tastes like metal or has an unpleasant odour, this could be a sign that something is wrong with your hot water heater. It could have a buildup of sediment which is affecting the taste and smell of your water. If this happens, you should get in touch with a plumber right away to find out what the problem is and to fix it as soon as possible.

Cloudiness is also a sign that lime or scale buildup has occurred. In either case, it’s necessary to enlist the help of a professional to clear blockages for safe operation and to prevent long-term damage to the system.
Things to Consider When Replacing Your Water Heater
Replacing your water heater seems like a pretty straightforward project, but it’s actually a lot more complicated than you might think. You need to think about how old your current water heater is, what type of water heater you want to buy and how much money you’re willing to spend on it. This can be daunting, especially if you haven’t replaced your water heater in the past. If you’re in this situation, give Anytime Hot Water a call and we can assist you in making the best decision.

What do I need to know before replacing my water heater?
To make an informed decision, you need to know how much it will cost to replace your water heater and what you’ll get for your money. Here are some other important things to consider when replacing your water heater:

Size: The most common mistake people make when replacing their water heater is purchasing one that’s too small for their household needs. It’s tempting to just buy the smallest and cheapest possible size for the job, but this isn’t always a good idea.
Your future need: It’s also important to take into consideration your future needs. If you have plans for an addition or other expansion down the road.
Energy Efficiency: The most important thing to consider when replacing an old water heater is how efficient the replacement model will be. A new gas or electric model will have better insulation and circuit boards for more precise temperature control than an older unit. In addition, models with condensing boilers can save you even more money on gas bills by converting excess heat into usable hot water.
Tubing and fittings: Before purchasing a water heater, estimate the length of tubing that’s required to connect the new heater to the existing plumbing. You should also purchase enough fittings (elbow, tees, and so on) to connect the tubing from the heater to the cold-water pipe. You may have to purchase additional fittings if you have unusually long or difficult plumbing runs.
Warranty: Most water heaters come with a limited warranty that includes labour costs for the first year or so. Check both the length of the coverage you will receive before making your purchase.
Insulation: Some replacement water heaters include thermal insulation kits that reduce condensation and energy loss by as much as 30%. It’s usually worth a few dollars more in price to save on heating bills over time.

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