Barron Heating AC Electrical & Plumbing Blog: Archive for the ‘Tankless’ Category

Why Switch to a Tankless Water Heater?

Monday, October 16th, 2023

Your water heater works fine, so why bother switching to something new when you don’t feel the need to? The fact of the matter is this: the world is switching away from tank-style water heaters, and for good reasons.

While going tankless may seem daunting at first, we’re here to tell you that it doesn’t have to be difficult or the least bit concerning. (Actually, it can save you money on your monthly bills.) Let’s take a look at tankless water heaters and why you might use one to replace your current water heater.

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Water Heaters: The Real Deal on Tankless v. Tank

Tuesday, April 7th, 2015

Take a look at the following terms: Tankless Water Heater, Standard Natural Draft Water Heater, Standard Induced Draft Water Heater, and On-Demand Hot Water. Do they all make sense to you?

If you’re like me, you thought you understood them. Tankless…. pretty obvious, right? NO TANK. But like most things, there’s a lot more to it than meets the eye. There’s actually a pretty big debate when it comes to whether to tank or not to tank. And, because hot water accounts for 20% of people’s energy bills (on average), it’s something to seriously consider. Let’s walk through some of what a Tankless is and is not to dispel some common misconceptions.

What Tankless is…

Tankless is small, compact, efficient with it’s energy use, and (whoa) this one’s big: endless hot water. My sixteen year old self could have really used one of these. Also, they’re just pretty cool technology. There’s basically a long coiled pipe inside a small (briefcase sized) box on the wall. When the water enters, the pipes heat up and when the water leaves the box, it’s hot!

This is all well and good, except that like most really nifty things, they come with a price. Tankless Water Heaters are, on average, about twice as much money as a standard tank. That’s a big investment. But IS it an investment? This is where the debate comes in. Unlike a lot of energy-saving home purchases (of which we are big advocates), the point where monthly savings on hot water add up to pay off your investment of a Tankless can be about the time it wares out from old age (around 20 years), particularly when using natural gas.

What Tankless is not…

Tankless is not On-Demand hot water. This was news to me. Something as high-tech and expensive as Tankless should come with all the bells and whistles, right? The truth of the matter is that Tankless takes slightly longer to deliver hot water to the tap unless a recirculating unit is installed. The water comes into the box cold (as opposed to the constant heating of a standard tank), so when you turn on the tap to wash your hands or take a shower, it will take about 5 seconds more to receive that heated water. The water has to work it’s way through that coil until the coil has reached operating temperature.

Tankless is also not always the most cost-effective choice in a replacement situation. What? Yes. While the constant-heating of a standard tank is energy-intensive, and seems inefficient, if you’re family is using up all the hot water in the tank throughout the day, it’s basically acting like a tankless. Let’s say a family of 4 is taking a couple showers, a bath, a load of dishes, and a load or two of laundry per day (this is, coincidentally what our day often looks like at home). With our 40 gallon tank, we are using that sucker up, over and over.

Another thing to consider is that while neither technology is exempt from occasional repairs and annual service, Tankless is less forgiving of missed maintenance.

Here is one of our service techs, Colin, servicing a customer’s Rinnai brand tankless water heater. He is descaling the heat exchanger due to mineral deposits coating the heat exchanger surfaces and acting as an insulator decreasing heat transfer. The severity of this condition depends on water quality but it happens in all applications and on all water heaters (tank or tankless).
Most people know that corrosion is a big issue with standard water tanks, but clearly, it is something to watch for in tankless models, too.

Standard Tank (induced or natural draft)

If you are considering purchasing a Standard Tank Water Heater the big thing to remember is that though the various models and types look similar on the outside, they are definitely not all created equal. The main things to think about are: Fuel-type, Draft-type, and Warranty Length.

Fuel-type: Natural gas is significantly more affordable than electric or propane in most places. Natural gas models are more expensive up-front, but the investment pays off fast. In fact, the savings you’ll see in your energy bill (around half as much) will usually make up the difference in cost (between electric and gas) in about a year. Oil-fueled Water Heaters exist too, but are rare because of the very high cost.

Draft-type: A natural-draft water heater means that the combustion gases (including carbon-monoxide) come out the top of the water heater naturally, and therefore have the risk of back-drafting. These water heaters are fine, but are best installed outside the building envelope. Having one of these in your home could be dangerous. In some situations, the water heater cannot be replaced with a standard atmospheric vent water heater due to newer mechanical codes. Talk to your HVAC professional to be sure. Induced-draft means that the gases are driven out of your home through a pipe and fan-system, which can be much safer.

Warranty Length: A longer warranty length may not sound like an important factor at first, but it really shows how confident a manufacturer is in it’s product. The warranty-length neatly bundles a lot of the questions regarding internal options of tank-style water heaters. This piece from Consumer Reports has a ton of GREAT information. They go through all the nitty-gritty like internal tank features, safety concerns, and even specific brands. But the most concise info I took away from it on water tanks is: “Those with longer warranties tend to have larger heating elements, thicker insulation, and thicker or longer corrosion-fighting metal anodes.”

Quick List of Pros/Cons

So the easiest answer to the whole question of what kind of water heater is best is: It depends on your family and your needs. Let’s break it down into a pros and cons list for convenience:

Tankless – Pros

  • Endless hot water
  • Energy Efficient (only heating the water used; better combustion)
  • Compact, space-saving
  • Easier to service (descale corrosion)
  • Longer life (about 20 years)
  • Decent ROI for propane-fuel homes

Tankless – Cons

  • Up-front cost (about twice as much as a standard tank)
  • Natural gas customers don’t see an ROI, because energy savings don’t make up for the cost
  • Slightly longer wait time to receive hot water

Standard Tank – Pros

  • Natural Gas models are fairly energy efficient (not quite so much as tankless)
  • Up-front cost (about half as much as a tankless)
  • Not as much of a delay in hot water reaching the tap in most homes

Standard Tank – Cons

  • Constantly heating a huge tank of water (that may not be getting used throughout the day). Inefficient (for some families).
  • Corrosion issues and mineral build-up occur within the tank and can’t always be seen or remedied
  • Not Efficient
  • Require a lot of space
  • Shorter lifespan (7-12 years)

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Water Heater Facts

Thursday, October 3rd, 2013

What is the average lifetime of a gas water heater?

The average lifetime of gas water heater is 9 years. The range is 5-14 years.

How are FHR and Therms used to compare the efficiency of water heaters?

The first hour rating (FHR) tells you the number of gallons per hour of hot water. Therms relate to the gas consumption of water heater. When you are shopping for hot water heater, compare the energy factor on the energy guide label. FHR and Therms are not sufficient to calculate the energy factor. Also remember to compare water heaters of equal capacity and FHR.

What efficiency standard does a dual use residential water heater need to meet as a water heater or a boiler (used for both potable water and space heating purposes)?

For a dual unit, it must meet the efficiency standard requirements of both applications. Your local building department may have additional requirements for such units.

What is a hot water recirculating system?

A “hot water re-circulating” system usually refers to a domestic hot water system that circulates the heated water through the house continuously so as to eliminate or shorten the delay in hot water reaching the faucet after the user turns it on. These systems are most common in multifamily or large building applications where otherwise the delays would be truly unacceptable. They can be real energy hogs if the pipes aren’t well insulated.

How do I choose the best electric or gas tankless water heater for my home (2300 sq. ft.)?

Sizing of hot water heaters should be based on the number of occupants and their peak hour water demand and not on the size of the house.

Posted by Wes Diskin

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Facts About Selecting A Water Heater

Wednesday, September 25th, 2013

Summary:

This fact sheet will help you select an energy-efficient water heater for your home. Many homeowners wait until their water heater fails before shopping for a replacement. Because they are in a hurry to regain their hot water supply, they are often unable to take the time to shop for the most energy-efficient unit for their specific needs. This is unfortunate because the cost of purchasing and operating a water heater can vary greatly, depending on the type, brand, and model selected and on the quality of the installation. To avoid this scenario, you might want to do some research now before you are faced with an emergency purchase. Familiarize yourself today with the options that will allow you to make an informed decision when the need to buy a new water heater arises.

Types of Water Heaters Available Within the last few years, a variety of water heaters have become available to consumers. The following types of water heaters are now on the market: conventional storage, demand, heat pump, tankless coil, indirect, and solar. It is also possible to purchase water heaters that can be connected to your home’s space-heating system.

Storage Water Heaters

A variety of fuel options are available for conventional storage water heaters electricity, natural gas, oil, and propane. Ranging in size from 20 to 80 gallons (75.7 to 302.8 liters), storage water heaters remain the most popular type for residential heating needs in the United States. A storage heater operates by releasing hot water from the top of the tank when the hot water tap is turned on. To replace that hot water, cold water enters the bottom of the tank, ensuring that the tank is always full.

Because the water is constantly heated in the tank, energy can be wasted even when no faucet is on. This is called standby heat loss. Newer, more energy-efficient storage models can significantly reduce the amount of standby heat loss, making them much less expensive to operate. To determine the most energy-efficient model, consult the EnergyGuide label required on storage water heaters. EnergyGuide labels indicate either the annual estimated cost of operating the system or energy efficiency ratings.

Demand Water Heaters

It is possible to completely eliminate standby heat losses from the tank and reduce energy consumption 20% to 30% with demand (or instantaneous) water heaters, which do not have storage tanks. Cold water travels through a pipe into the unit, and either a gas burner or an electric element heats the water only when needed. With these systems, you never run out of hot water. But there is one potential drawback with demand water heaters — limited flow rate.

Typically, demand heaters provide hot water at a rate of 4 to 6 gallons per minute. This flow rate might suffice if your household does not use hot water at more than three locations at the same time (e.g., showering, dishwasher and doing laundry simultaneously). To meet hot water demand when multiple faucets are being used, demand heaters can be installed in parallel sequence.

Heat Pump Water Heaters

Heat pump water heaters use electricity to move heat from one place to another instead of generating heat directly. To heat water for homes, heat pump water heaters work like refrigerators in reverse. Heat pump water heaters can be purchased as integral units with built-in water storage tanks or as add-ons that can be retrofitted to an existing water heater tank. These systems have a high initial cost.

They also require installation in locations that remain in the 40 degree to 90 degree F (4.4 degrees to 32.2 degrees C) range year-round and contain at least 1000 cubic feet (28.3 cubic meters) of air space around the water heaters. To operate most efficiently, they should be placed in areas having excess heat, such as furnace rooms. They will not work well in a cold space.

Tankless Coil and Indirect Water Heaters

A home’s space-heating system can also be used to heat water. Two types of water heaters that use this system are tankless coil and indirect. No separate storage tank is needed in the tankless coil water heater because water is heated directly inside the boiler in a hydronic (i.e., hot water) heating system. The water flows through a heat exchanger in the boiler whenever a hot water faucet is turned on. During colder months, the tankless coil works well because the heating system is used regularly.

However, the system is less efficient during warmer months and in warmer climates when the boiler is used less frequently. A separate storage tank is required with an indirect water heater. Like the tankless coil, the indirect water heater circulates water through a heat exchanger in the boiler. But this heated water then flows to an insulated storage tank. Because the boiler does not need to operate frequently, this system is more efficient than the tankless coil. In fact, when an indirect water heater is used with a highly efficient boiler, the combination may provide one of the least expensive methods of water heating.

Solar Water Heaters

Through specially designed systems, energy from the sun can be used to heat water for your home. Depending on climate and water use, a properly designed, installed, and maintained solar water heater can meet from half to nearly all of a home’s hot water demand. Two features, a collector and a storage tank, characterize most solar water heaters. Beyond these common features, solar water-heating systems can vary significantly in design. The various system designs can be classified as passive or active and as direct (also called open loop) or indirect (also called closed loop). Passive systems operate without pumps and controls and can be more reliable, more durable, easier to maintain, longer lasting, and less expensive to operate than active systems. Active solar water heaters incorporate pumps and controls to move heat-transfer fluids from the collectors to the storage tanks. Both active and passive solar water-heating systems often require conventional water heaters as backups, or the solar systems function as preheaters for the conventional units. A direct solar water-heating system circulates household water through collectors and is not appropriate in climates in which freezing temperatures occur. An indirect system should not experience problems with freezing because the fluid in the collectors is usually a form of antifreeze. If you are considering purchasing a solar water-heating system, you may want to compare products from different manufacturers. The Solar Rating and Certification Corporation provides a benchmark for comparing the performance of some solar water heating systems.

The SRCC publishes performance ratings of both solar water-heating systems and individual solar collectors. These published ratings are the results of independent, third-party laboratory testing of these products. All systems and collectors that have been certified by the SRCC will bear the SRCC label. Keep in mind, though, that simply having an SRCC label does not imply that the product has a superior performance. Carefully compare SRCC label information on different brands and models to ensure that you are fully aware of projected performance. The Florida Solar Energy Center also provides information on solar manufacturers and contractors. It also maintains solar equipment testing facilities and publishes performance ratings for solar water heating systems. Just choosing a solar water heater with good ratings is not enough, though. Proper design, sizing, installation, and maintenance are also critical to ensure efficient system performance. Although the purchase and installation prices of solar water heaters are usually higher than those of conventional types, operating costs are much lower. For more information about solar water-heating systems, contact the Energy Efficiency and Renewable Energy Clearinghouse.

Criteria for Selection

As with any purchase, balance the pros and cons of the different water heaters in light of your particular needs. There are numerous factors to consider when choosing a new water heater. This publication has already described different system configurations. Some other considerations are capacity, efficiency, and cost.

Determining Capacity

Although some consumers base their purchases on the size of the storage tank, the peak hour demand capacity, referred to as the first-hour rating (FHR) on the EnergyGuide label, is actually the more important figure. The FHR is a measure of how much hot water the heater will deliver during a busy hour, and it is required by law to appear on the unit’s EnergyGuide label. Therefore, before you shop, estimate your household’s peak hour demand and look for a unit with an FHR in that range. Gas water heaters have higher FHRs than electric water heaters of the same storage capacity. Therefore, it may be possible to meet your water-heating needs with a gas unit that has a smaller storage tank than an electric unit with the same FHR. More efficient gas water heaters use various nonconventional arrangements for combustion air intake and exhaust. These features, however, can increase installation costs.

Rating Efficiency

Once you have decided what type of water heater best suits your needs, determine which water heater in that category is the most fuel efficient. The best indicator of a heater’s efficiency is its Energy Factor (EF), which is based on recovery efficiency (i.e., how efficiently the heat from the energy source is transferred to the water), standby losses (i.e., the percentage of heat lost per hour from the stored water compared to the heat content of the water), and cycling losses. The higher the EF, the more efficient the water heater. Electric resistance water heaters have an EF between 0.7 and 0.95; gas heaters have an EF between 0.5 and 0.6, with some high-efficiency models around 0.8; oil heaters range from 0.7 to 0.85; and heat pump water heaters range from 1.5 to 2.0. Product literature from manufacturers usually gives the appliance s EF rating. If it does not, you can obtain it by contacting an appliance manufacturer association (see Source List). Some other energy efficiency features to look for are tanks with at least 1.5 inches (3.8 centimeters) of foam insulation and energy efficiency ratings shown on the EnergyGuide labels.

Comparing Costs

Another factor uppermost in many consumers’ minds is cost, which encompasses purchase price and lifetime maintenance and operation expenses. When choosing among different models, it is wise to analyze the life-cycle cost — the total of all costs and benefits associated with a purchase during its estimated lifetime. More information on conducting life-cycle cost analyses is available from EREC. Units with longer warranties usually have higher price tags, though. Often, the least expensive water heater to purchase is the most expensive to operate.

Posted by Wes Diskin

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