With tankless or on demand water heaters, proper sizing is also important.
Manufacturers rate the delivery of hot water in L or gpm. Consider how many users will be demanding hot water at the same time. If you expect that more than one shower or other appliance (such as a dishwasher) will be operating at one time, these demands must be added, and the water heater must be able to meet these peak loads. You may decide that operating the dishwasher can wait, and that is fine as long as everyone understands the availability of hot water.
Note that the capacities for delivering hot water that are quoted by manufacturers for both storage tank units and tankless units are based on raising the water temperature by a fixed amount. The temperature of the incoming water varies greatly by geographical location and time of year.
The other factor relating to sizing tankless water heaters is the capacity of the energy supply. Replacing a conventional storage tank water heater with a tankless gas-fired water heater may require that the gas supply to the water heater be increased. For example, a gas-fired tankless water heater will typically require a 1.9-centimetre (cm) (¾-inch [in.]) supply compared with a 1.2-cm (½-in.) supply for a standard water heater.
You can decrease water heating costs significantly in your home without replacing your water heater. The key is to use hot water more efficiently, so you need less of it without sacrificing comfort and convenience. Switching to water-saving fixtures and making a few simple adjustments to your existing water heater are great ways to start.
TIP #1: Take a shower instead of a bath.
A 5-min shower using a water-saving shower head uses only half the hot water that taking a bath does (see Tip #6 for an easy test to determine if your shower head is water-efficient).
TIP #2: Reduce the water flow while you soap up or apply shampoo.
Some low-flow shower heads have a “trickle” valve that reduces the flow of water (without adjusting the faucets) while you apply soap or shampoo. Save even more by turning off the shower while you apply soap or shampoo.
TIP #3: Turn the hot water down or off while you shave or wash dishes.
This apparently insignificant step, as opposed to letting the water run fully, can have significant results when practiced routinely.
TIP #4: Wash and rinse clothes in cold water.
About one-fifth of the hot water used in a typical house is for laundry. Most of the cost of operating washing machines is for heating the water. However, some detergents are now specifically formulated to dissolve in cold water. Cold water use may make clothes last longer. Cold water can be used for washing most laundry loads and is always sufficient for rinsing. If you do use warm water for some loads, adjust the water temperature and the water level for the size of the load.
TIP #5: Fix hot water leaks.
A leak of one drip per second of hot water from a faucet or shower head costs about $1 per month, yet often could be repaired in a few minutes and for a few cents with a new washer.
TIP #6: Install water-saving shower heads.
Low-flow shower heads can reduce hot water consumption by 30 percent, yet still provide a strong, vitalising spray. Look for a shower head that has a flow rate of less than 9.5 L/min. Many styles are available. Because personal preferences vary, consider purchasing a shower head that has an adjustable spray. Avoid low quality shower heads that may simply restrict water flow and result in poor and annoying performance.
TIP #7: Install water-saving aerators on the kitchen and bathroom faucets.
Check the flow rate of your faucets by the same method used for the shower head. Replace aerators on faucets that use more than 14 L/min of water. (A 2-L cardboard milk carton fills in less than 8 to 10 sec.)
Select water-saving aerators that provide flow rates necessary for different household uses. For bathroom faucets, aerators that deliver 2 to 4 L/min of water may be sufficient. Kitchen faucets require a flow rate of 8 to 12 L/min if you regularly fill the sink for washing dishes. On the other hand, if you tend to let the water run while rinsing vegetables, an aerator with a flow rate of about 7 L/min will give good performance and substantial savings. The product packaging for aerators should provide you with flow rate information. Take your old aerator with you to the store to ensure you get the correct size and threading style.
Three people living in a house can use between 110 and 450 L of hot water per day depending on their habits, lifestyle and water use devices. Installing a few simple devices and changing a few habits can really make a difference in your consumption of hot water!
· Get the right capacity tank for your family’s needs. Too much capacity will cost more to purchase and operate.
· If your water heater is approaching the end of its expected service life, research now to determine your best options.
· Remember the second price tag. The operating costs will be greater than the purchase or rental price. Use local energy prices and consider future energy prices in your analysis.
· Compare efficiency ratings. For gas-fired and propane water heaters, look for an ENERGY STAR qualified model. For electric water heaters, look for a lower standby loss.
· Ensure that heat traps and pipe insulation are installed. Where practical, locate the water heater as close to the major uses as possible.
· Consider adding a DWHR device at the same time as you replace your water heater.
· Key points for reducing hot water costs:
· Install low-flow shower heads and faucet aerators.
· Think about how your family uses hot water and take steps to reduce your consumption.
· Use cold water to wash clothes.
· Choose clothes washers and dishwashers that are ENERGY STAR qualified.
- Hot water use is the second largest portion of energy utility costs, after home heating.
- Water heating represents 15 to 25 percent of your household energy bill and may become a larger portion if you upgrade the energy efficiency of your home and its space heating and cooling systems without upgrading your water heating system.
You can reduce your energy bill by
- installing a more efficient water heater
- improving the performance of your existing water heater
- reducing the amount of hot water that you and your family use
- installing a drain water heat recovery (DWHR) device to reduce your water heating load
• No standing pilot as in traditional tank systems. Saves energy by operating only when needed.
• Compact, wall-mounted unit saves space.
• Available in indoor or outdoor designs.
• Life expectancy of twenty years (up to twice as long as tank units).
• Replaceable parts can extend the life of the unit.
• Built-in redundancy with multiunit systems that will keep your facility up and running even if a unit should fail.
• High initial purchase price of around $1500/unit installed.
• Limited flow rate requires multiple units for most foodservice applications.
• Replacement parts may not be readily available in remote areas.
Q. How do these appliances work?
A. Tankless water heaters can be installed to deliver hot water to single or multiuse points. When hot water is called for, cold water flows into the appliance’s copper heat exchanger where it is heated by a gas burner (or if electric, electric elements). Unlike conventional water heaters that operate at a constant input rate, most gas units operate with modulating burners. This
means the gas burners
Q. Does it cost less to heat water with a tankless water heater?
A. Generally, yes. But that all depends on what type of water heating system you’re comparing it to. A standard gas-fired tank-type system has an efficiency rating of between 60 - 70% compared to the 80%+ of tankless units. Here the savings can be significant. But when comparing a tankless unit to that of a high-efficiency condensing-type water heater with an efficiency
rating of 95%+, the actual “fluctuate” from low- to high-fire, depending on the amount of water flowing into the unit. This can save energy and also increase the life of the unit by not overworking it unnecessarily. It only operates when you turn the faucet on.
Q. What is the difference between a tank- type and a tankless water heater?
A. As the name implies, a tankless water heater has no storage tank, but is designed to deliver a “continuous” supply of hot water on-demand up to its maximum rated output. In most foodservice applications, multiple units are necessary to meet energy savings may never be noticed. The big advantage though is that a tankless unit only operates when you need it to, thus eliminating any potential standby loss keeping water hot in a tank.
Q. How much do tankless water heaters cost?
A. One must take into account the first cost, including the cost of the installation. The initial cost of buying a tankless unit or system is usually higher than a tank-type unit. Installation costs of tankless units may be higher or lower than tank- type units; it depends on your particular situation, as there are a number of the required hot water demand. A tank-type water heater is designed to handle large peak demands from multiple fixtures, which is the usage pattern for most restaurants; i.e. warewashing, restrooms, general purpose, cleaning, etc., all of which may operate simultaneously.
Q. Are tankless water heaters more efficient than conventional tank units?
A. Absolutely. There are many brands available on the market today with energy efficiency ratings greater than 80% as reported in the Gas Appliance factors that make up the installation costs.
Q. Can a tankless unit meet the entire hot water demand of my restaurant?
A. Typically, yes. However one must consider the following variables:
• The flow rate through the unit in gallons/minute.
• The minimum and maximum BTUs of the unit.
• The supply water temperature and the temperature rise necessary to heat the water to the required health department temperatures.
The maximum hourly hot water demand and usage pattern of your restaurant will determine how many units you will need. Depending on the brand and model, multiple units can be installed together as a system which can increase the output to fulfill your hot water needs. Just remember, the higher the temperature rise required, the more units you’ll need.
Q. Do tankless units really save space?
A. Yes, they are considerably smaller since they have no tank and are designed to be wall-mounted, inside or out. And in many applications, you may find them even installed on the roof.
It is a tool that serves heat water for household needs without us having to hold them into a tank. as we know, in the winter we need a lot of warm water for everyday purposes. Advantages derived from the tankless water heater is, we can save space because we do not need a tank that big enough as a water reservoir, we can save energy because we only need to heat the water when we need it. and the last one we can save our money.
Base on the sources of energy used, water heater is generally divided into two, namely the use of electricity and gas energy sources. Here's a brief review of the tankless water heater may be to your benefit. the next post we present various kinds of brand tankless water heater that can be a reference for you before buying.