Having hot water instantly available at the sink is a modern convenience many homeowners take for granted. But point-of-use hot water systems provide a number of benefits compared to traditional water heater setups. In this article, we’ll explore the advantages of point-of-use hot water and help you determine if it could be right for your home.
Page Contents
- 1 What is Point-of-Use Hot Water?
- 2 How Point-of-Use Hot Water Systems Work
- 3 Benefits of Point-of-Use Hot Water Systems
- 4 Disadvantages of Point-of-Use Systems
- 5 Is Point-of-Use Water Heating Right for You?
- 6 Types of Point-of-Use Water Heaters
- 7 Installation Tips for Point-of-Use Water Heaters
- 8 Maintaining Your Point-of-Use Water Heater
- 9 Conclusion
What is Point-of-Use Hot Water?
Point-of-use (POU) hot water systems deliver instant hot water directly to the faucet or fixture where it’s needed. Instead of relying on a central water heater that heats a large reservoir of water, POU systems use small electric or gas water heaters installed at strategic locations.
For example, a common POU application is an under-sink water heater that provides hot water instantly to just the kitchen sink. Other popular spots for POU heaters include master bathroom sinks, remote guest baths, wet bars, etc. They heat water directly at the point of use rather than heating all household water at a central tank.
How Point-of-Use Hot Water Systems Work
POU hot water systems work by sensing when hot water is needed and immediately heating a small amount of water on demand. Tankless POU heaters pass incoming cold water across heating elements to rapidly raise the temperature. Tank-style POU heaters hold a small reservoir of water hot and ready when needed.
POU heaters are compact, ranging from the size of a small suitcase to not much larger than a dictionary. They can be plugged into a standard outlet or hardwired into the electrical system. Gas tankless POU heaters are also available. The main components are:
- Cold water inlet – Connects to the home’s main cold water line
- Heating element or burner – Electric or gas burner that heats the water instantly
- Hot water outlet – Delivers heated water to the faucet
- Electronic controls – Sense water flow and activate the burner as needed
When the faucet is turned on, a flow sensor tells the POU heater to fire up. Water passes across the heating element and hot water flows from the faucet. POU systems only heat the small amount of water needed on demand rather than maintaining a large volume hot at all times.
Benefits of Point-of-Use Hot Water Systems
Installing POU hot water at sinks, showers and other fixtures provides several advantages:
Faster Hot Water Delivery
One of the biggest benefits of POU systems is instant access to hot water. There’s no waiting for hot water to travel from a distant central heater through long pipes. POU systems eliminate frustratingly long waits for hot water.
Increased Efficiency
POU heaters only fire up when hot water is needed and they only heat the amount required. You don’t pay to constantly maintain a 40- or 50-gallon tank of hot water. This on-demand operation saves energy and money.
Precise Temperature Control
With POU systems, fixtures get the right temperature water needed. For example, a under-sink heater can deliver hot tap water at 120°F-140°F to the kitchen while a master bath POU supplies 105°F water for comfortable showers.
Lower Operation Costs
Because they heat less water and activate only on demand, POU heaters use less energy than central heaters. POU systems are up to 25% more energy efficient. This saves on electricity, gas or propane.
Better Water Conservation
POU heaters reduce water waste in two ways. First, you don’t have to run taps waiting for hot water. Second, there’s no need to drain several gallons of cool water from pipes before it gets hot.
Reduced Scale Buildup
Localized heating helps reduce lime and mineral scale accumulation in pipes and fixtures. This saves on cleaning and descaling maintenance. Less scale also improves operation and lifespan of POU heaters.
Compact Size
The small size of POU systems allows installing hot water exactly where it’s needed. No space is wasted heating water at a central location that then cools off traveling through the building.
Zoned Hot Water
POU heaters let you setup hot water zones to match needs. For example, kitchen hot water can be hotter than bathing areas. Different zones can be set at different temperatures.
Flexible Installation
Compact POU heaters can be installed almost anywhere hot water is needed. No separate boiler room or major plumbing runs required. Common locations include under sinks, in bathroom vanities, under showers and near remote fixtures.
Disadvantages of Point-of-Use Systems
Despite their many benefits, POU hot water systems aren’t perfect for every home. Consider these potential downsides before choosing POU:
- Higher Upfront Cost – Installing multiple POU heaters costs more initially versus one central water heater.
- Limited Flow – Smaller POU heaters have lower flow rates than large central heaters.
- Maintenance – Each POU unit must be maintained versus one central system.
- Space Requirements – Finding space to install POU units can be challenging in some homes.
- Temperature Fluctuations – POU heaters can vary output temps more than central tank heaters.
Is Point-of-Use Water Heating Right for You?
Point-of-use hot water systems offer many advantages but also have some downsides to consider. POU heaters make the most sense for:
- Homes with remote fixtures far from the central water heater
- Home additions where running hot water lines is difficult
- Multi-story homes where distant hot water takes too long
- Kitchens and baths needing instant hot water
- Households wanting higher efficiency and energy savings
For new home construction or remodeling projects, installing POU can be more affordable than extending plumbing for central heaters. Retrofitting POU systems into an existing home can be more costly.
Evaluate your hot water needs and usage to determine if POU heaters are a good solution for all or part of your residence. They provide an efficient way to get hot water exactly where it’s needed, when it’s needed.
Types of Point-of-Use Water Heaters
There are two main categories of point-of-use water heaters: tankless and mini-tank. Let’s look at the pros and cons of each type.
Tankless POU Water Heaters
Tankless POU heaters instantly heat water as it flows through the unit, delivering an unlimited supply of hot water on demand. They don’t store hot water. Advantages include:
- Compact, wall-mounted design
- Truly endless hot water
- Heat water only when needed
- Electric and gas models available
- Easy to adjust temperature
Disadvantages of tankless POU heaters:
- Output temperatures can fluctuate
- Flow rate limits for hot water supply
- Require electrical service of 220-240 volts
- Higher purchase cost
Tankless models work well for low to moderate hot water demand sinks, showers and fixtures. Look for a minimum flow rate of 1.5 gpm at a 45°F temperature rise. Higher flow units are available. Tankless POU heaters range from about $250 up to $1000.
Mini-Tank POU Heaters
Mini-tank POU systems store a small volume of hot water ready for use. A compact tank about the size of a large dictionary is paired with heating elements. When hot water is drawn, cold water enters and is heated. Benefits include:
- Simple, inexpensive option
- Small size installs almost anywhere
- 120V plug-in or hardwired models
- Fast hot water delivery
- 2-5 gallon tanks standard
Disadvantages of mini-tank POU heaters:
- Limited hot water capacity
- Cycle on/off frequently during heavy use
- Storage tank susceptible to scale buildup
- Relies on electricity
Mini-tank POU heaters work well for hand washing and low-flow sinks. Look for 2.5+ gallon units with at least 1500 watt elements for the best performance. Mini-tank POU heaters start around $150-$200.
Installation Tips for Point-of-Use Water Heaters
Proper installation is key to getting the best performance and longevity from POU water heating systems. Follow these tips when installing POU heaters:
- Choose an appropriate location with adequate space for the heater and connections.
- Follow all local plumbing codes for permits, valves, supply lines, etc.
- Dedicate a 20 amp electrical circuit for hardwired tankless POU units.
- Verify adequate inlet water pressure and volume for the POU heater.
- Install a backflow preventer on the cold water inlet as required.
- Insulate hot water lines from POU heater to fixtures.
- Install a pressure regulator if water pressure exceeds manufacturers limit.
- Program temperature settings and configure control module or thermostat.
- Flush and disinfect unit per manufacturer instructions before using.
Careful planning of the best location will ensure your POU heater performs as expected. Follow all installation guidelines to provide years of hot water service. Consider having your POU system professionally installed.
Maintaining Your Point-of-Use Water Heater
Like any water heater, POU systems need periodic maintenance to keep operating efficiently and safely. Follow the manufacturer’s recommendations, but in general:
- Inspect electrical connections annually. Tighten if loose.
- Check water and gas connections for leaks.
- Clean mini-tank interiors yearly to reduce sediment buildup.
- Flush tankless heaters annually to remove mineral scale.
- Clean or replace inlet water supply filter screens.
- Check burner operation and ignition on gas POU heaters.
- Have gas POU heaters serviced by a professional yearly.
Mini-tank POU heaters have anodes that corrode sacrificially to protect the tank. Replace anodes every 2-3 years or when significantly worn. Tankless POU units have no anode but scale removal is key to longevity.
With proper installation care and maintenance, point-of-use water heaters can provide decades of reliable service. Performing annual system checks and tuneups will keep your POU units working efficiently.
Conclusion
Point-of-use hot water heaters offer homeowners the luxury of instant hot water wherever it’s needed. By heating water on-demand right at the point of use, POU systems provide faster hot water delivery, increased efficiency, precise temperature control and great flexibility for new and existing homes.
With tankless and mini-tank models available in electric and gas options, there is a POU heater suitable for sinks, showers, wet bars, remote baths and anywhere hot water is needed quickly. By understanding the benefits, costs, installation considerations and maintenance needs, homeowners can determine if point-of-use systems are right for their homes. With the convenience of hot water precisely when and where you need it, POU systems provide a modern alternative to centralized water heating.