Answering What is a Point of Use Water Heater
Need an on-demand supply of hot water without wasting energy heating water you don't use? Point of use water heaters provide a targeted solution.
These compact units deliver hot water right where and when you need it. Continue reading to learn what point of use water heaters are, how they work, the pros and cons, and whether one is right for your situation.
Definition of a Point of Use Water Heater
A point of use (POU) water heater is a small unit installed close to water outlets like sinks or showerheads to heat water on demand. It provides hot water by boosting the temperature of cold water from main lines right before it exits fixtures. So instead of maintaining a tank of hot water ready for any use, it heats water only when needed.
Key Features
- Compact size - Roughly the dimensions of a small suitcase or under sink cabinet.
- On demand heating - Activates to heat water only when hot water is required.
- Fast heating - Delivers hot water in seconds or minutes by rapidly heating a small amount of water.
- Installs at point of use - Mounts on a wall or under sinks closest to water outlets.
By installing right at the tap, POU heaters avoid risks like heat loss over long pipe distances or water cooling off before reaching fixtures far from a central heater. Their small size also allows mounting in confined spaces near sinks or showers.
Types of Point of Use Water Heaters
These on demand water heating systems come in electric and gas-powered varieties. Within those categories exist tankless and small tank models.
Electric
Electric point of use heaters use heating elements to rapidly raise cold water temperature. They plug into a 120V household outlet.
- Tankless - Heat water as it flows through electronics.
- Small tank - Store a small (2-20 gallon) tank of hot water for increased capacity.
Gas
Gas POU heaters need a fuel source like natural gas, propane, or butane. Heat exchangers transfer heat from burning fuel into a stream of cold water.
- Tankless - Ignite burners to instantly heat flowing water.
- Small tank - Use pilot light to keep a small stored amount of water constantly hot.
Advantages of Point of Use Water Heaters
Why install point of use instead of a conventional central heater? They offer unique benefits:
Compact Size
Ranging from the dimensions of a toaster to a small suitcase, their tiny footprint fits in tight spaces. Mount them out of sight but close to sinks, showers or appliances.
Energy Efficiency
Heating only the water needed cuts waste. Electric types use less energy than heating extra water in a storage tank. No standby heat loss from hot water cooling in pipes before reaching fixtures far from a central heater.
Reduced Operating Costs
Using less energy than conventional water heaters cuts electric, gas and propane bills. Lower upfront costs than whole home tankless systems. Save on heating fuel by customizing models to each living space's needs.
Disadvantages of Point of Use Water Heaters
Consider a few downsides too:
Limited Hot Water Capacity
Best suited for sinks, one showerhead or low volume uses. Tankless heat as needed but output maximal 1-5 gallons per minute. Small tank types store extra hot water but tanks still only 2-20 gallons.
Higher Upfront Costs
Pricier than conventional central heaters. Installation also costs more for electrical, fuel line and venting needs. Save over time from lower energy bills.
Ideal Uses for Point of Use Water Heaters
Are they right for your home or business? Best for light duty water heating:
Remote Locations
Avoid running long pipes from a central heater. Install under counters or on walls near standalone sinks and showers.
Single Fixtures
Heat water for one sink, shower or appliance instead of a whole building's plumbing.
Supplementary Heating
Boost temperatures from a central heater that doesn't get hot enough. Help in distant rooms or fixtures with cool water.
How Point of Use Water Heaters Work
These on demand water heating systems use electric or gas power to rapidly boost cold water to desired hot temperatures.
Electric types use heating elements like resistors that get hot when electricity flows through. Burning propane or natural gas transfers heat from flames across metal surfaces inside gas fueled heaters.
Temperature Regulation
A thermostat and sensors measure outgoing water temperature to modulate heating elements or gas flames. This maintains a constant output temperature.
Installation Considerations
Proper mounting accommodates spatial constraints and meets fuel, venting and electric codes. Most electric models just need a 120V outlet while gas types require professional fuel line and flue connections.
Unanswered Concepts
While point of use water heaters provide targeted hot water, many questions remain about optimizing their performance across situations. Here are some open areas for additional research:
Impact of Location on Performance
Ambient environmental temperatures likely affect heating efficiency. Models suited for warm climates may require insulation or backup heat sources to maintain output temperatures in cold weather. Comparing electricity or gas consumption rates across regions could better define system specifications and installation considerations tailored to local climate conditions.
Cost Efficiency in RVs vs Homes
These units are popular for heating limited water supplies in RVs. But operating costs may differ from stationary home applications. Research could analyze upfront purchase and lifetime maintenance costs for units installed in RVs versus under household sinks. Finding the break-even duration for energy savings from each setup would help travelers and homeowners select the most economical option.
Point of use water heaters promise increased efficiency over tank models by heating only water needed. But comprehensive life cycle assessments are lacking. Studies comparing greenhouse gas emissions from manufacturing, power consumption, and disposal between point of use and tank heaters could quantify the real environmental impacts. If scaled globally, determining the technology with lower carbon footprint could guide sustainable product development and consumer purchase decisions.
By providing hot water right where needed, point of use water heaters can reduce energy usage and cut costs compared to central heaters. Evaluate your hot water usage patterns and needs to decide if installing this targeted system makes sense.