When it comes to providing hot water in your home, you have two main options – using a hot water recirculation pump or installing point-of-use water heaters. Both have their pros and cons in terms of convenience, efficiency, and cost. In this comprehensive guide, we’ll look at how recirculation pumps and point-of-use heaters work, compare the key factors to consider, and help you decide which is the better choice for your home.
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How Does a Hot Water Recirculation Pump Work?
A hot water recirculation pump works by circulating water between your home’s water heater and the fixtures that use hot water – usually the faucets and showerheads that are located the furthest from the water heater. Here is a quick rundown of how it works:
- The pump is installed on the hot water line, connecting the water heater to the home’s plumbing system.
- When activated, it pumps water from the hot water piping back to the water heater through a dedicated return line.
- This creates a constant loop, keeping hot water moving through the pipes.
- The return line has a thermostat sensor that triggers the pump to turn on when the temperature of the water drops below a set point, usually around 86°F-104°F.
- By keeping hot water circulating throughout the plumbing system, hot water is always available within a few seconds when you turn on a hot water faucet or shower.
Benefits of a Hot Water Recirculation System
There are several benefits to having a hot water recirculation pump in your home:
- Provides instant hot water: The main benefit is you get hot water right away at any faucet or shower, without having to wait for cold water to clear the pipes first. This makes tasks like washing hands, doing dishes, and showers much more convenient.
- Saves water: By eliminating the need to wait for hot water, recirculation systems can save thousands of gallons of water each year that would otherwise go down the drain as you wait for hot water to arrive.
- Energy efficient: Keeping hot water pipes heated uses less energy than repeatedly re-heating cold water pipes each time you use hot water.
- Simple installation: Recirculation pumps are easy to install, often requiring only connecting to the hot and cold water plumbing with a return line to the water heater.
Drawbacks of Recirculation Pumps
While recirculation systems provide convenience and efficiency, there are some downsides to consider as well:
- Upfront costs: The pump, return piping, and installation can cost $500-$2,000 depending on the complexity of your plumbing system.
- Increased energy usage: Keeping water constantly heated does use more energy overall compared to a standard system.
- Maintenance: Like any circulating pump, recirculation pumps can eventually fail and need replacement. The return line piping can also accumulate scale needing occasional descaling.
How Do Point-of-Use Water Heaters Work?
Point-of-use (POU) water heaters provide hot water at a single fixture or outlet without circulating hot water through the whole plumbing system. Here’s an overview of POU heater operation:
- A small water heater is installed under the sink or near the point of hot water use.
- When the hot water tap is turned on, cold water flows into the POU heater.
- The unit heats the water on demand and dispenses hot water directly to the faucet.
- POU heaters use electric heating elements or burn propane/natural gas for fuel.
- A temperature sensor controls the heating element or gas burner to bring the water to the desired hot temperature.
- Water is heated as needed when you use hot water, rather than keeping the entire plumbing system hot.
Benefits of Point-of-Use Water Heaters
Here are some of the advantages of using point-of-use water heaters:
- Lower operating costs: Only heating water on demand uses less energy than recirculating hot water through the pipes 24/7.
- Less waste: No need to wait for hot water so no water waste waiting for hot water to reach the fixture.
- Compact size: Small units fit under sinks or close to point of use taking up little space.
- Lower upfront cost: POU heaters cost less to purchase and install than full recirculation systems.
- Zoned heating: Heaters can be installed at high demand locations only, rather than the whole home.
Drawbacks of Point-of-Use Water Heaters
There are also some downsides to consider with point-of-use heaters:
- Slow hot water: There is some wait time for units to heat water on demand
- Limited installation locations: Heaters need power/gas connections which may limit where they can be installed.
- Upfront costs: Installing multiple POU heaters for the whole home can get expensive.
- Maintenance: Like any water heater, POU heaters need occasional maintenance and part replacement.
Hot Water Recirculation vs. Point-of-Use: Key Comparison
Now that we’ve looked at how each system works and their pros and cons, let’s directly compare some of the key factors to consider when choosing between recirculation pumps or point-of-use water heaters.
Hot Water Delivery
One of the biggest factors is hot water availability when you turn on the tap. Here is how they compare:
| Recirculation Pump | Point-of-Use Heater | |
|---|---|---|
| Hot water delivery | Instant hot water in seconds | Wait time for on demand heating, usually 15-30 seconds |
Recirculation systems provide instant hot water, while POU heaters have some lag time while heating the water. The wait for POUs is usually not too bad though, just 15-30 seconds in most cases.
Installation and Upfront Costs
| Recirculation Pump | Point-of-Use Heater | |
|---|---|---|
| Installation requirements | Pump, return line to water heater | 120V electric or gas line for fuel |
| Location flexibility | Anywhere in plumbing system | Limited, needs fuel connection |
| Upfront equipment & install cost | $500-$2000 | $200-$1000 per unit |
Recirculation systems require more equipment like the return line, but can be installed anywhere. POU heaters are limited by fuel connections. Installing enough POU heaters for a whole house costs more than a single recirc pump.
Operating Costs
| Recirculation Pump | Point-of-Use Heater | |
|---|---|---|
| Energy use | More, cycling hot water 24/7 | Less, only when used |
| Water waste | Less waiting for hot water | Less waiting for hot water |
| Annual operating costs | $100-$500 | $30-$150 |
Recirculation systems use more energy to keep water hot constantly. POU heaters only heat water on demand, using less energy. Both options waste less water than a standard tank.
Maintenance and Longevity
| Recirculation Pump | Point-of-Use Heater | |
|---|---|---|
| Equipment life expectancy | 10-15 years | 6-10 years |
| Required maintenance | Pump service, descaling pipes | Descaling, anode/element replacement |
Recirculation pumps tend to have a longer service life than POU heaters. But both require periodic maintenance like descaling and part replacement.
Conclusion
When choosing between installing a hot water recirculation pump or going with point-of-use water heaters, there are good arguments for both approaches. Here are some final guidelines on which may be better for your home:
- Recirculation pump pros: Provides instant hot water; less hassle installing one pump vs. multiple POU units; lower lifetime costs in large homes.
- POU pros: Lower purchase costs; more flexibility for partial installs; uses less energy; good for small homes or apartment/condo installs.
- POU cons: Waiting for hot water; limitations on where units can be installed.
- Recirculation cons: Higher initial investment; increased energy use for pumping and keeping water hot.
Ultimately, it’s a matter of your budget, hot water usage patterns, and how quickly you want hot water available. For most homes, a recirculation system provides the best convenience and lowest lifetime costs. But POU heaters work well in certain situations like low-use second baths or small living spaces. Consider your needs and all the factors in this guide to decide if a hot water recirculation system or point-of-use heaters are the best solution for your home.