On-Demand Hot-Water Recirculating Pump

This article discusses An On-Demand, Hot-Water Recirculating Pump To Provide Hot Water Quickly.  Al’s Plumbing, Heating & A/C, in Plano, Texas provides full-service plumbing maintenance, repairs and replacements for every plumbing component in your home.  Al’s sells and installs Rheem Professional Series gas & electric water heaters, and tankless water heaters.  Al’s Plumbing, Heating & A/C is near your home in Plano, TX; Allen, TX and Frisco, Texas.  We service all homes in southern Collin County, TX and Denton County, TX with no additional travel charge.

How Long Do Your Faucets Run Before The Water Gets Hot?

Each year, a family of 5 wastes approximately 13,500 gallons while waiting for hot water,

and pays for both the water — and the sewer fee. **

** Source:http://aquamotionhvac.com/hot-recirculation-systems/

Image Source: ShutterStock

Let’s Convert This To Dollars 

A U.S. government study ** estimates water savings of up:

• 12,000 gallons for 4 hot water use locations
• 15,000 gallons for 5 hot water use locations.  This might be; kitchen, laundry room, half bath in hall, and 2 full baths.
• Image the wasted hot water in a home with 4, 5, or 6 bathrooms.

** Source: https://www.pmmag.com/articles/101559-what-you-need-to-know-about-hot-water-recirculation

Another Government study says about 90 gallons of water are used per day — per occupant in a home.   A family of 5 uses 450 gallons a day. This equates to 13,500 gallons per month.

*** https://www.usgs.gov/special-topic/water-science-school/science/water-qa-how-much-water-do-i-use-home-each-day?qt-science_center_objects=0#qt-science_center_objects

Plano, TX Charges These Rates Per 1,000 Gallons Of Water:

$ / 1,000 Gallons                  Total Monthly Water Use **2

• $3.75                               5,001 — 20,000 per month

• Sewer Rate: $6.00 / 1,ooo Gallons

** 2: https://ecop.plano.gov/cus/Rates

If a family of five wastes 15,000 gallons of water per year waiting for it to get hot — the cost of that wasted water (& sewer charge) is:

• Water + Sewer charge = $9.75 per 1,000 gallons.
• X 15,000 gallons.
• TOTAL = $145.00 per year

• Angie’s List **3 states the cost for an on-demand water-recirculating pump cost: “$300-600 — depending on pump model.”

**3: https://ecop.plano.gov/cus/Rates

In Plano, TX — A Whole-House, Hot-Water Recirculating Pump (installed) Will Pay For Itself In Around 3 Years.

Can The Amount Of Wasted Water Vary By Home?

Image Source: Shutterstock

Image Source: Shutterstock

Yes, it depends on two things:

• How close (or how far) fixtures are from the water heater.  The larger the home, the farther some fixtures are.

• The diameter of the water pipes.

Homes have different diameter water pipes.  For Example:  As compared to a 2 bath home — a 4 bath home has larger diameter pipes.  This ensures that all four baths can run at once — and all will have enough water pressure.

Which holds more water?

• A 4″diameter BY 12″ tall water pitcher.
• An 6″ diameter BY 12″ tall water pitcher.

Just like the larger diameter water pitcher,  the larger diameter a home’s pipes are — the more water they hold.  With larger diameter pipes,  you get hot water faster — but at the cost of more water being wasted.

Can The Amount Of Wasted Water Vary By The Home’s Location?

Yes, the farther north you live, the colder the winters are.

• Hot water sitting in water pipes loses its heat faster during colder outdoor temps.
• Once the heat in the water is gone — the pipes also get colder during colder outdoor temps.

Today, Some Building Codes Dictate That A Newly Built Home Must Have A Recirculating Pump.

Note:

• Texas Building Codes adopt the International Residential Code 2015 (IRC 2015).  ****

• Not all locations’ Building Codes match or exceed IRC (International Residential Code).

**** Source: https://up.codes/codes/texas

How Does An On-Demand, Hot-Water Recirculating Pump Work?

• These pumps are connected to both the hot water and cold water. 

When The On-Demand Hot Water Recirculating Pump Is Activated

• It pumps hot water FROM the water heater to the fixture.

• It returns cold water (sitting in the hot water line) TO the water heater — using the existing cold water line. 
• Note: Some homes do have an additional, dedicated water-return line.

• Many recirculating pumps don’t require a separate water return line.
• These pumps require a “Double-Tee Bypass Valve” — that links the hot and cold water pipes together.
• This allows hot water to come to the fixture while pushing cold water (inside the pipes) from the fixture toward the water heater.

The On-Demand, Hot Water Recirculating Pump can be activated in several ways:

• Push a button.
• Open a faucet for 1 second.
• A motion-sensor as you enter the room.
• There may be other activating methods unique to specific pumps.

There Are Two Different Types Of On Demand Hot Water Recirculating Pumps:

• Whole-House (for copper water pipes)
• Single-Fixture (for copper or PEX water pipes)

While it may seem odd to install a Single-Fixture versus a Whole-House Pump — the type of pump(s) required depends on:

• The type of water pipes your home has — Copper Or PEX
• Where the fixture(s) are located — in relation to water heater.

Copper Water Pipes

• If your home has Copper water pipes — A Whole-House Pump OR Single-Fixture Pump(s) can be used.
• This is because copper water pipes are typically installed in a: “Trunk & Branch” Configuration.

This means:

• There is one main (trunk) water line that serves all fixtures.
• Each fixture is connected to the main water line — using a smaller (branch) water pipe.
• Because all fixtures’ are connected to one main — 1 Whole-House Recirculating Pump will work.

Image Source: Shuttestock

Shown: The Horizontal Pipe Is The Main / Trunk Pipe.  Vertical Pipe Is A Single-Fixture (Branch) Water Pipe.

That said, it may be best to install single-fixture pumps with copper pipes.

• If the most used fixtures are near to the water heater — there’s no need to heat the entire main / trunk water line.

• It’s better to install a single-fixture pump.  That way, the main water line is heated only as far as that fixture. 

PEX Water Pipes   

Image Source: Shutterstock

Shown: PEX water pipes in an attic installation (attic installations are only for the southern U.S.).

Click Here To Learn All About PEX Water Pipes: AlsPlumbing.com PEX Water Pipes

• Most homes built since the mid 1980’s have PEX Water Pipes.   

• PEX stands for: Cross-Linked Polyethelene.  It’s a Flexible Water Pipe made from a Polymer (a heavy-duty type of plastic). 

• With PEX — each fixture has its own separate water pipes.

• All fixture are connected to one PEX Manifold.  It’s located near the water heater.

Image Source: Shutterstock

Shown: PEX Manifold.  Red = hot and Blue = cold water pipe.

• Because PEX has separate pipes for each fixture — each fixture must have its own water-recirculating pump.

• You don’t have to install a pump at each fixture.  You can chose which fixture(s) you want fast hot water to.

• The On Demand Hot Water Recirculating pump is installed in the cabinet below sinks (kitchen and bath).

In An Existing Home With PEX Water Pipes,

Installing A Recirculation Pump At A Bathtub Or Shower Gets Complicated.

• With sinks, there’s easy access to the plumbing, and a place for the recirculating pump to go.

• With bathtubs / showers, you don’t have either.

• Because of this, it’s likely best to install a pump when the bathtub / shower when the faucet is replaced.

• This is because the wall will likely have to be opened to gain access to the faucet.

• But there’s still an issue about where the pump can go.

• This depends on a bathroom’s configuration — and adding a pump may not be feasible if there’s no place to put it.

• With Copper Pipes — your bath vanity likely connects to the main water line near where the bathtub / shower does.  Using its pump will bring hot water close to your bathtub / shower.

On-Demand Versus Constant Hot Water Recirculating 

Early versions of hot-water recirculating pumps ran all the time.  This wastes a lot of energy by keeping water lines hot 24/7. There’s no benefit in having this type of pump versus On-Demand.  To keep an entire copper hot water line heated all the time creates notable additional energy bills.  Copper cools off fast, and the released heat is seldom usable by the home.

In homes with basements, the majority of water pipes are in the basement or inside walls.   For slab homes, the pipes are under the slab and come (through the slab) into living space at each fixture’s location.  In either case, the released heat (from the water pipes) does little to help heat the home.

When activated, On-Demand begins exchanging cool water (in the hot water lines) with hot water (from the water heater).  It takes the on-demand pump less, or about the same amount of time to bring hot water to the fixture as running the cool water down the drain.

Click Here For A Brief Article From Bob Vila Of The “This Old House” Show: Hot Water Recirculating Pumps

Another Potential Solution — Instead Of A Hot-Water Recirculating Pump

Quite small, under sink, electric water heaters can provide instant hot water.  They are standard, 120-Volt Operation, so no special electric wiring is required.

If you have one or two sinks that are a long way from the water heater — you have to heat long water lined before hot water reaches that location.  If these sink(s) are used frequently, it’d likely more energy efficient to install a mini water heater in the sinks cabinet.

The recirculating pump doesn’t waste water, but requires all the water (sitting in the pipe) — be returned to the water heater for reheating.  For distant fixtures, the “stand-by heat loss” (hot water in the pipe getting cold again) — may be higher with the recirculating pump than with a mini water heater.  This cost is magnified if you have an electric (versus gas) home water heater.

If you have frequent, small needs for hot water at at a distant fixture — mini water heaters are available in 1–2.5 gallon size.  This water heater connects to the existing hot water pipe — and to the existing cold water pipe (no new pipes are needed).  Then the water comes from the heater to the faucet.  It will deliver hot water within a second — much faster than a recirculating pump at a distant fixture.

Image Source: Amazon.com Embedded Link

Shown: 2.5 Gallon, Standard 120-Volt, Electric Water Heater

Click On Image To; View Product, Read Details, or Purchase From Amazon.com

This article was about On-Demand, Hot-Water Recirculating Pumps To Provide Hot Water Quickly.  Al’s Plumbing, Heating & A/C, in Plano, Texas provides full-service plumbing maintenance, repairs and replacements for every plumbing component in your home.  Al’s sells and installs Rheem Professional Series gas & electric water heaters, and tankless water heaters.  Al’s Plumbing, Heating & A/C is near your home in Plano, TX; Allen, TX and Frisco, Texas.  We service all homes in southern Collin County, TX and Denton County, TX with no additional travel charge.