The Ultimate Smart Hack: Get Instant Hot Water Using a Recirculating Pump and a Smart Plug

It’s one of the most common, frustrating, and wasteful parts of modern life: you turn on the hot water faucet and… you wait.

You wait for the cold water sitting in the pipes to be pushed all the way from the water heater to your sink. As you stand there, you are dumping gallons of clean, fresh water straight down the drain. It’s a waste of water, a waste of energy (if you’re on a well pump), and, most importantly, a waste of your time.

The most common solution for this is a hot water recirculating pump. This is a small pump you install under the faucet farthest from your water heater. It creates a loop that slowly pushes the cold, stagnant water back to the water heater through your cold water line, so your hot water line stays primed and ready.

But here’s the problem: how does the pump know when you want hot water?

This is where “smart” pumps often fail, and where a little bit of DIY tech knowledge can create a system that is infinitely better, cheaper, and more efficient than what’s advertised on the box.

The “Smart Pump” Trap: Why Built-in Modes Are Inefficient

Most recirculating pumps come with “smart” features that, in practice, aren’t very smart.
1. The “Always On” Mode (Smart Mode): This mode uses a thermostat to keep the water in your pipes hot 24/7. It’s convenient, but it’s also terribly inefficient. It’s constantly running the pump and forcing your water heater to fire up all day and night just to heat pipes in your walls, even when you’re asleep or at work.
2. The “Timer” Mode (Energy-Saving Mode): This is slightly better. It lets you set a schedule, like “turn on from 6 AM to 8 AM.” But what about on Saturday when you sleep in? Or when you need to wash your hands at 3 PM? It’s still just a guess.
3. The “Manual/Remote” Mode: Some pumps come with a remote. As several users have noted, these are often confusing, have limited range, and may run the pump for a full hour after you press the button—a massive waste of energy.

There is a better way. The ultimate solution is to buy a “dumb” pump and make it truly smart yourself.

The Ultimate Hack: A “Dumb” Pump + A “Smart” Plug

The perfect on-demand hot water system consists of two simple parts:
1. The “Muscle”: A high-quality, reliable recirculating pump.
2. The “Brain”: A $10 smart plug (like a Wemo, Kasa, or any plug that works with Alexa or Google Home).

By combining these two, you create a system that is truly on-demand. You can activate it with your voice, with a tap on your phone, or even automatically with sensors.

Step 1: Choose Your “Muscle” (The Pump)

You can’t just use any pump for this. You need to find one that has one, absolutely critical feature: a smart memory function.

This means that if the power is cut (by your smart plug) and then restored, the pump will remember its last setting (in this case, “Manual Mode” or “On”).

A perfect example of a pump built for this hack is the PROZRTED HBS24-12. Let’s use it as our case study. While its own “smart modes” can be confusing, its hardware is exactly what we’re looking for: * It “Work[s] well with the smart plug” and has a “Smart memory function,” according to the manufacturer. This is the most important part. * It has an advanced brushless 24V DC motor. This is crucial. It means the pump is extremely quiet (you won’t hear it rattle under the sink) and durable. * It’s NSF Certified and uses a lead-free copper body, which means it’s safe for your drinking water. * It’s powerful, with a high flow rate (6.1 GPM), meaning it gets the hot water to you fast when you command it.

So, you’ll buy this pump, install it, and set its mode to “Manual” or “On.” Then, you plug its 10-foot power cord into your smart plug. The pump is now ready to take orders from its new “brain.”

Step 2: Program Your “Brain” (The Smart Plug Routines)

This is where the magic happens. Now you can create simple, powerful routines that waste zero energy.

Good: The Voice Command
Create a simple Alexa or Google Home routine: * You say: “Alexa, turn on the hot water.” * Alexa does:
1. Turns on the “Recirculating Pump” (your smart plug).
2. Waits 2-3 minutes (the time it takes to prime the line).
3. Turns off the “Recirculating Pump” automatically.

Now, you can just ask for hot water as you walk towards the bathroom, and by the time you get there, it’s ready.

Better: The Sensor Command (The “Magic” Hack)
This is what the pro-level user did. * Buy: A cheap smart door sensor (like those used for security systems). * Create an Alexa Routine:
1. When: “Bathroom Door” sensor closes.
2. Alexa does: Turns on the “Recirculating Pump.”
3. Wait: 2 minutes.
4. Action: Turns off the “Recirculating Pump.”

The result? You walk into the bathroom and close the door. You don’t say a word. The pump silently primes the hot water line while you’re washing your hands or getting ready to shower. By the time you turn the tap, the hot water is instantly there. It’s a completely automated, invisible, and “magical” experience that only runs when you’re in the room and wastes zero energy.

Step 3: The “Mentor’s Warning” — Be Prepared for Plumbing

Now, for the dose of reality. The “brain” part is easy. The “muscle” part involves plumbing, and as one DIYer, “Chuck,” wisely noted, “This is a plumbing device so be prepared for the unexpected.”

The pump (like the HBS24-12) installs under the sink farthest from the water heater. It uses two “T-adapters” to connect to your hot and cold water angle-stop valves and your faucet lines.

Be warned: User reviews for almost all pumps in this category (including this one) are filled with stories of frustration with the included adapters and hoses. * The included hoses may be too short. * Your home’s fittings may be non-standard (like hard plastic lines instead of flexible braided ones). * The included “T-adapters” can be difficult to seal and may leak if not installed perfectly.

The Pro-Tip: Before you start, take a picture of your under-sink plumbing. When you buy your pump, take the included adapters and hoses straight to a hardware store. Show the picture and the parts to an experienced employee in the plumbing aisle and say, “I need to connect this. What else do I need?”

A few extra dollars on a high-quality 20-inch braided supply line or a proper brass 1/2” to 3/8” adapter will be the best money you’ve ever spent. It will save you three trips back to the store and a cabinet full of water.

Conclusion: Stop Waiting, Start Automating

Stop wasting gallons of water every single day. The technology to solve this problem is here, but the smartest solution isn’t the one on the box.

By tossing the confusing built-in timers and remotes, you can build a truly on-demand system. All it takes is a reliable “muscle” pump (like the PROZRTED HBS24-12 that’s built to be quiet and work with smart plugs) and a cheap “brain” (your Alexa or Google Home).

This combination gives you the best of all worlds: the magic of instant hot water, the satisfaction of a clever DIY hack, and the efficiency of a system that only runs when you need it.