Most water heaters sit in basements. Silent. Bulky. Heating water even when you don’t need it.
Tankless water heaters don’t.
They wait. Then act.
No storage. No standby. Just hot water on demand.
If you’ve ever run out of hot water mid-shower, this might be your fix. This guide breaks down how these heaters work, what makes them energy efficient, and whether they’re right for your home.
Key Takeaways
- Tankless water heaters heat water only when you need it
- They don’t store water like traditional tanks
- Gas and electric models are both available
- They save energy by avoiding standby heat loss
- Ideal for homes with consistent but not excessive hot water demand
What Is a Tankless Water Heater?
A tankless water heater is also called an on-demand or demand water heater.
It doesn’t store water.
It heats cold water only when it flows through the system. That’s the core difference from tank water heaters, which store and heat water constantly.
There are a few common types:
- Inline water heaters: Mounted directly on the water line
- Continuous hot water systems: Provide hot water for extended periods
- Instant or instantaneous heaters: Activate immediately when you turn on the tap
Each does one job: heat water, fast, and only when asked.
How Tankless Water Heaters Work
Step one: You turn on the hot water tap.
Step two: Cold water flows through the unit.
Step three: A gas burner or electric heating exchanger element activates.
It heats the water instantly—no delay, no storage.
The flow rate is usually between 2 and 5 gallons per minute. That’s enough for a shower or a dishwasher. Maybe not both.
The system shuts off when you turn the tap off. Nothing runs in the background. No wasted energy.
Benefits of Tankless Water Heaters
Tankless systems are small. Powerful. Efficient.
- Endless supply of hot water
- Mounts on a wall—saves space
- Better control over water temperature
- No standby heat loss = real energy savings
- Lifespan of 20–35 years with regular care
Potential Drawbacks of Tankless Water Heaters
No system is perfect.
Here’s what to watch for:
- Higher upfront cost than storage water heaters
- Limited flow per unit—may need more than one for large homes
- Performance can dip in cold climates
- Units may struggle if multiple taps run at once
- Self-modulating features help adjust for colder incoming water, but not all models have them
Key Considerations When Selecting a Tankless Water Heater
Before you buy, think:
- Size – Match output to household demand
- Fuel type – Gas or electric availability matters
- Efficiency – Look for the energy factor or UEF rating
- Total cost – Include installation and long-term savings
Gas vs. Electric Tankless Water Heaters
Gas tankless water heaters bring higher flow rates and faster heating. They’re better for big households. But they cost more upfront and often need ventilation. Some keep a pilot light burning.
Electric tankless water heaters are compact and low-maintenance. They’re easier to install but may not keep up with high demand.
Gas or electric, it depends on what you already use and how much water you need.
Tankless vs. Traditional Water Heaters
Storage water heaters heat water 24/7. That’s wasteful.
Tankless units only heat when you turn on the tap.
Long-term? Tankless models use less energy. They cost more at first, but they pay off. Especially if your household uses water in shorter, spread-out bursts.
Intermittent ignition devices (IID) on modern gas units also help cut down wasted energy.
Long-Term Value of Tankless Water Heaters
Yes, they cost more upfront.
But here’s what you get:
- Lower monthly energy bills
- Fewer repairs
- 20+ years of reliable performance
- Smaller carbon footprint
It adds up.
Importance of Professional Installation and Maintenance
Install it right, or it won’t work right.
Here are some variables to consider:
- Fuel type
- Local building codes
- Climate
- Ventilation and safety
Gas systems especially need expert handling. Don’t go DIY unless you’ve read everything and checked your local code.
Once it’s in, maintain it. That means flushing the system and checking filters. Calling a pro once a year for routine maintenance is smart.
Thinking About Upgrading to a Tankless Water Heater?
Live in Everett, WA? So do we.
At Apollo Plumbing, we install both tankless and traditional water heaters. We do repairs and handle maintenance.
We’re the Ready Right Now Plumbers. Got hot water problems? We’re already on it.
FAQs
Thinking about tankless? Here are answers to the most common questions we hear.
Do tankless water heaters really save money?
Yes. You don’t pay to keep 40+ gallons of water hot all day. That’s where the savings kick in.
Can they run out of hot water?
Not really. As long as water flows and energy is available, they keep going. But the flow rate limits how much can run at once.
What size do I need?
Depends on how many fixtures you want to run at once. A small home needs one unit. Bigger homes may need two.
How long do tankless water heaters last?
With proper care, 20–35 years is common.
Can I install it myself?
Technically? Maybe. Should you? No. You’ll want it done safely, especially with gas lines.
Do they work in cold climates?
Yes, but performance can drop. Look for models with cold-weather protection or self-modulation.
Final Thoughts
A tankless water heater isn’t for everyone. But if you want lower bills, more space, and endless hot water—it’s worth a look.
Live near Everett?
Apollo Plumbing can help you decide. Call the Ready Right Now Plumbers today.
