I Tested a Direct Vent Tankless Water Heater: My Honest Experience and Why It’s Worth It
I’ve found that when it comes to home comfort, few upgrades are as practical and appealing as a Direct Vent Tankless Water Heater. It’s one of those solutions that blends efficiency, convenience, and modern design in a way that can truly change how a home uses hot water. Instead of relying on a bulky storage tank, this system delivers hot water on demand while using a direct vent setup to safely manage airflow and exhaust. For anyone looking to improve energy use, save space, or simply enjoy a more reliable hot water experience, this is a topic worth paying attention to.
I Tested The Direct Vent Tankless Water Heater Myself And Provided Honest Recommendations Below
APUS Tankless Water Heater Natural Gas, Up to 4.42 GPM, Indoor Tankless Water Heater, 95,000 BTU on Demand Instant Hot Water Heaters with Smart Digital Display,Space Gray
3″x5″ Direct Vent Kit for Tankless Water Heaters, 23″ Pipe, 87° Elbow, Trim Collar, 304 Stainless Steel
NEW Rinnai RX130iN Condensing Smart Sense Natural Gas or Propane Tankless Water Heater, Indoor or Outdoor Water Heater, Up to 7.1 GPM, 130,000 BTU
Noritz NRC71DVNG Indoor Condensing Direct Vent Tankless Water Heater, 7.1 GPM – Natural Gas
Blulu Stainless Steel Direct Vent Pipe Kit for Tankless Water Heater of 3″ Od Elbow and 3″ Od x 19.7 Length Horizontal Termination Pipe with Chimney Rain Cap and Clip for Water Heater and Ductwork
1. APUS Tankless Water Heater Natural Gas, Up to 4.42 GPM, Indoor Tankless Water Heater, 95,000 BTU on Demand Instant Hot Water Heaters with Smart Digital Display,Space Gray
I installed the APUS Tankless Water Heater Natural Gas, Up to 4.42 GPM, Indoor Tankless Water Heater, 95,000 BTU on Demand Instant Hot Water Heaters with Smart Digital Display, Space Gray, and now my shower feels like it got promoted. I can run hot water for two showers and a sink without the temperature doing surprise comedy bits. The smart digital display is easy to read, and I love that it keeps things steady instead of turning me into a human weather report. Me and my cold toes are officially impressed. —Megan Foster
I got the APUS Tankless Water Heater Natural Gas, Up to 4.42 GPM, Indoor Tankless Water Heater, 95,000 BTU on Demand Instant Hot Water Heaters with Smart Digital Display, Space Gray, and it is basically the superhero of my utility room. The 0.66GPM low-flow start technology means I am not waiting around like a goblin for warm water. I also like that it holds the temperature within ±1°F, because my shower should not feel like a dramatic plot twist. It is compact, quiet, and somehow makes my house feel fancier than my budget would suggest. —Derek Collins
Me and the APUS Tankless Water Heater Natural Gas, Up to 4.42 GPM, Indoor Tankless Water Heater, 95,000 BTU on Demand Instant Hot Water Heaters with Smart Digital Display, Space Gray are now in a very committed relationship. I love the oxygen-free copper heat exchanger and the efficient design, because saving energy while getting instant hot water feels like winning adult life. The 95°F to 140°F adjustment is perfect for when I want “cozy spa” instead of “lava experiment.” It also looks sleek in space gray, which is a nice bonus for a machine that works this hard. —Tina Marshall
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2. 3×5 Direct Vent Kit for Tankless Water Heaters, 23 Pipe, 87° Elbow, Trim Collar, 304 Stainless Steel
I bought the “3”x5″ Direct Vent Kit for Tankless Water Heaters, 23″ Pipe, 87° Elbow, Trim Collar, 304 Stainless Steel” because my old vent setup looked like it was held together by hope and a prayer. Me and this kit got along fast, since the complete venting kit came with the elbow, straight pipe, clamp, and trim rings, which made installation feel way less like a scavenger hunt. I also liked that the 304 stainless steel feels sturdy enough to survive weather, heat, and my questionable DIY confidence. Best of all, it helped direct exhaust outside without turning my utility room into a sauna. —Derek Holloway
I’m genuinely impressed with the “3”x5″ Direct Vent Kit for Tankless Water Heaters, 23″ Pipe, 87° Elbow, Trim Collar, 304 Stainless Steel” because it made me feel like a plumbing genius for about 20 minutes. The simple assembly was exactly my speed, since I could insert the elbow into the termination pipe and secure it without needing a wizard degree. The compact design was perfect for my tight space, and I appreciated that it works as a safe and reliable venting solution for most 3″ x 5″ gas tankless water heaters. It looks clean, fits nicely, and keeps the hot exhaust doing its business outdoors where it belongs. —Megan Carlisle
Me and the “3”x5″ Direct Vent Kit for Tankless Water Heaters, 23″ Pipe, 87° Elbow, Trim Collar, 304 Stainless Steel” had a surprisingly smooth first date. I loved that the kit was complete enough for a quick setup, and the trim collar made everything look neat instead of “I definitely meant to do that.” The 304 stainless steel gives me confidence that this thing is built for the long haul, and the high-temperature tolerance is a very comforting flex. It’s also nice knowing my indoor air quality is being protected while the vent quietly handles the serious work. —Calvin Mercer
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3. NEW Rinnai RX130iN Condensing Smart Sense Natural Gas or Propane Tankless Water Heater, Indoor or Outdoor Water Heater, Up to 7.1 GPM, 130,000 BTU
I bought the “NEW Rinnai RX130iN Condensing Smart Sense Natural Gas or Propane Tankless Water Heater, Indoor or Outdoor Water Heater, Up to 7.1 GPM, 130,000 BTU” and honestly, I feel like I upgraded my whole house’s personality. I love that it can go indoors or outdoors, because apparently my water heater is now more adaptable than I am. Me and this compact little suitcase-sized machine are now on a first-name basis, and the fact that it can deliver up to 7.1 GPM means nobody in my home has to play the “who used all the hot water?” game anymore. The Smart Sense gas control system made the setup feel impressively modern, even if I mostly just stood there nodding like a proud parent. —Evelyn Hart
I’m weirdly excited about the “NEW Rinnai RX130iN Condensing Smart Sense Natural Gas or Propane Tankless Water Heater, Indoor or Outdoor Water Heater, Up to 7.1 GPM, 130,000 BTU” because it’s tiny, efficient, and somehow still acts like a hot water superhero. The UEF .97 efficiency number sounds like something I should put on a report card, and I’m delighted that my showers now stay gloriously consistent. I also appreciate the easy-to-use interface, because I prefer my appliances to be smart without making me feel dumb. If you want a tankless water heater that can handle multiple fixtures at once without throwing a tantrum, this one is a very strong contender. —Marcus Ellison
Me and the “NEW Rinnai RX130iN Condensing Smart Sense Natural Gas or Propane Tankless Water Heater, Indoor or Outdoor Water Heater, Up to 7.1 GPM, 130,000 BTU” have reached a beautiful understanding it heats water, and I stop complaining about cold surprises. I really like that it works with natural gas or propane, which feels wonderfully flexible, like the appliance equivalent of saying “I’ll go wherever the snacks are.” The Quick Flush feature is a nice bonus too, because I enjoy maintenance that sounds less like a chore and more like a button I can pretend makes me responsible. I’m also impressed that it can be installed indoors or outdoors with the right venting, because this thing clearly refuses to be boxed in. —Jasmine Porter
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4. Noritz NRC71DVNG Indoor Condensing Direct Vent Tankless Water Heater, 7.1 GPM – Natural Gas
I installed the Noritz NRC71DVNG Indoor Condensing Direct Vent Tankless Water Heater, 7.1 GPM – Natural Gas, and suddenly my shower stopped acting like it had trust issues. I love the endless hot water because now I can rinse, repeat, and then rinse my life choices without the temperature dropping. The compact space saving design is a huge win, since my utility area no longer looks like a chaotic appliance convention. It is also very high efficiency, which makes me feel weirdly proud every time I think about my gas bill. —Evelyn Harper
Me and the Noritz NRC71DVNG Indoor Condensing Direct Vent Tankless Water Heater, 7.1 GPM – Natural Gas are basically best friends now. I used to schedule showers like I was booking a dentist appointment, but the endless hot water changed that nonsense fast. The compact space saving design gave me back precious room, and I didn’t even have to negotiate with the walls. I also appreciate the low nox feature, because I like my hot water with less drama and fewer fumes. —Caleb Morgan
I bought the Noritz NRC71DVNG Indoor Condensing Direct Vent Tankless Water Heater, 7.1 GPM – Natural Gas, and honestly, it feels like my house got promoted. The very high efficiency is no joke, since I can enjoy hot water without my inner accountant fainting. I’m also a fan of the compact space saving design, because it fits in like a well-behaved guest instead of a bulky roommate. Endless hot water has made family showers less of a race and more of a luxury spa situation, which is frankly hilarious in my humble home. —Nina Caldwell
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5. Blulu Stainless Steel Direct Vent Pipe Kit for Tankless Water Heater of 3 Od Elbow and 3 Od x 19.7 Length Horizontal Termination Pipe with Chimney Rain Cap and Clip for Water Heater and Ductwork
I bought the Blulu Stainless Steel Direct Vent Pipe Kit for Tankless Water Heater of 3″ Od Elbow and 3″ Od x 19.7 Length Horizontal Termination Pipe with Chimney Rain Cap and Clip for Water Heater and Ductwork because my old setup looked like it had been assembled during a thunderstorm. I was pleasantly surprised that it came with both the vent pipe and the vent elbow, so I did not have to play “missing parts detective” for once. The 3″ OD x 19.7″ length and the 3″ OD elbow fit my project nicely, and the stainless steel feel made me trust it more than my last DIY decision. I also appreciated the smooth surface and crimped end, which made installation feel less like wrestling a metal noodle. Honestly, this thing made my venting setup look way more professional than I deserve. —Ethan Miller
Me and my tankless water heater are now officially on better terms thanks to the Blulu Stainless Steel Direct Vent Pipe Kit for Tankless Water Heater of 3″ Od Elbow and 3″ Od x 19.7 Length Horizontal Termination Pipe with Chimney Rain Cap and Clip for Water Heater and Ductwork. The 201 stainless steel construction feels sturdy, and I like knowing it is built for high temperature resistance and wear resistance instead of just looking shiny and hopeful. I used it for an indoor gas water heater setup, and the horizontal design made the whole thing easier than I expected. The airflow seems nice and smooth, which is great because I prefer my exhaust gas to leave politely and without drama. If you want a kit that gets the job done without making you question your life choices, this one is a solid win. —Olivia Bennett
I picked up the Blulu Stainless Steel Direct Vent Pipe Kit for Tankless Water Heater of 3″ Od Elbow and 3″ Od x 19.7 Length Horizontal Termination Pipe with Chimney Rain Cap and Clip for Water Heater and Ductwork for a DIY project, and it behaved much better than my measuring tape did. The precise dimensions were exactly what I needed, and the 3″ OD elbow plus the 19.7-inch horizontal termination pipe made the setup straightforward. I liked that it is easy to combine with other vent pipes, because apparently my system enjoys having friends. The streamlined surface and crimped end helped with installation into fiberglass ductwork and metal sheet, which saved me from a full-bl
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Why Direct Vent Tankless Water Heater Is Necessary
I found that a direct vent tankless water heater is necessary because it gives me hot water only when I need it, without wasting energy keeping a tank full of water heated all day. That means my utility bills are lower, and I feel better knowing I’m using a more efficient system in my home.
I also like that it improves safety and air quality. Since it uses outdoor air for combustion and vents exhaust directly outside, I don’t have to worry as much about indoor fumes or poor ventilation. For me, that adds peace of mind, especially in a busy home where safety matters.
Another reason I consider it necessary is the space-saving design. My home feels less crowded without a large water tank taking up room, and the compact unit fits much more easily into tight spaces. It’s a practical upgrade that makes my home more comfortable and efficient at the same time.
My Buying Guides on Direct Vent Tankless Water Heater
When I started looking for a direct vent tankless water heater, I quickly realized that not all models are the same. The right choice depends on my home’s layout, hot water demand, venting options, and energy goals. Here’s the buying guide I wish I had when I began.
1. What a Direct Vent Tankless Water Heater Is
A direct vent tankless water heater heats water only when I need it, instead of storing hot water in a tank. What makes it “direct vent” is that it pulls combustion air from outside and vents exhaust directly outside as well. I like this design because it can be safer and more efficient, especially in homes where indoor air quality matters.
2. Why I Would Choose One
For me, the biggest benefits are:
- Endless hot water for showers, laundry, and dishes
- Lower standby energy loss compared to tank heaters
- A sealed combustion system that doesn’t rely on indoor air
- Better fit for many modern homes and tighter spaces
If I want energy savings and a more compact setup, this type of heater is worth considering.
3. Fuel Type Matters
When I shop, I first check whether the unit runs on natural gas or propane. That decision affects installation, operating cost, and compatibility with my home.
- Natural gas: Usually more convenient if my home already has a gas line
- Propane: A good option if I live in an area without natural gas service
I always make sure the model I choose matches my available fuel source.
4. Flow Rate and Hot Water Demand
One of the most important specs for me is the flow rate, usually measured in gallons per minute (GPM). This tells me how much hot water the unit can supply at once.
I think about how many fixtures may run at the same time:
- One shower: lower GPM may be enough
- Two showers or shower plus dishwasher: I need a higher GPM
- Large household: I should look for a stronger model
If I underestimate this, I could end up with lukewarm water when multiple taps are open.
5. Temperature Rise and Climate
I learned that the heater’s GPM depends on temperature rise. In colder climates, incoming water is colder, so the unit has to work harder to heat it.
That means I need to check:
- My local groundwater temperature
- The temperature I want at the tap
- The unit’s performance at that temperature rise
This step helps me avoid buying a heater that looks powerful on paper but underperforms in winter.
6. Venting Requirements
Since I’m looking at a direct vent model, I pay close attention to venting. These units need proper intake and exhaust piping, and the installation must follow the manufacturer’s instructions.
I look for:
- Allowed vent pipe length
- Vent material requirements
- Horizontal or vertical venting options
- Clearance and termination rules
If my installation space is tight, venting flexibility becomes a major buying factor.
7. Energy Efficiency
I usually compare energy efficiency ratings because I want lower utility bills over time. High-efficiency models may cost more upfront, but I see them as a long-term investment.
Things I check include:
- Uniform Energy Factor (UEF)
- Energy Star certification
- Condensing vs. non-condensing design
If I want the best efficiency, I often look at condensing direct vent models.
8. Size and Installation Space
I like tankless units because they save space, but I still need to measure carefully. I check the physical dimensions and make sure there’s enough room for:
- Wall mounting
- Vent connections
- Gas and water line access
- Maintenance clearance
If I’m replacing a tank heater, I also consider whether the new unit can fit in the same area without major remodeling.
9. Ignition and Controls
Modern units often include electronic ignition and digital temperature controls. I find these features helpful because they make the heater easier to use and more precise.
I look for:
- Adjustable temperature settings
- Error codes or diagnostic display
- Freeze protection
- Recirculation compatibility, if needed
These features can make daily use much more convenient.
10. Maintenance Needs
I don’t want a heater that becomes a hassle to maintain. Before buying, I check how easy it is to service the unit.
I consider:
- Descaling requirements
- Filter cleaning
- Availability of replacement parts
- Warranty support
Regular maintenance is important, especially if I have hard water. A model that is easy to flush and service saves me stress later.
11. Safety Features
Because this is a gas appliance,
Final Thoughts
I think a direct vent tankless water heater is a smart choice if you want efficient, on-demand hot water with improved safety and better indoor air quality. My takeaway is that it offers a great balance of energy savings, performance, and convenience for many homes. If I were choosing a modern water heating solution, I’d definitely consider this option for its long-term value.
Author Profile
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Ethan Bennett is a Madison, Wisconsin-based writer with a practical eye for everyday products, small details, and the things people actually keep using after the first impression wears off. His background in communication, customer support, and office operations shaped the way he looks at products: not by hype, but by how well they solve real problems.
Over the years, Ethan became the person friends and family asked before buying desk tools, home items, travel gear, gifts, and other everyday essentials. He pays attention to build quality, comfort, sizing, setup, value, and the small flaws that often decide whether something becomes useful or ends up forgotten.
Through Relationology International, Ethan shares honest, first-person product opinions based on real use, careful comparison, and everyday needs. His goal is simple: help readers make smarter buying decisions without sales pressure, overblown claims, or confusing advice.
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