The RV water heater debate has been simmering for years—pun intended—but it’s really heated up recently as more manufacturers and aftermarket upgraders have embraced tankless technology. On one side, you’ve got the tried-and-true Suburban tank-style water heater that’s been the backbone of RV hot water for decades.
On the other, you’ve got the Girard tankless system that promises unlimited hot water and a completely different approach to how your RV heats water. Both have passionate advocates. Both have legitimate strengths. And which one is right for your rig depends on how you camp, how you use hot water, and how much you’re willing to invest in the upgrade.
I’ve sold, installed, and troubleshot both systems extensively over the years, and I’ve heard the full spectrum of customer experiences—from Girard converts who say they’d never go back to a tank, to Suburban loyalists who argue that simple, proven technology beats innovation every time. This comparison is my honest assessment of both systems based on real-world performance, not spec sheets and marketing claims.
Suburban has been making RV water heaters since before most of us were camping. Their approach is fundamentally conservative: store a fixed volume of water (typically 6 gallons for travel trailers and Class C motorhomes) in an insulated tank, heat it with a propane burner or electric element (or both on dual-fuel models), and deliver it when you open a faucet. The technology is mature, well-understood, and supported by virtually every RV service shop in the country. Parts are widely available and repairs are straightforward.
Girard came into the RV market with a fundamentally different proposition: eliminate the tank entirely. Their tankless water heater heats water on demand as it flows through a heat exchanger. No stored water, no waiting for a tank to heat up, and—in theory—no running out of hot water because you’re not limited by tank capacity. It’s the same technology that’s become popular in residential homes, adapted for the unique demands of an RV environment.
This 42,000 BTU on-demand water heater eliminates the traditional tank entirely. When you open a hot water faucet, water flows through the unit’s heat exchanger and is heated to your desired temperature in seconds. There’s no tank to fill, no recovery time, and no limit on consecutive hot water use. The unit is significantly smaller and lighter than a tank-style heater, freeing up space and reducing weight in your rig.
The Suburban SW6D is a 6-gallon tank-style water heater with direct spark ignition. It stores 6 gallons of water in an insulated, glass-lined tank and heats it with a propane burner. The direct spark ignition eliminates the pilot light, improving fuel efficiency and safety. This is the type of water heater that’s been factory-installed in travel trailers and motorhomes for decades, and it remains the most common water heater type in the RV industry.
The fundamental difference between these two systems affects almost every aspect of how they perform in real-world camping scenarios. Let me walk through the key performance areas where the technology differences matter most.
This is the headline advantage for the Girard tankless system, and it’s a legitimate one. A 6-gallon Suburban heater gives you approximately 6 gallons of hot water before you’re waiting for recovery. In practical terms, that’s one moderate shower—maybe eight to ten minutes of comfortable water temperature before the hot supply starts declining and you’re finishing in lukewarm or cold water. If two people want to shower back-to-back, the second person is either waiting 20–30 minutes for the tank to recover or showering in increasingly cold water.
The Girard eliminates this problem entirely. It heats water continuously as it flows, so you can theoretically shower for as long as your fresh water tank and propane supply hold out. For families, for full-timers who want the residential shower experience, and for anyone who’s tired of the “navy shower” routine of getting wet, turning off the water, soaping up, and rinsing quickly, the tankless advantage is transformative. I’ve had customers tell me the Girard upgrade single-handedly changed their spouse’s attitude toward RV travel.
The Suburban needs time to heat 6 gallons of cold water to usable temperature. With propane, that’s roughly 15–20 minutes from a cold start. With the electric element, it’s 30–45 minutes. With both running simultaneously on dual-fuel models, somewhere in between. This means planning ahead—you need to turn on your water heater well before you want hot water.
The Girard heats water essentially on demand. Open the faucet, wait a few seconds for the burner to ignite and the heat exchanger to reach operating temperature, and hot water starts flowing. There’s no 20-minute wait, no need to plan ahead. Want to wash dishes at 6 AM? Turn on the hot water and it’s there. This immediacy is something you don’t fully appreciate until you’ve lived with it for a while.
However—and this is important—the Girard does have a brief delay as the burner fires and the heat exchanger warms up. It’s not instantaneous like turning on a light switch. Depending on how far the water heater is from the faucet, you might wait 10–20 seconds for truly hot water to reach the tap. This is normal and consistent with residential tankless behavior, but it’s worth mentioning because some buyers expect “instant” and are surprised by even a short delay.
The Suburban burns propane whenever the burner is firing to maintain tank temperature, even when you’re not using hot water. If you leave the water heater on all day, the burner cycles on and off to keep the tank at temperature, consuming propane continuously. This standby consumption is relatively small but adds up over a multi-day camping trip.
The Girard only burns propane when hot water is actively flowing through the unit. No flow, no fire, no fuel consumption. Turn off the faucet and the burner shuts down immediately. This on-demand approach is inherently more fuel-efficient for intermittent use—which is exactly how most RV owners use hot water. You wash dishes for ten minutes, shower for fifteen, and the water heater sits idle for hours between uses. During those idle hours, the Girard uses zero propane while the Suburban uses some to maintain tank temperature.
The Girard’s 42,000 BTU burner does consume propane at a higher rate while actually firing, compared to the Suburban’s burner. But because it only fires during active use, total propane consumption per day is typically lower for the Girard—sometimes significantly lower, depending on your usage patterns.
The Girard is substantially smaller and lighter than the Suburban. Eliminating a 6-gallon insulated steel tank saves considerable weight and frees up space in the water heater compartment. For weight-conscious RV owners—especially those with half-ton trucks towing near their payload limits—every pound matters. The Girard saves roughly 20–30 pounds compared to a full Suburban tank, depending on the model.
Installation of the Girard as a replacement for an existing Suburban is feasible but not trivial. The plumbing connections are different, the exhaust venting is different, and the compartment dimensions may need adaptation. Some RV owners handle the installation themselves, but I generally recommend professional installation for the Girard because the propane and exhaust connections need to be done correctly for safety. An improperly vented tankless water heater is a carbon monoxide risk.
The Suburban, being the factory-standard heater, benefits from standardized mounting dimensions and plumbing connections. Replacing a Suburban with another Suburban is a straightforward swap—same mounting holes, same plumbing connections, same exhaust venting. This is the simplest, fastest water heater replacement possible.
The Girard wins in scenarios where hot water demand is high, continuous, or unpredictable. Families with kids who all want showers after a day at the beach. Full-timers who use their RV kitchen daily for real cooking that requires sustained hot water for washing up. Couples who refuse to take “camping showers” and want a residential hot water experience. And boondockers who need to conserve propane because every BTU matters when you’re off-grid.
The weight and space savings are a meaningful bonus. The propane efficiency under typical intermittent usage patterns is genuine. And the modern appeal of tankless technology resonates with RV owners who are upgrading other systems—LED lighting, lithium batteries, solar panels—and want their water heater to reflect the same forward-thinking approach.
The Suburban wins on simplicity, serviceability, and proven reliability. There are no electronics to fail, no flow sensors to malfunction, and no minimum flow rate requirements to worry about. Turn it on, wait for it to heat up, and use it. Every RV service shop in the country knows how to repair a Suburban water heater. Parts are available at any RV supply store and most big-box hardware stores. If something breaks on the road, you can get it fixed almost anywhere.
The Suburban is also the better choice for RV owners in extremely cold climates where the water heater tank serves a dual purpose. Some RVers in cold weather leave the water heater running continuously as a form of freeze prevention—the warm tank helps keep the water heater compartment above freezing, which protects the surrounding plumbing. The Girard has no tank and doesn’t provide this ambient heat benefit.
Cost is another significant factor. The Suburban is considerably less expensive than the Girard, both in initial purchase price and installation cost. If your current water heater has failed and you need a replacement, a Suburban swap can be done in a couple of hours for a fraction of the cost of converting to tankless. The economics of the Girard only pencil out if you value the performance benefits enough to justify the higher investment.
Finally, the Suburban operates with zero minimum flow rate. It doesn’t care how slowly you run the hot water faucet—the water in the tank is already hot. The Girard requires a minimum flow rate to activate the burner, which means a very slow trickle from the faucet won’t trigger the heater. This is rarely a practical issue, but it’s worth knowing about.
The choice between Girard and Suburban ultimately comes down to your priorities and how you use your RV. Here’s how I frame the decision for customers who walk into the store asking which one to buy.
Neither choice is wrong. I’ve seen happy customers with both systems. The “best” water heater is the one that matches your camping style, your budget, and your expectations.
The upfront cost difference between these two systems is significant, but the total cost of ownership over five or ten years is closer than most people expect. The Suburban has a lower purchase price and lower installation cost, but you’ll spend more on propane over the life of the unit due to standby heating. The Girard costs more upfront and more to install, but its on-demand operation eliminates standby fuel waste entirely.
Maintenance costs favor the Suburban slightly. Its components are simpler, parts are cheaper, and virtually any RV technician can service it. The Girard has more sophisticated electronics and a heat exchanger that can develop scale buildup in hard water areas, which may require periodic descaling. However, Girard units have proven to be quite reliable in the field, and major failures are uncommon with proper maintenance.
The anode rod in the Suburban tank is a maintenance item that many owners overlook. The anode rod protects the tank from corrosion and should be inspected annually and replaced when it’s substantially consumed. Neglecting this $15 part can lead to a corroded tank and a premature replacement of the entire water heater—a $400–$600 repair that a $15 anode rod would have prevented. The Girard has no tank and no anode rod, so this particular maintenance item doesn’t apply.
When I factor in propane savings, reduced maintenance complexity, and the elimination of anode rod replacements, the Girard’s higher upfront cost typically breaks even within three to four years of full-time use. For weekend and seasonal campers, the payback period is longer—five to seven years or more—which makes the Suburban the more economical choice for lighter use patterns.
After selling both systems for years, I’ve collected a lot of real-world feedback that goes beyond spec sheet comparisons. The most common positive comment from Girard owners is about the shower experience. “I can finally take a real shower” is something I hear constantly. The unlimited hot water genuinely changes the daily routine for full-timers and families, and it’s the single feature that generates the most enthusiastic customer loyalty.
The most common complaint from Girard owners is about the “cold water sandwich” effect. When you turn off the hot water briefly and then turn it back on—say, while lathering your hair in the shower—the first few seconds of water that comes out may be cold because the burner shut off during the pause and needs a moment to reignite and reheat the water flowing through the exchanger. Experienced Girard owners learn to either leave the water running during their shower or accept the brief cold burst. It’s a minor inconvenience, but it surprises first-time tankless users who aren’t expecting it.
Suburban owners consistently cite reliability and peace of mind as their primary satisfaction drivers. “It just works” is the refrain I hear most often. There’s a comfort in knowing that your water heater uses time-tested technology, can be repaired at any RV shop in the country, and doesn’t require any learning curve or behavior changes. For RV owners who want their rig to operate simply and predictably, the Suburban delivers that experience consistently.
The most common Suburban complaint is predictably about running out of hot water. Families with teenagers, couples who both want morning showers, and anyone who’s tried to wash a sinkful of dishes right after someone showered knows the frustration of a depleted tank. The 20–30 minute recovery time feels like an eternity when you’re standing in the bathroom waiting for the water to heat back up. This is the exact problem that drives most Suburban owners to consider the Girard upgrade.
The Girard tankless and the Suburban tank-style water heater represent two genuinely different philosophies about RV hot water. Girard offers the modern, high-performance approach: unlimited hot water, on-demand heating, and fuel efficiency that comes with a higher price tag and a more complex installation. Suburban offers the proven, reliable approach: predictable performance, easy serviceability, and a price point that makes it accessible to every RV owner.
If you’re upgrading from a failed water heater and want the easiest path back to hot showers, the Suburban is hard to beat. If you’re building your dream rig or upgrading systems across the board and want the best possible hot water experience, the Girard delivers something a tank heater simply can’t match. Either way, you’re buying from brands with strong reputations and products that are specifically engineered for the RV environment.
If you’re on the fence, give us a call at the store. I’m happy to walk through your specific setup—your RV type, your camping style, your hot water demands—and help you figure out which system is the right fit. It’s a decision worth getting right, because you’re going to live with it for a long time.
I’m Bill Rowell, the founder of RVupgrades.com. In 2002, I launched the business to help fellow RV enthusiasts find unique and hard-to-find products. Over the years, it’s grown to offer more than 15,000 items, with a warehouse in Eastlake, Ohio. Having owned and repaired nearly every type of RV, I bring over two decades of hands-on experience to the table. For me, this isn’t just a business – it’s a passion and a way of life that I love sharing with the RV community.
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