Rinnai makes gas tankless water heaters that heat water as it flows, so you don't run out the way a tank can. CASC is a Rinnai PRO and installs Rinnai tankless units across Central Arkansas, sizing the unit to your fixtures, checking gas and venting, and registering your equipment.
What is a Rinnai tankless water heater?
It's a wall-mounted gas water heater that fires a burner only when you open a hot tap, heating water on demand instead of keeping a tank hot all day.
Rinnai is a manufacturer widely known for gas tankless water heaters. Its residential line includes indoor and outdoor models, non-condensing and condensing designs, and models built for different household sizes.
Because a tankless unit makes hot water as you use it, the limit is flow rate, measured in gallons per minute, not tank size. Sizing is about how many fixtures might run at once.
When you open a hot tap, a flow sensor tells the unit water is moving, the burner fires and a heat exchanger warms the water to the set temperature on its way to the fixture. When the tap closes, the burner shuts off. There's no tank sitting at temperature between uses, which is where tankless units save standby energy.
Condensing or non-condensing: what's the difference?
Condensing models capture extra heat from the exhaust and vent through plastic pipe. Non-condensing models vent hotter exhaust through metal venting and cost less upfront.
Which one fits depends on where the unit goes, how venting can be routed and your efficiency goals. Some Rinnai models also offer recirculation features that shorten the wait for hot water at distant taps. We'll explain what applies to your layout.
When does a Rinnai tankless make sense?
Tankless fits homes that run out of hot water, want to free up floor space or plan to stay in the home for years.
Tankless units also mount on a wall, which frees floor space in a garage or utility closet. Rinnai makes models for different household sizes, so one unit can often cover a whole home when it's sized to the fixtures that run together.
If your home is all-electric, or the gas line can't be upsized practically, a Bradford White tank may be the simpler choice.
- Back-to-back showers that drain a tank.
- A garage or closet where a bulky tank is in the way.
- Gas service with room to support the unit's gas demand.
What goes wrong with tankless water heaters?
The usual troubles are mineral scale, undersized gas lines, venting mistakes and units sized too small for the household. Most are installation or upkeep issues.
Minerals in hard water can build up inside the heat exchanger. Periodic descaling keeps flow and efficiency where they should be. A gas line that was fine for a tank may be too small for a tankless burner, which shows up as fluctuating temperatures when several taps run.
Other common issues include venting that's too long or poorly sloped, a condensate line on a condensing unit that isn't drained correctly, and an inlet water filter screen that clogs with debris. Error codes on the unit's display usually point a technician toward the cause.
Homeowners sometimes notice a brief burst of cold water between back-to-back uses, or a minimum flow below which the burner won't fire. Both are normal traits of tankless heating, and good sizing and setup keep them from becoming a nuisance.
How does CASC install Rinnai tankless units?
As a Rinnai PRO, we size the unit to your fixtures, check gas line capacity, plan venting and condensate, and pull required permits.
Before quoting, we look at where the current water heater sits, how the gas line runs from the meter, where venting can exit the house and where condensate can drain. If the install calls for a new gas line or a different location, we explain why and include it in your pricing so there are no surprises.
- Fixture-by-fixture sizing based on how your household uses hot water.
- Gas line installation or upsizing when the existing line can't keep up.
- Manufacturer warranty terms vary by model; we explain what applies to your unit.
How do you get a Rinnai tankless estimate?
Water heater installs qualify for a free estimate. We'll look at your current setup and give you written pricing for tank and tankless options.
Call 501-307-1310, Monday through Sunday, 7 AM to 6 PM. Financing options are available.
Frequently asked questions
Can a Rinnai tankless run out of hot water?
It won't run out the way a tank does, but it can only heat so many gallons per minute. Correct sizing keeps showers steady when several taps run.
Does a tankless water heater need maintenance?
Yes. Periodic descaling removes mineral buildup from the heat exchanger. Many installs include isolation valves that make descaling easier, so ask about them when you plan the install.
Can I put a tankless unit where my tank is now?
Often, but gas line size, venting and condensate routing decide it. We check all three before quoting.
Terms on this page
Related guides
- How tankless water heaters work A tankless water heater heats water only when you open a hot tap. A flow sensor fires a gas burner, and water passes through a heat exchanger on its way to your faucet. Output is limited by flow rate and how much the water must be warmed, so sizing, gas supply and periodic descaling all matter.
- Tank vs tankless water heater A tank water heater keeps a set amount of water hot and ready, while a tankless unit heats water only when you open a tap. Tankless gives you a steady supply and saves space; a tank is simpler to install and handles several fixtures at once. Your household's hot water use and your gas and venting setup decide the fit.
- Get a free replacement estimate CASC gives free estimates on HVAC replacements, larger plumbing projects like water-heater installs, repipes and sewer replacements, and commercial HVAC projects. A technician visits, looks at your current equipment and home, sizes the job and walks you through options. Request yours through our contact form or call 501-307-1310.
- The brands we install and service Central Arkansas Service Company installs Rheem heating and cooling systems, Mitsubishi ductless systems, Bradford White tank water heaters and Rinnai tankless water heaters. CASC is a Rheem Pro Partner and a Rinnai PRO. We also service all major brands, so you don't need to own one of these to call us.
Ready to go tankless?
Get a free estimate from a Rinnai PRO in Central Arkansas.
Request a free estimate