Rinnai i060CN Condensing Gas Boiler, Whole Home Heating and Water Natural Gas Heater with Space-Saving Design and Smart Features,

Why I switched and what I learned

I replaced an aging cast‑iron boiler and separate tank water heater with the i060CN in a two‑story, mid‑size home with fin‑tube baseboards. I wanted a wall‑mounted, high‑efficiency unit that could handle both space heating and domestic hot water without a separate storage tank. After a full heating season and plenty of showers, here’s how this Rinnai boiler has stacked up.

Design and build

The i060CN is a compact, wall‑mounted condensing boiler with a stainless‑steel primary heat exchanger and a modulating burner. The combination (“combi”) design uses a built‑in plate heat exchanger to produce domestic hot water on demand, so there’s no tank to keep hot. The chassis is tidy and service‑friendly, with a charcoal finish that looks more like an appliance than a piece of industrial equipment.

“Compact” deserves a qualifier: the appliance itself doesn’t eat much wall space, but the system you build around it can. Expect to allocate room for a primary/secondary loop or low‑loss header, air separator, expansion tank, zone valves or pumps, a condensate neutralizer and drain, and two‑pipe venting. In a tight mechanical closet I had to rework existing piping to maintain clearances and keep service access sane. If you’re replacing a floor‑standing boiler and tank, plan a layout on paper first; the wall space you free up is real, but it takes forethought to realize it.

Installation and setup

This is not a DIY project. The i060CN arrives ready to integrate with thermostats and external pumps, and it includes an outdoor reset sensor, but proper installation involves gas line sizing, venting, combustion tuning, and hydronic design decisions that affect comfort and longevity. I hired a licensed pro to:

• Size the unit against the home’s heat loss (do a proper calculation; avoid rule‑of‑thumb oversizing).
• Configure primary/secondary piping for stable flow through the boiler.
• Set up multi‑zone control using thermostat inputs and pump/valve relays.
• Install the two‑pipe direct‑vent and route the condensate drain to a neutralizer.

Commissioning matters. With the outdoor sensor connected and the combustion adjusted, the boiler settled into quiet, stable modulation. Out of the box, it will run; properly tuned, it will run efficiently and comfortably.

Space heating performance

With baseboards, the i060CN’s modulation and outdoor reset are the heroes. I set a fairly low curve, and the boiler adjusts supply temperature as outdoor conditions change. On shoulder‑season days it sips gas, holding radiators just warm enough, and on single‑digit mornings it ramps up to meet demand. The adjustable central heating range (104–180°F) is wide enough to work with baseboard and many panel radiators.

Circulation is external, but the boiler provides control outputs, so you can wire pumps or zone valves directly. In my two‑zone setup, calls were prompt, short‑cycling was rare, and the boiler’s fan and burner noise were easily masked by normal household sounds. Comfort has been excellent—steady room temperatures without the hot‑cold swings older on/off boilers tend to produce.

Domestic hot water performance

The onboard plate heat exchanger produces domestic hot water on demand, with an adjustable setpoint (98–140°F). In practice, showers were consistent and quick to reach temperature, and a kitchen cleanup right after didn’t leave anyone shivering. Like most combis, domestic hot water takes priority; during a long hot‑water draw you may notice space heating pause briefly before recovering. That’s standard behavior and hasn’t affected comfort.

Flow capacity depends on your incoming water temperature and fixture demands. In a typical mid‑Atlantic winter with cold inlet water, the unit kept up with one shower plus a secondary sink without drama. If your household routinely runs two showers and a washing machine at once, you’ll want to discuss sizing and usage patterns with your installer—or consider whether a dedicated indirect tank on a non‑combi boiler better matches your lifestyle.

Controls and “smart” features

The onboard control is practical rather than flashy. The digital display shows temperature and pressure at a glance, and the outdoor reset sensor is easy to enable and adjust. Parameter changes (curves, setpoints, pump timings) are straightforward once you learn the menu logic. There’s also a child‑lock function that prevents tampering with controls and can shut down space heating until unlocked, which is useful in homes with curious hands.

For multi‑zone systems, the boiler accepts thermostat calls and offers integrated control for pumps or valves. It’s not a full‑blown building automation platform, but it bridges cleanly to common third‑party zone controls if you need more sophistication. I ran mine with simple thermostats and let the outdoor reset do the heavy lifting; that combination delivered stable temps and minimal cycling.

Efficiency and operating costs

As a condensing unit, the i060CN is at its best with low return water temperatures. The stainless‑steel heat exchanger shrugged off continuous condensing without complaint, and the modulation kept combustion in a sweet spot for much of the season. Gas usage dropped compared with my previous cast‑iron boiler plus tank, with the biggest gains showing up in the shoulder seasons and in domestic hot water—no standby losses from a tank.

To realize those savings, design for condensing: set the outdoor reset curve so your return temperatures stay below the dew point as often as possible, keep flow rates appropriate, and avoid oversizing. The control range gives you the tools; your installer’s setup and your emitters’ capacity determine how often you can take advantage of it.

Noise, maintenance, and reliability

Day‑to‑day, the boiler is quiet—just a soft fan noise and the occasional relay click. Maintenance is typical for modern condensing equipment: annual inspection, cleaning the combustion chamber as needed, checking condensate drainage and the neutralizer, and flushing the domestic plate heat exchanger if you have hard water. The stainless‑steel heat exchanger is a plus for durability and tolerance to condensing conditions, but water treatment still matters in systems with old radiators or mixed metals.

The warranty is reassuring: up to 12 years on the heat exchanger, 5 years on parts, and 1 year on labor for residential use. That doesn’t replace good installation and water quality, but it’s a respectable vote of confidence in the core components.

What I’d change

• Documentation depth: The manual covers the essentials, but clearer, scenario‑based wiring examples for multi‑zone setups would shorten installation time.
• Accessory planning: A more prescriptive checklist around required clearances and common accessories (header, separator, neutralizer) would help homeowners visualize space needs before committing.
• App connectivity: The onboard controls are capable, yet there’s no out‑of‑the‑box app control. Not a dealbreaker, but remote monitoring and simple scheduling would be welcome in 2025.

Who it’s for

• Homeowners with hydronic heat (baseboards, panels, or radiant) who want a single appliance for space heating and domestic hot water.
• Small to medium homes where a modest domestic hot water load fits a combi’s on‑demand profile.
• Anyone prioritizing efficiency and space savings, and willing to invest in professional design, installation, and regular maintenance.

Who should look elsewhere? Large households with high simultaneous hot‑water demand, or homes with emitters that require consistently high supply temperatures, may be better served by a non‑combi boiler paired with an indirect tank, or by a larger‑capacity system.

The bottom line

The i060CN brings modern condensing performance, a stainless‑steel heat exchanger, and practical controls into a compact, wall‑mounted package that genuinely replaces both a boiler and a tank water heater. Installed and tuned correctly, it runs quietly, sips gas, and delivers steady heat with consistent domestic hot water. It’s not a plug‑and‑play appliance—you’ll want a qualified pro for sizing, venting, piping, and commissioning—and the system around it needs proper space and accessories. But once in, it simply works, and it works efficiently.

Recommendation: I recommend this Rinnai boiler for small to medium hydronic homes seeking an efficient, space‑saving combi solution and willing to use a professional installer. You’ll gain comfort, free up floor space, and likely cut fuel use—without sacrificing hot showers. If your domestic hot water needs are unusually high or simultaneous, consider a different configuration; for most households in this size class, the i060CN hits a very solid balance of performance, footprint, and cost of ownership.