Rheem High Efficiency Non-Condensing Outdoor Tankless Liquid

The Verdict

Let me be direct: a tankless water heater at $756 sounds like a steal, but the real cost lives in the install details. I’ve dug through 195 owner ratings and technical specs on this Rheem non-condensing outdoor unit. Here’s what actually matters before you hand over your credit card.

What you’re actually getting

The box contains the heater unit itself (28.5" H x 17.5" W x 9.8" D), a wall-mounting bracket, vent terminations for the outdoor installation, and the owner’s manual. That’s it. No water lines, no gas flex line, no shutoff valves. Plan on $50-100 in extra brass fittings and pipe at your local hardware store.

This is the liquid propane version, rated for 180,000 BTU with a max flow of 6.5 GPM. For a 2-bathroom home running one shower plus a sink simultaneously, that’s adequate. Three bathrooms or a rain showerhead? You’ll feel the limits.

Performance in the real world

The 0.82 UEF rating is honest — it’s not the most efficient tankless on the market, but it’s a clear step up from a 0.58-0.62 UEF tank water heater. Multiple owners report 20-30% drops in their propane bills after switching.

One owner put it plainly: “Gas bill went from $89/month to $61/month with same usage. Unit paid for itself in about 18 months.”

Hot water delivery is consistent at 1.5-3 GPM flow rates. Set the temperature to 120°F on the digital display, and you’ll get steady output. The self-diagnostic LED panel shows error codes that are actually documented in the manual — a rarity at this price point.

Where it stumbles

Here’s the catch with non-condensing units: they vent hot exhaust directly outdoors, so efficiency plateaus. You’re sacrificing 15%+ thermal efficiency versus a condensing model that recaptures flue heat. If you live in a cold climate (below 40°F inlet water), expect reduced flow rates in winter — the heater can only raise water temperature by about 50°F at full flow.

The 0.5 GPM minimum ignition flow is a genuine annoyance. Low-flow showerheads (1.5 GPM or less) work fine, but a faucet barely cracked open won’t trigger the burner. You’ll get a cold splash before it kicks on. Several owners mention this exact issue: “Turn the bathroom sink to a trickle for shaving and it’s ice cold. You learn to run it full blast.”

Installation requires a 3/4-inch gas line and a dedicated 120V outlet. If your current setup has 1/2-inch line, budget $200-500 for a plumber to upgrade it. That pushes the real cost past $1,000 — at which point a condensing unit starts looking smarter.

Who should buy this

Buy it if: You’re handy enough to handle the gas line yourself, have propane already, need to replace a tank unit outdoors, and your water demands are modest (1-2 simultaneous fixtures). The outdoor mounting saves serious indoor space.

Skip it if: You have hard water (scale buildup will kill it without a softener), need consistent flow in freezing climates, or want maximum efficiency for the long term. Condensing units cost $300-500 more but reclaim that difference in gas savings within 3-5 years.

Frequently asked questions

Q: Does this work in freezing temperatures? The unit has freeze protection down to -30°F, but it only activates when power is connected and the heater is in standby. If you lose power during a freeze, drain the unit or risk cracked heat exchangers. Outdoor installation in northern climates is risky.

Q: What’s the lifespan compared to a tank heater? Rheem rates the heat exchanger for 15 years with proper water chemistry. Hard water cuts that dramatically — a 5-grain hardness level requires a softener or annual descaling. Tank heaters typically last 8-12 years.

Q: Can I install this myself? If you’re comfortable with gas line work and local code compliance, yes. Most municipalities require a permit and inspection. The electrical is simple — just a grounded 120V outlet. But the gas line sizing is critical; undersized lines cause pressure drops that trigger error codes.

The Verdict

Rating: 3.7/5

The Rheem non-condensing outdoor tankless delivers on the basics — endless hot water, compact footprint, and measurable gas savings. It’s a solid mid-tier choice for a specific buyer: moderate water usage, propane available, willing to handle or pay for proper gas line installation.

But the 0.5 GPM ignition threshold, efficiency ceiling, and hidden install costs keep it from being a universal recommendation. If you’re on the fence, price out the total install cost first. At $756 plus $300+ in install materials and labor, you’re approaching condensing-unit territory with better efficiency and cold-weather performance.

Buy it if you need a straightforward outdoor replacement, have modest hot water needs, and want to avoid the indoor venting complexity of tank models. Skip it if you’re in a cold climate, have hard water without treatment, or plan to run multiple high-flow fixtures simultaneously.

Where to Buy

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Last updated: 2026-08-06. Ratings and prices current as of review date. Verify on Amazon before purchasing.