Rheem Tankless Water Heater Install Cost in 2026

Two product families, very different pricing

Rheem's residential tankless catalogue splits cleanly into condensing (RTGH) and non-condensing (RTG). The technology choice drives a $500 to $1,200 spread on installed cost.

RTGH series, the condensing range

The RTGH series covers 8.4 to 9.5 GPM whole-house demand at $1,500 to $2,000 unit cost. UEF runs 0.93 to 0.97. Models in the lineup include the RTGH-90DVLN (8.4 GPM, 0.93 UEF, $1,500), RTGH-95DVLN (9.5 GPM, 0.94 UEF, $1,700) and RTGH-95XLN (9.5 GPM, 0.97 UEF, $2,000). The XLN is the only Rheem that pairs the highest UEF rating with the highest GPM band, which is what makes it the credit-eligible default for 3-bath houses with strong demand profiles.

RTGH installs typically land at $2,800 to $4,200, with the spread driven by gas-line work and venue complexity.

RTG series, the non-condensing budget option

The RTG-84XLN (8.4 GPM, 0.82 UEF, $900 unit) is the model Home Depot positions to price-sensitive buyers. Installed cost is $1,800 to $3,200. The cost saving over an RTGH comes from three places: lower unit cost ($600 to $1,100 less), Category III stainless vent that often fits a re-used existing flue rather than a fresh concentric run, and no condensate-neutraliser line item ($60 to $120). The trade-off is the lower efficiency rating, which costs an extra $30 to $50 a year in fuel at 2026 natural gas prices, and disqualification from the 25C credit.

Itemised installed cost for the RTGH-95DVLN

The middle-of-distribution Rheem install on a 2.5-bath home in 2026:

The high end of this range applies when there is significant scope creep (long gas-line run, complex vent path, attic mounting, hard-water pre-treatment). The low end applies to a like-for-like Rheem-to-Rheem swap where infrastructure is already in spec.

The Home Depot install package, evaluated honestly

Home Depot's tankless install service is delivered through a network of contracted plumbers vetted by Home Depot Home Services. The advertised price for an RTGH-95 turnkey install is around $2,200 to $3,000 in most metros as of mid-2026. This typically includes:

• Removal and disposal of old water heater
• Up to 10 ft of new gas line
• Standard concentric vent kit (up to 15 ft)
• Permit pull and inspection coordination
• Manufacturer warranty registration
• 1-year labour warranty on the Home Depot install

What it does not include, and where the day-of upcharges land:

• Gas-line runs over 10 ft or any meter upgrade ($200 to $1,500)
• Vent runs over 15 ft or non-standard termination ($200 to $600)
• Electrical panel work for whole-home electric models ($500 to $2,000)
• Drywall repair after gas-line resize ($150 to $400)
• Hard-water pre-treatment (a softener installation, $800 to $1,500)

A clean like-for-like swap is well-suited to the Home Depot package and competitive on price. A tank-to-tankless conversion with scope unknowns is usually better served by an independent plumber who can scope and price the whole job before scheduling, rather than discover scope on the day.

Costco's competing install offer

Costco partners with Rheem on a similar install package, available to Costco members in most US metros. The offer typically includes a 2-year labour warranty (vs Home Depot's 1-year), bundled water-softener installation in hard-water markets, and a slightly lower turnkey price ($2,000 to $2,800 for an RTGH-95 install). Members typically save $100 to $300 vs the Home Depot equivalent. The trade-off is geographic coverage: Costco's install network is thinner in non-metro areas.

How the 25C credit affects Rheem ownership cost

RTGH models qualify for the IRS Section 25C Energy Efficient Home Improvement Credit at 30% of installed cost, capped at $600 in any one tax year. A $3,500 RTGH install nets out at $2,900 after the credit, claimed on IRS Form 5695 the following tax year.

The RTG non-condensing models do not qualify (UEF 0.82 is below the 0.95 ENERGY STAR Most Efficient threshold the IRS references). This $600 credit gap is the single biggest reason to spec the RTGH series even though the RTG appears cheaper on the sticker.

State and utility rebates

Rheem condensing units stack with the same utility rebates as Rinnai and Navien:

• Mass Save: $200 to $750 in MA
• NYSERDA Comfort Home: $700 in NY
• Energy Trust of Oregon: $200 to $500
• Xcel Energy MN: up to $400 in MN
• SoCalGas: $300 to $600 on units meeting SCAQMD ultra-low-NOx rule 1146.2 (only the RTGH-RA series qualifies in those CA air districts)

Field reliability and 10-year service profile

Rheem condensing units are reliable in the first 8 to 10 years. The most common service events:

• Heat-exchanger scaling (annual). Descale at home with a vinegar flush, $5 in materials, 45 minutes. Or pay a plumber $80 to $150.
• Flame sensor (years 7 to 10). $90 part, $80 labour.
• Igniter (years 8 to 12). $110 part, $90 labour.
• Gas valve (years 11 to 14). $380 part, $180 labour.
• Control board (years 10 to 15). $320 to $450 part, $130 labour.

Rheem's parts pricing tends to run slightly lower than Rinnai equivalent parts, but the offset is part availability: Rheem distributes through Home Depot and a thin wholesale channel rather than a dedicated dealer network. Allow 2 to 5 days for parts on a non-trivial repair.

Bottom line

Rheem is the right choice when budget is the primary constraint, the install is a like-for-like swap (so the Home Depot package can be competitively priced), and you live in a metro with reasonable Rheem service density. The 10-year total cost of ownership runs $500 to $900 below Rinnai and roughly flat with Navien. The trade-off is service speed once the unit is out of warranty.

For a tank-to-tankless conversion with unknowns, or in markets where the local Rheem service network is thin, the slightly higher Rinnai or Navien install cost is usually worth paying for. For a clean swap in a major metro, Rheem is the value pick.