Quick answer: In 2026, a tankless water heater costs $3,895 to $7,495 installed in Montgomery County, MD. Net of $1,150-$1,400 in stackable rebates, that's $2,745 to $6,345 out of pocket. Nationally, tankless installs range from $2,400 (suspiciously cheap, often missing permits) to $9,500 (non-specialist plumbers padding quotes). This guide shows you what's included at each price point so you can spot inflated quotes.
The quick answer
For a natural gas condensing tankless install with proper permit and warranty, in Montgomery County, expect:
| Tier | Best for | Fixed price | Net after rebates |
|---|---|---|---|
| Essential | 2-3 bath, 2-4 occupants | $3,895 | ~$2,745 |
| Signature | 3-4 bath, teens, recirc | $5,295 | ~$4,145 |
| Whole-Home Pro | 4+ bath, estates | $7,495 | ~$6,345 |
What you're actually paying for
A proper tankless install has ten distinct cost components. When you see a quote $1,000 below ours, one or more is missing.
- The unit ($1,400-$2,600): A quality Navien, Rinnai, or Rheem condensing tankless
- Permit and inspection ($200-$350): Montgomery County fees plus our time to pull and coordinate
- Labor ($900-$1,400): 6-8 hours for a two-tech team at realistic DMV trade rates
- Venting ($150-$300): Concentric PVC vent + fittings for 15-20 ft run
- Gas connection ($85-$150): Isolation valve, drip leg, flex, sediment trap
- Water connections + service valves ($180-$280): Isolation + descaling valves
- Condensate line ($60-$120): High-efficiency units generate condensate
- Old tank haul-away ($75-$200): Including dump fee
- Initial flush kit ($95-$140): Hardware for annual descaling
- Rebate paperwork ($150-$250 value): 2-3 hours administrative time
Total genuine cost: $3,395-$5,790. That's the real floor. Anything dramatically below is cutting corners — see the hidden-cost mistakes section for what gets cut.
Gas vs electric cost comparison
Gas tankless dominates Maryland installs — not because we prefer gas but because it's the technically correct choice for most family-sized households. Cost comparison for a 3-bath home:
| Configuration | Unit | Install labor | Total |
|---|---|---|---|
| Gas condensing (whole home) | $1,400-$2,600 | $1,900-$2,800 | $3,895-$5,295 |
| Electric whole-home (200A panel) | $800-$1,400 | $1,200-$2,200 | $2,400-$3,800 |
| Electric whole-home (needs panel upgrade) | $800-$1,400 | $3,500-$5,500 | $5,000-$7,500 |
| Point-of-use electric (under sink) | $150-$400 | $300-$600 | $500-$1,100 |
Full detail: gas vs. electric tankless comparison.
Cost by home size
How your home's bathroom count and occupancy maps to tier and price:
| Home profile | Typical tier | Fixed price |
|---|---|---|
| 1-2 bath condo, 1-2 occupants | Essential | $3,895 |
| 2-3 bath townhome, 2-4 occupants | Essential | $3,895 |
| 3 bath colonial, 3-4 occupants | Signature | $5,295 |
| 3-4 bath with teens | Signature + recirc | $5,295 |
| 4 bath, 4-5 occupants | Signature or Pro | $5,295-$7,495 |
| 5+ bath estate, pool/guest house | Whole-Home Pro | $7,495 |
Rebates and tax credits
Four stackable incentives in Maryland. Miss even one and you're leaving real money on the table.
- Washington Gas rebate: Up to $450 for Energy Star tankless — full guide
- Federal tax credit (IRS 25C): Up to $600 — 30% of project cost, capped
- Maryland manufacturer rebate: $100 on select Rinnai/Navien models
- Montgomery County property tax credit: Up to $250 for energy efficiency upgrades
Total stackable: up to $1,400. Full breakdown on our rebates page.
Financing — the monthly math
Most Montgomery County homeowners finance through one of two paths:
| Tier | 0% APR 12mo (Wisetack) | 60mo fixed (GreenSky) |
|---|---|---|
| Essential ($3,895) | ~$324/mo | ~$75/mo |
| Signature ($5,295) | ~$441/mo | ~$102/mo |
| Whole-Home Pro ($7,495) | Exceeds cap | ~$144/mo |
Note: these are rough estimates before rebates apply. Actual payment lower after rebate checks arrive.
20-year total cost of ownership
The real comparison isn't upfront price — it's total cost over the unit's life. Tanks last 10-15 years; tankless lasts 20+. Over a typical 20-year ownership:
| Year | Tank (50gal gas) | Tankless (Signature) |
|---|---|---|
| Install | $2,200 | $4,145 (net of rebates) |
| Year 5 cumulative | $3,600 | $4,620 |
| Year 10 cumulative | $5,000 | $5,095 |
| Year 12 (tank replacement) | $7,300 (+$2,500 new tank) | $5,285 |
| Year 20 cumulative | $9,500 | $6,025 |
20-year savings favoring tankless: $3,475 over a typical homeownership tenure.
Hidden-cost mistakes to watch for
When comparing quotes from multiple Montgomery County plumbers, these are the corners most commonly cut:
Mistake 1 — No permit pulled
Saves $200-$350 on paper. Costs you homeowners insurance coverage for related water damage, creates resale issues, and fails final inspection if buyers request one. Not worth it.
Mistake 2 — Off-brand unit
Amazon-tier tankless units sell for $400-$800 vs. $1,400+ for Navien/Rinnai/Rheem. The problem: parts availability in 5-10 years is near zero, warranty service requires returning units to China, and heat exchanger lifespan drops to 7-10 years instead of 20+.
Mistake 3 — No service valves
Saves $180-280 on install. Makes annual descaling impossible without professional intervention. Dramatically reduces unit lifespan in hard water areas like Rockville and Potomac.
Mistake 4 — Non-condensing unit when condensing was quoted
Saves $400-600 on unit. Loses 10-15% efficiency over the unit's life. Non-condensing units need stainless venting (more expensive if you ever need to replace it).
Mistake 5 — No rebate paperwork filed
Saves contractor 2-3 hours of admin. Costs you up to $1,400 in rebates you'll never claim independently. We include this in every install.
Mistake 6 — Outsourced labor
Some "local" plumbers subcontract to day laborers. Look for licensed master plumber or licensed journeyman credentials on the install team itself, not just the company ownership.
Compare quotes against our published price.
Our tiers are all-in. If your other quote is significantly lower, something above is probably missing.
Next steps
- Run the instant estimator for your specific tier and net price
- Read the Maryland-specific cost breakdown
- Compare to tank heater costs
- Review our full fixed-price tiers and published stipulations
- Book a free 45-minute consult for a firm locked-in quote