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    Johnson Bros. Plumbing & Drain Cleaning

    Tankless Water Heater Installation & Service — South Shore, MA

    Endless hot water, 30–50% less gas, and no more 50-gallon tank on the floor. Done right, a tankless install lasts 20 years. Done wrong, it fails every winter.

    Johnson Bros. is a family-owned licensed plumber in Quincy & Abington. We size, install, permit, and maintain tankless systems for the South Shore — not just sell them.

    Call (617) 479-9911Book Tankless Consultation
    4.8 stars on Google · 367 reviews across Quincy and AbingtonMA Lic. PL #17034-MFamily-owned · not a franchiseQuincy & Abington offices

    Tank vs. Tankless — Honest Trade-Offs

    Traditional Tank Water Heater

    Where it wins:

    • • Lower upfront cost (~half of tankless)
    • • Simpler install — fewer code upgrades
    • • Works fine for predictable hot water use
    • • Can run multiple fixtures at once on short draws

    Where it loses:

    • • 10–15 year lifespan before the tank fails
    • • Runs out after long showers / back-to-back use
    • • Constant standby heat loss (gas bill)
    • • Floor space for a 50+ gal tank

    Best fit: Tight budget, stable household size, existing setup already tank-based. If a tank is what you need, see our tank water heater page.

    Tankless Water Heater

    Where it wins:

    • • Endless hot water on demand
    • • 20+ year lifespan with annual service
    • • 30–50% less gas use (no standby loss)
    • • Wall-mounted — no floor footprint
    • • Some models qualify for Mass Save rebates

    Where it costs you:

    • • Higher upfront (unit + install)
    • • May need upsized gas line + new venting
    • • Requires annual descaling to last
    • • Hard water shortens heat exchanger life

    Best fit: Growing family, multi-bathroom homes, anyone wanting to get 20 years out of a single install. See our Navien specialty page for our flagship brand.

    Tankless Brands We Install & Service

    We install what fits the house, not what’s in the truck. Our two flagship brands are Navien (tankless water heaters and combi boilers) and Viessmann (German-engineered combi boilers with tankless-style domestic hot water). We also install and service Rinnai when it’s the right call for a retrofit.

    Navien (flagship specialty)

    NPE-A2 (with built-in recirc), NPE-S2 standard tankless, and NCB/NFB combi boilers. Strong cold-climate behavior, clear diagnostics, and South Shore parts availability.

    Navien installer & service details
    Viessmann (flagship specialty)

    German high-end combi boilers — Vitodens 100-W and Vitodens 200-W. Long service life, modulating condensing combustion, and tankless-style domestic hot water delivered directly from the combi.

    Viessmann installer & service details
    Rinnai

    Solid quality and widely supported. Good fit for retrofits where a Rinnai is already in place and a like-for-like swap is the cleanest path. We install, service, and repair current Rinnai tankless models.

    What a Proper Tankless Install Actually Includes

    This is where “cheap tankless installs” go wrong. Skipping any of these is how you end up with a unit that error-codes every winter.

    Gas line sizing

    Tankless units demand 150–199k BTU. Most old houses have 1/2" gas lines that won’t carry it. Undersized gas is the #1 hidden reason tankless systems struggle.

    Venting

    Concentric stainless or PVC venting to a code-approved exterior termination. Not a reused B-vent. Not stretched past its max run.

    Condensate drain

    Condensing tankless units produce acidic condensate. It needs a neutralizer and a code-approved drain — not a bucket.

    Isolation / flush valves

    Without them, the annual descale is a 4-hour job instead of a 45-minute one. We install them on every tankless.

    Permit & inspection

    Every tankless install in Massachusetts requires a permit. We pull it, the town inspects, the job is recorded. Future buyers will thank you.

    Commissioning & combustion check

    We verify combustion, flow, and temperature rise before we pack up. Not “it fired — good enough.”

    Some tankless models qualify for Mass Save rebates

    High-efficiency condensing gas tankless and heat pump water heaters may be eligible. Program details and amounts change — we install qualifying equipment and help with the paperwork.

    See Mass Save Details

    Tankless Water Heater Service Across the South Shore

    Quincy
    Tankless in Quincy
    Abington
    Tankless in Abington
    Braintree
    Tankless in Braintree
    Weymouth
    Tankless in Weymouth
    Milton
    Tankless in Milton
    Hingham
    Tankless in Hingham
    Hanover
    Tankless in Hanover
    Rockland
    Tankless in Rockland

    Common Questions About Tankless Water Heaters

    Is a tankless water heater worth it in Massachusetts?
    For many South Shore homes, yes — but not all. Tankless works best when you have natural gas, a growing family or heavy hot water demand, and a house that can accept proper gas sizing and venting. The winter inlet water temperature in Massachusetts can dip below 40°F, so units must be sized for worst-case conditions, not summer-day marketing numbers. We size for your actual fixtures and your coldest-week inlet temperature.
    How much does a tankless water heater cost installed?
    Installed cost depends on three variables: the unit itself, what code upgrades the existing install needs (gas line, venting, electrical, condensate), and the permit/inspection. We come out for a $99 service fee that applies toward the work, give you an itemized quote, and let you decide. Expect a tankless install to cost more than a tank replacement — the payback shows up in gas bills and lifespan.
    What brand of tankless do you recommend?
    Johnson Bros. has two flagship specialties: Navien (NPE-A2, NPE-S2 tankless water heaters and NCB/NFB combi boilers) and Viessmann (Vitodens 100-W / 200-W combi boilers that deliver tankless-style domestic hot water). Navien is our go-to for straight tankless water heaters; Viessmann is our go-to when you want European-engineered long-life combi boilers that do heating + DHW in one unit. We also install and service Rinnai when a like-for-like retrofit calls for it. No single brand is right for every house.
    How long do tankless water heaters last?
    Properly installed and maintained — 20 years or more. The heat exchanger is the limiting part, and an annual descale extends its life significantly. A tank water heater usually lasts 10–15 years before the tank itself fails. That lifespan difference is the biggest long-term reason people switch.
    Can I replace my tank with a tankless in the same spot?
    Usually yes, but not always a simple swap. Most conversions involve upsizing the gas line, running new concentric or PVC venting to an approved exterior termination, adding a condensate drain to a suitable location, and running 120V electrical. We do the walkthrough first and tell you exactly what your house needs before we quote.
    Do tankless water heaters need annual maintenance?
    Yes. Every year: flush and descale the heat exchanger, clean the inlet water filter, inspect the flame rod and condensate trap, and verify combustion is in spec. Skipping this is the main reason tankless units fail early. We offer this under the Family Plan or as a standalone annual service.
    Local trust + next step

    Why South Shore homeowners choose Johnson Bros.

    Family-owned and local
    Serving Quincy, Abington, and the South Shore.
    Licensed and insured
    MA Master Plumber License PL #17034-M with insured work and professional standards.
    Clear service path
    We'll review your request and confirm the next available appointment.

    Thinking about going tankless?

    Call if you want to talk through whether a tankless actually fits your house, or book a consultation and we will walk the install with you on-site before quoting anything.

    Call About TanklessBook Tankless Consultation

    Need help fast? Call for urgent plumbing issues. Booking online is best when you want the next open appointment without waiting on the phone.

    Areas we serve
    QuincyBraintreeWeymouthHinghamPlymouthMarshfieldScituateAbington

    Related services

    Navien (our specialty)

    Our flagship tankless and combi-boiler brand — dedicated specialty page.

    Tank Water Heater

    If a tank is the right fit, our traditional water heater service page.

    Mass Save Rebates

    Current rebate status for qualifying high-efficiency water heating.

    Thinking about going tankless?

    Call if you want to talk through whether a tankless actually fits your house, or book a consultation and we will walk the install with you on-site before quoting anything.

    Call About TanklessBook Tankless Consultation

    Call for urgent help now. Book online when you want the next available fit for your schedule.