Based on industry pricing data, a tankless water heater typically runs $2,500 to $4,500 installed when it replaces an existing tankless unit, $3,500 to $7,000 for a gas tank-to-tankless conversion, and $4,500 to $8,500 or more when that conversion also needs a larger gas line or new venting. Those are typical installed cost ranges for the market, not a quote from us. The actual price for your home depends on an in-home assessment of your hot water demand, the size of the gas line feeding the unit, where the exhaust can exit, and the condition of the water coming in.
717 Mechanical LLC has installed tank and tankless water heaters across Lancaster County from our shop in Marietta since 2012. We install Navien and NTI tankless units and Bradford White tanks, which puts us in the useful position of not caring which one you buy. This guide explains where the ranges above come from, what pushes a tankless job toward the top of its range, how the lifetime cost of a tankless unit compares with a tank, and what Lancaster County's hard water means for both.
Ready to skip the reading? See our tankless water heater installation page or call (717) 468-9567.
Upfront, Honest Pricing
Sized to Your Home
14+ Years Experience
The table below shows typical installed cost ranges by scenario, based on industry pricing data. "Installed" means the unit, labor, removal and disposal of the old water heater, the standard gas, water, and vent connections, and the permit. The three rows are really three different jobs, which is why the spread from the cheapest to the most expensive is so wide.
| Scenario | Typical installed range (national) | What is usually involved |
|---|---|---|
| Tankless-to-tankless swap | $2,500 to $4,500 | Gas line, venting, and water connections already sized for tankless; unit swap and commissioning |
| Tank-to-tankless conversion (gas) | $3,500 to $7,000 | Remove the tank, mount the unit, new vent run, water and gas reconnection, condensate drain |
| Conversion needing gas line / venting upgrades | $4,500 to $8,500+ | Everything above plus a larger gas line from the meter and a new exhaust and intake route |
Ranges are national averages for context: your home's gas supply, venting route, and water quality change the number. 717 Mechanical quotes your exact price upfront before any work, and that quote comes from an in-home assessment, not a table.
Nearly every whole-house tankless unit we install in Lancaster County is gas-fired, and the ranges above are gas ranges. A gas tankless unit produces enough hot water to run a shower and a washing machine at once, which is what most families expect when they hear "endless hot water." An electric whole-house tankless unit can deliver similar flow only by drawing a very large amount of current at once, and in most of the homes we see, especially the older ones with 100-amp service, that means a panel upgrade and new heavy-gauge circuits before the water heater itself is even considered. The unit is cheaper; the electrical work usually is not. Electric tankless makes the most sense as a point-of-use heater for a single remote bathroom or a garage sink, or in a home with no gas service and an electrical panel with plenty of room. For a whole house on gas, gas tankless wins on both operating cost and installed cost once the electrical work is counted.
On a like-for-like tankless swap, most of the price is the unit itself, because the hard work of sizing the gas line and routing the vent was done when the first unit went in. On a conversion from a tank, the balance shifts toward labor and materials. The tank comes out, the new unit goes on the wall, the water lines are re-routed to a different height, a new PVC exhaust and intake are run to the outside, a condensate drain is added, and the gas line is checked against the new unit's demand. When the gas line and vent are adequate, that is a solid day's work. When they are not, the job becomes the third row of the table, and that is the row most online estimates leave out.
A tankless water heater costs more to install than a tank, and no honest guide will tell you otherwise. The question is whether it costs less to own. The answer depends on how long you plan to stay in the house, how much hot water your household uses, and how you feel about running out of it on a Saturday morning.
| Factor | Tank (Bradford White) | Tankless (Navien / NTI) |
|---|---|---|
| Upfront installed cost | Lower | Higher |
| Lifespan | 8 to 12 years | 15 to 20 years |
| Energy use | Keeps 40 to 50 gal hot 24 hours a day | Heats only on demand |
| Hot water supply | Limited to tank size | Continuous |
| Maintenance in hard-water areas | Annual flush | Annual descaling |
Ranges are national averages for context: your home's gas supply, venting route, and water quality change the number. 717 Mechanical quotes your exact price upfront before any work, and that quote comes from an in-home assessment, not a table.
A tank keeps 40 to 50 gallons of water hot around the clock whether anyone is home or not, and the energy spent reheating that water as it cools is called standby loss. A tankless unit sits idle until a tap opens, then fires only for as long as the water is running. Over a heating season's worth of showers, laundry, and dishes, that difference shows up on the gas bill every month. The second half of the payback is lifespan. A tank that lasts 8 to 12 years in Lancaster County water is replaced once, sometimes twice, over the 15 to 20 years a properly maintained tankless unit runs, and the second tank installation is a cost the tankless owner never pays.
If you plan to sell within a few years, a tankless conversion rarely pays back before you move, and a new Bradford White tank is the practical choice. The same is true for a household of one or two people with modest hot water use, where standby loss is a small number to begin with, and for a home where the gas line and venting would need major work to feed a tankless unit. A tank is also simpler to service: there is no heat exchanger to descale and no error code to read. We install both, and on a quote visit we will tell you which one the numbers favor for your house.
Take the difference in installed cost between the tank and the tankless quote. Then estimate how many years you will be in the house, how many tank replacements that span would include at 8 to 12 years each, and what your current water heating share of the gas bill is. A family of four or five that regularly runs the tank dry, with an existing gas line that can carry the load, tends to close the gap comfortably. A couple in a two-bedroom ranch with a working tank and a tight budget usually does not, and there is nothing wrong with that answer.
Two similar houses on the same street in Mount Joy can get very different tankless quotes. The reasons are almost always on this list, and most of them are things a homeowner can check before the estimate.
This is the single biggest variable in a conversion. A tankless unit heats water instantly instead of slowly, so it fires at several times the BTU rate of the tank it replaces. The half-inch gas line that fed a 40-gallon tank for twenty years often cannot deliver that much gas, especially if it also feeds a furnace, a range, and a dryer along the way. Upsizing means running a larger line from the meter, sometimes across the length of a basement, and in some homes it means asking the gas utility to upgrade the meter as well. When the existing line happens to be three-quarter inch and short, this cost disappears. When it is not, it is the main reason a job moves from the second row of the table to the third.
A conventional tank vents up the chimney through metal B-vent. A condensing tankless unit produces cool, wet, slightly acidic exhaust that cannot use that chimney, so it vents through PVC pipe to an outside wall, with a second pipe bringing in combustion air. The cost depends on how far the unit is from an exterior wall, what the crew has to drill through (block, stone, and brick foundations are all common here), and whether the vent terminal can meet the clearance rules from windows, doors, and the gas meter. Once the water heater stops using the chimney, a furnace that shared the flue may also need a liner, which is worth knowing before the quote rather than after.
A gas tankless unit still needs electricity for its controls, ignition, and fan, so a standard outlet has to be within reach of the mounting location. Most utility rooms have one; some older basements do not. This is a small line item on a gas job. On an electric tankless job it is the whole story, as described above.
Tankless units are sized by how many gallons per minute they can heat and by how much they have to raise the temperature. Groundwater in Lancaster County arrives cold in January, so a unit sized for a southern climate will fall short here in winter. A bigger unit costs more, and a home that wants to run two showers and the dishwasher at once needs a bigger unit than one that runs fixtures one at a time. We size to your actual demand, not to the largest unit on the truck.
Mounting the new unit where the old tank stood is the cheapest option. Moving it closer to an outside wall to shorten the vent, or closer to the kitchen and bathrooms to shorten the wait for hot water, adds plumbing and gas work but can improve the result. A recirculation loop, which keeps hot water at the far fixtures instead of making you wait for it, is a worthwhile add-on in larger homes and a separate line on the quote.
Hauling out the old tank and disposing of it is normally part of the installed price, as is the plumbing permit your municipality requires. Items that can show up as separate lines include isolation valves for future descaling (we consider these essential, not optional), a condensate neutralizer, a drain pan, a water softener or scale filter, and the recirculation loop mentioned above. A written quote should list each of these so you can see exactly what you are paying for.
Lancaster County sits on limestone, and the water that comes out of the ground here carries a lot of dissolved calcium and magnesium. That is what "hard water" means, and it is the single biggest maintenance issue for any water heater in this area. In a tank, the minerals settle as sediment on the bottom and insulate the burner from the water, which is why tanks here rumble, lose capacity, and fail toward the short end of their lifespan. In a tankless unit, the minerals bake onto the inside of the heat exchanger as scale, which narrows the water passages, forces the unit to work harder, and eventually triggers error codes or a cracked exchanger.
Not always, but in most of Lancaster County the answer is closer to yes than no. Manufacturers publish a hardness limit for their units, and much of the water in the county exceeds it. If your home already has a softener, a tankless unit is a natural fit and will run for years with an annual descaling. If it does not, you have three options: install a softener, install a smaller inline scale filter on the cold supply to the water heater, or skip both and commit to descaling the unit more often. The softener is the most complete answer and protects every fixture in the house, but it is a separate project with its own cost. The scale filter is a modest add-on that helps a great deal. Doing nothing is the choice that shortens the life of the heat exchanger and can complicate a warranty claim if scale damage is found. We will test your water hardness on the quote visit and tell you which option fits.
The 15 to 20 year lifespan that justifies a tankless unit's price assumes it is descaled once a year. The procedure is straightforward: with isolation valves installed at the unit, a technician closes off the house water, connects a small pump, and circulates a descaling solution through the heat exchanger for a set time to dissolve the mineral buildup, then flushes it clean. It takes about an hour and it is the tankless equivalent of flushing a tank. Units without isolation valves have to be partly disconnected to do the same job, which is why we install the valves on every job. If you are already in a tankless home and the unit has never been descaled, our tankless water heater repair team can do it as a service visit and check the exchanger and error history while they are there.
We install Navien and NTI tankless water heaters. Both are condensing units, which means they pull extra heat out of the exhaust before it leaves the house and vent through PVC instead of a chimney, and both come in a range of sizes so the unit can be matched to a small ranch or a large family home. Navien is the unit most of our customers ask for by name, with a lineup that covers standard and built-in recirculation models. NTI units are compact, quiet, and a strong fit where wall space is tight. Because we install both, we can recommend the one that suits your gas supply, vent route, and demand instead of steering you toward whatever a single-brand shop happens to stock. Every installation includes sizing to your actual hot water demand, a check of the gas line and venting, isolation valves for future service, and a walkthrough of the controls before we leave. See our tankless water heater installation page for how the process works from the first visit to the final test.
Most tankless conversions start with a tank that is failing, and the timing of that failure has a lot to do with what the job costs. A tank that is replaced on a planned Tuesday in October gets a proper gas line check, a vent route chosen with care, and time to compare a tank quote against a tankless quote. A tank that lets go on a Sunday night gets whatever can be installed fastest, which is almost always another tank. The signs that a tank is near the end are easy to spot: rusty or discolored hot water, a rumbling or popping sound as the burner fires through a layer of sediment, water pooling in the drain pan or on the floor, hot water that runs out sooner than it used to, and an age past 8 to 12 years, which is the typical lifespan for a tank in Lancaster County water. Any one of these on a tank past its eighth year is a reason to get a quote now rather than after the failure. If the tank is younger and the problem is a single part, a repair is usually the better call, and our tank water heater repair team will say so. Typical ranges for those repairs are in our water heater repair cost guide.
A straightforward tank-to-tankless conversion is a one-day job. The crew shuts off the gas and water to the old tank, drains it, and carries it out. The new unit is mounted on the wall, usually where the tank stood or closer to an exterior wall if the vent route is better there. The water lines are re-routed to the unit's connections with isolation valves in place, the gas line is connected and, if it was upsized, pressure tested, and the PVC exhaust and intake are run through the wall to the outside with the terminal placed to meet clearance rules. A condensate drain is run to a floor drain or a small pump. Once everything is connected, the unit is powered up, the gas pressure is checked under load, the temperature is set, and every hot tap in the house is run to purge air and confirm flow. Expect the water to be off for several hours and the crew to walk you through the controls and the descaling schedule before leaving. A job that includes a new gas line from the meter or a long vent run can stretch into a second day, and that is priced and explained in the quote before the first day starts.
A water heater rarely fails at a convenient time, and a tank-to-tankless conversion is a bigger purchase than a like-for-like tank swap. 717 Mechanical LLC offers financing through Service Finance and Wells Fargo, including 0% financing for 60 months on qualifying systems with approved credit. The application is quick and can be done from your phone. Financing often turns the difference between a tank and a tankless quote into a small monthly amount, which is where the lifetime savings from lower standby loss and a longer lifespan start to make sense on paper. Details, terms, and the application links are on our HVAC financing page.
Tankless tends to be the right call when:
Your household regularly runs out of hot water, or you expect it to grow.
You plan to stay in the house long enough for the lifespan and energy savings to pay back.
The existing gas line is adequate or can be upsized without a major project.
You want the floor space back, or the tank sits somewhere a leak would do real damage.
You already have a softener, or are willing to add scale protection and annual descaling.
A tank tends to be the right call when:
You are selling within a few years and want the lowest installed cost.
Hot water use is modest and the current tank size has never been a problem.
The gas line and venting would need extensive work to support a tankless unit.
You prefer the simplest equipment to maintain.
Either way, the water heater should be sized and installed by someone who has done it in Lancaster County water, on Lancaster County gas lines, in Lancaster County basements.
The ranges in this guide are useful for setting expectations, but they cannot see your basement. A quote from a local installer accounts for the things that move the price: the size and length of your gas line, where a vent can exit the wall, how hard your water is, whether the furnace shares the chimney, and how much hot water your family actually uses on a busy morning. The right number for your home comes from an in-home assessment, and we provide that assessment and a written quote upfront, with no pressure to decide that day.
Call (717) 468-9567 for a QuoteAs a family-focused HVAC company, our mission is to provide honest service with a personal touch. We treat every home as if it were our own, ensuring high-quality workmanship and lasting results.
Our shop is on Maytown Road in Marietta, minutes from the river towns of Columbia, Mount Joy, and Wrightsville, and we install tank and tankless water heaters throughout Lancaster County and the neighboring communities in York, Dauphin, and Lebanon Counties. The older homes in these towns often have gas lines and chimneys that were sized for a very different appliance, which is exactly why an in-home assessment matters more than a national average.
Same-day service is available when scheduling allows, and every quote is written and explained before any work starts.
Tell us what you have now, how many people are in the house, and whether you ever run out of hot water, and we will schedule an in-home assessment and put a written price in your hands.
Call (717) 468-9567 to talk through your options.
Prefer to start online? Contact us and we will follow up.
Request a Tankless Quote
© Red Barn Media Group 2026
