Almost every tankless installation that disappoints its owner was quoted without checking the gas supply. These units fire at several times the input of a tank, and a line that served the old heater perfectly well is frequently too small. We survey that first, because a number given without it is not really a quote.
Napps Plumbing — Longview & East Texas since 1957
Six things. Two of them are the reason tankless quotes vary so widely between companies.
The item that decides whether your unit performs. We check line diameter, run length, total household gas load and meter capacity before quoting anything.
Tankless venting is different from a tank flue and stricter — usually sealed stainless or concentric, correctly terminated with proper clearances.
Capacity is flow rate at a given temperature rise. Winter groundwater is colder, so the honest sizing is done for January rather than July.
A pair of valves that make annual descaling a straightforward job rather than a partial disassembly. Inexpensive at installation, awkward to retrofit.
Condensing tankless units produce acidic condensate that needs draining and, in many installations, neutralising before it reaches the drain line.
Fitted at the same visit, softening the incoming water protects the heat exchanger and makes the annual descaling less of a chore.
Four failure modes, and all four are decided before anyone turns the water on.
A tank water heater might draw around 40,000 BTU. A whole-house tankless unit can draw 180,000 or more when firing hard. The existing half-inch line that served the tank comfortably will not deliver that, and the symptom is not an error code — it is a unit that quietly fails to reach temperature exactly when several fixtures are running, which is the situation you bought it for. We size the line, check the total household gas load, and confirm the meter can supply it.
Gas Line Installation →Tankless venting is not interchangeable with a tank flue. Condensing units in particular produce cool, wet exhaust that will destroy a masonry or B-vent chimney and can allow combustion products back into the house. The correct vent material, diameter, routing and termination clearances are all specified by the manufacturer, and they are inspected. Reusing what was there is the most common serious shortcut in this category of work.
Water Heater Installation →Tankless capacity is quoted as gallons per minute at a given temperature rise. Incoming water is considerably colder in January than in July, so the same unit delivers noticeably less hot water in winter. Sizing on the optimistic figure produces a system that works beautifully for eight months and disappoints for four. We size on the winter rise.
Tankless Water Heaters →Annual descaling requires isolating the unit and circulating a descaling solution through it. With a pair of purpose-made service valves that is a routine visit. Without them it means partially disassembling the connections every year, which costs more each time and makes it likelier the service simply gets skipped — which is how heat exchangers fail in hard water areas.
Tankless Service →All four before a number, not after.
| Item | Why It Matters | If Wrong |
|---|---|---|
| Gas line size & length | Unit needs full input to reach output | Underperforms under load |
| Total household gas load | Other appliances share the supply | Pressure drops when both run |
| Vent type & termination | Tankless exhaust differs from a tank flue | Safety and code failure |
| Winter temperature rise | Capacity falls as inlet water cools | Disappointing in January |
| Service valve provision | Makes annual descaling routine | Maintenance gets skipped |
Or call 903-758-6482 — 24/7
Survey, fixed quote, one day of work, and a handover that includes the maintenance.
Gas line and meter, vent routing, mounting location, condensate route and existing water connections.
Including any gas or venting work required. No provisional figure that changes once the wall is open.
Old unit removed, tankless mounted, gas and vent completed to spec, service valves and condensate handled.
Flow and temperature verified across fixtures, and we show you the service valves and what descaling involves.
Six things to have straight before signing anything, with anyone.
The survey is the job. Everything else follows from it.
Or call 903-758-6482 — available 24/7
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What people ask before committing to a tankless conversion.
The unit is only part of it. The variables that move the price are whether the gas supply needs upgrading and what venting is required — and those are exactly the items some quotes leave out. We survey both before giving you a figure, so the number is fixed rather than provisional. If you are comparing quotes, ask each company whether they measured your gas line.
Frequently. A tank heater might draw around 40,000 BTU; a whole-house tankless unit can draw 180,000 or more. A half-inch line that served the tank fine will not deliver that. We check the line diameter, the run length, your other gas appliances and the meter capacity, because the whole path has to support it — not just the last few feet.
Usually not, and this is not a technicality. Condensing tankless units produce cool, wet, mildly acidic exhaust that will damage a masonry chimney or conventional B-vent, and can allow combustion products back into the house. The correct material, diameter, routing and termination clearances are specified by the manufacturer and checked at inspection. New venting is normally part of the job.
Typically a full day, sometimes two if significant gas line work or awkward vent routing is involved. That compares with two to three hours for a tank replacement. The extra time is almost entirely the gas and venting rather than the unit itself.
It is set by flow rate at a temperature rise, not by household size. We work out how many fixtures might run simultaneously, then size for winter inlet water rather than summer — because incoming water is considerably colder in January, and a unit sized on the optimistic figure will disappoint for a third of the year.
Always, as standard. They are a pair of isolation valves that let the unit be flushed and descaled without disassembling the connections. They cost very little at installation and they are awkward to retrofit — and because descaling is annual in this water, anything that makes it harder makes it likelier to be skipped.
Tankless basics, gas lines and water treatment each have their own page.
We survey the gas line and venting before quoting — which is why our price does not change afterwards.
Tell us your current heater type, whether you have gas service, and how many bathrooms the house has. We will arrange a survey.
