Durham Region’s rapid growth over the last decade means thousands of homes in Oshawa, Whitby, Ajax, Pickering and Clarington are still running aging tank-style water heaters that can’t keep pace with modern households, and David’s been replacing and servicing them across the region since 2011. He covers all Durham Region communities and picks up the phone himself, so you won’t wait days to reach someone who knows what they’re talking about.
From new installations in Oshawa’s growing subdivisions to emergency repairs in Pickering’s older lakefront homes, David handles every tankless water heater job across Durham Region personally.
David sizes every installation to match the actual hot water demand of your home. Many Durham Region properties built in the 1990s and early 2000s have utility rooms that weren’t designed for tankless units, so he’ll assess the gas line capacity and venting route before quoting a dollar figure. You’ll know exactly what the job costs before he starts.
Error codes, ignition failures, fluctuating water temperatures, David diagnoses the root cause rather than swapping parts until something works. He carries common components for the major brands so most Durham Region repair calls wrap up in a single visit.
If your unit’s beyond repair, David won’t pressure you into the most expensive model on the shelf. He’ll tell you what makes sense given your household size, gas line setup, and budget. Replacements across Durham Region typically take three to five hours and he hauls the old unit away.
Ontario’s hard water deposits scale inside heat exchangers faster than most homeowners expect. An annual flush and inspection keeps your unit running at rated efficiency and catches small problems, like a partially blocked inlet filter or a worn igniter, before they leave you without hot water mid-winter.
Upgrading from a standard 80% efficiency tank to a condensing tankless unit at 96% or higher cuts gas consumption noticeably, and current Enbridge rebates make the switch more affordable than it was two years ago. David walks you through the numbers so you can decide whether the payback period makes sense for your situation.
A tankless unit that stops working on a January morning in Clarington or Courtice isn’t something you want to wait two days to fix. David serves all of Durham Region on emergency calls and he picks up the phone himself at (416) 508-4585. You’ll talk to the person doing the work, not a dispatcher booking someone else.
Since 2011, I’ve worked on tankless water heaters in homes across Oshawa, Whitby, Ajax, Pickering and Clarington, and the same issues come up repeatedly: units that were undersized at installation, gas lines that were never upgraded to handle the demand, and scale buildup from Durham Region’s moderately hard water that nobody flushed out for five years. I fix the problem you called about and I tell you honestly if anything else needs attention.
Every quote I give reflects the actual job. I won’t add charges once the work starts. If I think a repair makes more sense than a replacement, I’ll say so and explain why.
A gas tankless water heater installed correctly and maintained properly will typically last 18 to 22 years in Ontario. That’s roughly double the lifespan of a conventional tank unit. The main variables are water quality, frequency of service, and whether the unit was sized correctly at installation. An undersized unit that runs at full capacity every day wears out its heat exchanger and fan motor faster than one with headroom to spare.
Ontario’s water supply, including municipal water across most of Durham Region, carries enough dissolved minerals to scale a heat exchanger meaningfully over three to five years without a flush. Scale acts as insulation inside the heat exchanger, forcing the burner to run longer to hit the target temperature. That extra thermal cycling accelerates wear. An annual descaling flush is the single maintenance step that extends lifespan most reliably.
Cold Ontario winters also put demand on tankless units in a way that milder climates don’t. When the incoming groundwater temperature drops to 4 or 5 degrees Celsius in January, the unit has to work harder to raise it to 49 or 50 degrees. That’s normal, but it means a unit that’s borderline on capacity in summer will struggle visibly in winter. I see this often on calls in Oshawa and Ajax where a builder-grade unit was put in during a mild season and the homeowner only notices the shortfall once the cold arrives.
A straightforward tankless water heater installation in Durham Region, replacing an existing tank unit and using the existing gas line and a new exterior wall vent, runs between $2,800 and $4,200 fully installed. That range covers labour and a mid-range condensing unit from a reliable brand. Higher-end units with recirculation pumps and Wi-Fi monitoring push the installed cost to $4,500 to $5,500 depending on the model.
What drives the variation is almost always the gas line. Many Durham Region homes built before 2000 have a 1/2-inch gas line feeding the utility room, and a tankless unit typically needs 3/4-inch supply to operate at full flow. Upgrading that line adds $300 to $600 to the job. Venting runs also affect cost: a short direct vent through an exterior wall is straightforward, but routing through a finished basement ceiling to reach an exterior wall adds time. I quote every job after seeing the utility room, not from a phone conversation, so the number you get reflects the actual work involved.
Repair costs range from $150 for a sensor or igniter replacement to $600 or more for a heat exchanger. On a unit older than 12 years, I’ll be upfront about whether the repair cost relative to the unit’s remaining life makes sense. The best way to know what your specific job will cost is to get a free quote from David, no pressure, no obligation.
Durham Region’s housing stock spans a wide range. Pickering and Ajax have significant concentrations of homes built in the late 1970s through the 1990s, many of them semi-detached and detached two-storeys with utility rooms tucked into tight basement corners. These homes were designed around 40 or 60-gallon tank heaters, and the gas lines and venting clearances weren’t planned with tankless units in mind. It’s workable in almost all cases, but it takes someone who knows what they’re looking at.
Oshawa’s north end and the Courtice area have seen substantial new construction since 2010, and many of those homes came with tankless units already installed by the builder. Builder-grade installs are sometimes done with minimum-spec gas lines and shorter-than-ideal vent runs to keep costs down. When those units hit year seven or eight, they start showing symptoms, ignition errors, temperature swings, that trace back to the original installation rather than a defective unit. I’ve serviced enough of these in Courtice and north Oshawa to know the pattern.
Clarington and the Bowmanville area include a mix of newer subdivisions and older rural properties. Some rural properties in Clarington are on propane rather than natural gas, which requires a different orifice kit and regulator setting. A few contractors miss this detail or don’t mention it upfront. I confirm the fuel type before I quote any job in that area so there are no surprises on installation day.
The clearest sign something’s wrong is an error code on the display panel. Most modern tankless units from Navien, Rinnai, Noritz, and Bosch have self-diagnostic systems that flag the specific fault, ignition failure, overheating, sensor error, flow rate problem. Writing down that code before you call saves time because it tells me what I’m likely dealing with before I walk through your door. If your unit’s running but displaying a persistent fault code, don’t ignore it; intermittent codes often escalate into full shutdowns within weeks.
Temperature fluctuations, hot water that swings from warm to scalding to lukewarm mid-shower, usually point to a flow sensor or heat exchanger scale issue. This complaint comes up frequently in Durham Region homes that haven’t had an annual service, particularly in areas of Whitby and Ajax where municipal water carries a moderate hardness level. Scale builds gradually and the symptoms creep up slowly, so homeowners often tolerate them for a year before calling.
Reduced hot water volume, where the unit used to handle two showers simultaneously but now can’t, is worth investigating immediately. It’s sometimes a partially blocked inlet filter, which takes minutes to clean, but it can also signal a failing gas valve or heat exchanger degradation. Either way, it won’t improve on its own.
Durham Region’s winters are cold enough that incoming water temperatures routinely drop below 5 degrees Celsius from December through February. At that inlet temperature, a unit rated for 8 gallons per minute at a 35-degree rise will only deliver that flow at a 49-degree output, which is fine for most households but tight for a family running a bath, two showers, and a dishwasher simultaneously. Knowing your unit’s temperature-rise chart helps you use it smartly in winter.
Setting your unit’s target temperature to 49 degrees Celsius rather than pushing it to 55 or 60 reduces fuel consumption without sacrificing comfort for most households. If you have a large soaker tub or a rain-head shower that draws high flow, a recirculation pump combined with a hot water line to the fixture keeps wait times short and avoids the “cold water sandwich” effect, which is that burst of cold water that arrives between warm draws when the unit cycles off and on.
Spring is the ideal time to book an annual flush in Durham Region. After a winter of high demand, scale deposits have had the full season to build up, and addressing them before summer reduces the workload on the unit during peak summer usage when vacation schedules send hot water demand spiking again.
Any gas appliance work in Ontario, including tankless water heater installation and repair, requires a TSSA licence. That’s not a formality. It’s the mechanism by which the province confirms the technician understands combustion safety, proper venting, and CO risk. My TSSA licence number is #000398183 and you can verify it directly on the TSSA website. An unlicensed installation voids manufacturer warranties, creates liability if something goes wrong, and may invalidate your home insurance. When you’re evaluating contractors, ask for the licence number, not just a claim of being licensed.
Tankless units vent combustion gases directly through the wall or roof, and the exhaust side carries carbon monoxide. A cracked, disconnected, or improperly pitched vent pipe is a CO risk. I check vent integrity on every service call, not just on installations. Ontario building code also requires CO detectors on every level of a home that contains a gas appliance, and on every level that has a sleeping area. If yours are more than seven years old, replace them.
On the efficiency side, Ontario homeowners can access Enbridge Gas rebates for high-efficiency condensing tankless water heaters under the Home Efficiency Rebate Plus program. Qualifying units typically need to meet a specific energy factor threshold. The rebate amount changes periodically, but as of 2024 it’s been meaningful enough to affect the payback calculation for homeowners comparing a mid-efficiency unit to a condensing model. I’ll confirm current rebate eligibility during the quoting process.
Checking the simple things before calling saves time for everyone.
Tankless units have self-diagnostic displays. Write down the error code and call Cassar, this tells us exactly what’s wrong before we arrive.
There’s a small mesh filter screen on the cold water inlet that catches debris. It blocks up over time and restricts flow enough to prevent ignition.
Make sure the gas shutoff valve behind the unit is fully open. It can get partially closed during other work in the utility area.
Running multiple hot water fixtures simultaneously can exceed the unit’s flow capacity, causing a cold burst. Try running one fixture at a time to test.
Tankless units vent through the wall or roof. Check that the intake and exhaust pipes are clear, undamaged, and properly connected.
If none of the above resolves it, the unit needs a licensed technician. David serves all of Durham Region and picks up the phone himself.
For most Durham Region households, yes, the numbers work. A condensing tankless unit runs at 94 to 96 percent efficiency versus the 60 to 80 percent you get from an aging conventional tank, and Enbridge’s natural gas rates mean that gap translates into real savings on your monthly bill. The upfront cost is higher, roughly $2,800 to $5,500 installed compared to $900 to $1,400 for a tank replacement, but the unit lasts 18 to 22 years compared to 10 to 12 for a tank, and there’s no standby heat loss from a tank sitting in your basement cycling on and off all day.
Durham Region’s water hardness is moderate but real. That does mean you’ll need an annual flush to keep the heat exchanger efficient, which is a minor ongoing cost. For families in the region running two or three showers regularly, the on-demand delivery also eliminates the “ran out of hot water” problem entirely. Where I tell homeowners the math is tighter is when they’re planning to sell in two or three years, the payback period on the premium is longer than that. But for someone staying in their home, it’s usually a solid investment. The best way to know what your specific job will cost is to get a free quote from David, no pressure, no obligation.
A standard tankless installation in Durham Region, where the gas line is already 3/4-inch and the venting route is straightforward, runs between $2,800 and $4,200 fully installed including the unit. That covers a mid-range condensing model, Navien, Rinnai, or Noritz, which is what I recommend for most homes in this area. Premium units with built-in recirculation and remote monitoring add another $600 to $1,200 to that figure.
The factors that push costs higher are gas line upgrades (typically $300 to $600 if your current line is 1/2-inch, which is common in homes built before 2000 across Ajax, Pickering and Oshawa), complex venting routes through finished walls or ceilings, and permit requirements on certain job types. Repairs range from $150 for a straightforward sensor swap to $500 or $600 for a heat exchanger or gas valve replacement. I won’t quote a job without seeing the utility room first, because the number I give you on the phone without that visit often bears no relation to what the job actually involves. The best way to know what your specific job will cost is to get a free quote from David, no pressure, no obligation.
It depends on which unit you install and how it’s sized, and sizing is where most installations go wrong. A properly sized tankless unit for a Durham Region household of four to five people typically needs to deliver 7 to 9 gallons per minute at a temperature rise of around 45 degrees Celsius to handle two simultaneous showers plus a running dishwasher. That requires a mid-range to large condensing unit, not the entry-level models some contractors default to because they’re cheaper to supply.
In winter, incoming groundwater temperatures in Ontario drop to 4 or 5 degrees Celsius, which means the unit needs a higher temperature rise to hit your set point. That reduces the maximum flow rate the unit can deliver at the target temperature. A unit that handled everything in September may feel slightly short in January. I factor the winter inlet temperature into every sizing calculation because I’ve seen too many installs in Durham Region that work fine in summer and underperform from December through February. I’ll run the numbers with you during the quote so you know exactly what you’re getting.
Most tankless water heaters require a 3/4-inch gas supply line to operate at full capacity. The problem is that a large proportion of homes in Durham Region built before 2000, particularly semis and detached two-storeys in Ajax, Pickering, and south Oshawa, have 1/2-inch gas lines running to the utility room. A 1/2-inch line restricts the gas pressure enough that the unit can’t reach full firing rate, which means temperature drops under high-demand conditions even if the unit is otherwise perfectly installed.
Upgrading the gas line from 1/2-inch to 3/4-inch typically costs $300 to $600 depending on the run length and whether it goes through finished walls. It’s TSSA-regulated work, meaning it has to be done by a licensed contractor. I include a gas line assessment in every installation quote so you know before we start whether an upgrade is needed and what it costs. This isn’t a surprise I add after the fact. If the line’s fine as-is, I’ll tell you that too. The best way to know what your specific job will cost is to get a free quote from David, no pressure, no obligation.
A straightforward tankless water heater installation, replacing a conventional tank and using an existing properly sized gas line and a new direct-vent through an exterior wall, takes three to five hours from start to finish. You’re without hot water for that window, but the house stays fully functional otherwise. I typically schedule these as morning jobs so hot water is back on before the afternoon.
Jobs that take longer are those requiring a gas line upgrade, a longer or more complex venting run, or conversion from a tank to a recirculating system with a dedicated hot water return line. Those can run six to eight hours. I’ll tell you during the quoting visit how long to expect, so you can plan around it. I bring everything needed on the truck for standard installs and don’t make multiple trips back to a supply house, which is one of the main reasons jobs run long with some contractors. I’ll also remove and dispose of your old tank before I leave.
Cold water from a tankless unit is almost always one of four things: the unit isn’t igniting, the flow rate is below the activation threshold, the inlet filter is blocked, or the gas supply is restricted. Start by checking whether there’s an error code on the display, that’s the fastest way to narrow it down. If the display shows an ignition fault, check that the gas valve is fully open and that other gas appliances in the house are working normally. If they aren’t, the issue may be upstream with your gas supply rather than the unit itself.
The “cold water sandwich” effect, which is that burst of cold water that arrives a few seconds into a hot draw, is a different issue. It happens when the unit shut off after a previous draw and the water sitting in the pipes between the unit and the fixture has cooled down. A recirculation pump solves this. In Durham Region homes where the utility room is far from the main bathrooms, particularly in larger detached homes in Whitby’s newer subdivisions, this complaint comes up regularly. It’s not a unit defect, but it is fixable. If your unit is producing cold water entirely rather than a brief cold burst, call me, it needs a proper diagnosis.
Once a year is the right interval for most Durham Region homes on municipal water. The annual service involves flushing the heat exchanger with a descaling solution to remove mineral buildup, cleaning the inlet filter screen, inspecting the burner and igniter, checking the venting integrity, and verifying the unit is firing at rated efficiency. The whole job takes about 60 to 90 minutes on site.
If your home has particularly hard water, or if you’ve noticed the unit running longer to reach temperature than it used to, twice-yearly flushes might make sense. I check water hardness during the first service call and factor it into my recommendation. Skipping annual service is the fastest way to shorten the lifespan of a tankless unit, scale accumulates inside the heat exchanger and acts as insulation, forcing the burner to overwork. Most manufacturer warranties also require documented annual service to stay valid, so skipping it can affect your coverage. I serve all of Durham Region for maintenance calls, including Clarington, Bowmanville, and Newcastle.
Yes. I work on all the major gas tankless brands sold in Ontario, including Navien, Rinnai, Noritz, Bosch, Bradford White, Rheem, and A.O. Smith. Each brand has its own diagnostic codes and service procedures, and I carry parts for the most common models on the truck so I don’t have to make a second trip for standard repairs. For less common units or older models that require sourced parts, I’ll confirm parts availability and lead time before starting any work.
On installations, I typically recommend Navien or Rinnai for most Durham Region households. Both have excellent track records for reliability, strong parts availability across Canada, and dealer support networks that matter if you ever need warranty work. I’m not locked into any single brand, so my recommendation is based on what fits your home’s gas line configuration, your household’s hot water demand, and your budget, not on margin. I’ll walk you through the options during the quoting visit so you can make an informed decision.
“Our Navien unit in our Whitby home threw an ignition error and David had it diagnosed and repaired the same afternoon. Cold water problem gone.”
“We were replacing a 40-gallon tank in our Ajax house and weren’t sure whether to go tankless. David came out, looked at our gas line, checked the utility room, and explained exactly why our current 1/2-inch line would need upgrading and what that would cost. He gave us the full number upfront, unit, labour, gas line, everything. No surprises on the day. He was right about the timeline too, wrapped up by 2 in the afternoon.”
“I’d gotten two quotes before calling Cassar and both were vague on what was actually included. David’s quote listed every line item. When the job was done the price matched exactly. He also put down a mat in the utility room and cleaned up after himself, which I didn’t expect. Solid work throughout our Oshawa home.”
David covers every community across Durham Region, find your city below for local service information.
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