Combi Boiler vs Tankless Water Heater | Vancouver

A common point of confusion: a combi boiler also does on-demand hot water — so why have both a tankless water heater AND a separate boiler? Below is the technical and practical breakdown for Metro Vancouver homeowners deciding between (a) a combi boiler that handles heating + DHW, (b) a heating-only boiler + tankless water heater, or (c) a tankless-only setup (for homes with no hydronic heat).

The fundamental difference

A combi boiler is a heating boiler with an added DHW heat exchanger built in — primary purpose is space heating. A tankless water heater is a dedicated DHW device with no space-heating capability. They look similar from the outside (wall-hung, vented through the wall) but inside they are doing different jobs.

If your home has hydronic heating (radiators, radiant floor, baseboard), you need a boiler. The question is whether that boiler should also do DHW (combi) or whether DHW should be a separate device (tankless or tank).

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Setup option 1: Combi boiler (one device does both)

Pros: Single wall-hung unit, lowest install cost, one device to maintain, smaller mechanical-room footprint, shared exhaust vent.

Cons: Hot water flow capped at combi’s GPM rating (typically 4-5.5 GPM in Vancouver winter), no DHW capacity when the boiler is mid-fault, performance degrades as the heating system ages.

Best for: 1-3 bathroom homes, townhouses, condos with hydronic heat.

Setup option 2: Heating-only boiler + tankless

Pros: Each device optimised for its job (highest DHW flow + boiler not stressed by DHW demand), tankless can be replaced independently when it ages, larger total DHW capacity (manifold multiple tankless for very high demand).

Cons: Higher install cost (two devices vs one), more space required, two units to service annually, two warranties to track.

Best for: 4+ bathroom homes, families with simultaneous high-demand showers, larger homes where peak DHW reliability matters more than upfront cost.

Setup option 3: Tankless only (no hydronic heat)

If your Metro Vancouver home has forced-air heating (furnace + ductwork) rather than hydronic, you don’t need a boiler. A standalone tankless water heater handles all your DHW, separate from your heating system. This is the most common setup in newer Vancouver and Burnaby homes.

Cost comparison for Metro Vancouver

Setup	Install cost	Annual operating
Combi boiler (does both)	$9,500–$15,500	$1,400–$2,200 gas (depending on home size and DHW use)
Heating-only boiler + tankless	$13,500–$22,000 (both devices)	$1,400–$2,200 gas (similar)
Tankless only (forced-air home)	$4,500–$6,500 (tankless alone)	$700–$1,100 gas (DHW only, no heating)

What CANRO recommends

If you have hydronic heat AND 1-3 bathrooms: Combi boiler. One device, lowest cost, fits 95% of Vancouver homes in this category.
If you have hydronic heat AND 4+ bathrooms or peak demand issues: Heating-only boiler + tankless. Each device optimised, no DHW compromise.
If you have forced-air heat: Tankless only (or tank). No need for a boiler.

Get the right setup quoted for your home

We will walk through your heating type, bathroom count, and peak demand before recommending an option.

📞 (604) 359-1081 Request a quote

Frequently asked questions

Can I add a tankless water heater alongside my existing combi boiler?

Yes, but rarely worthwhile. If your combi can’t keep up with peak demand, the better fix is usually a buffer tank or a larger combi rather than adding a separate tankless. CANRO will diagnose the root cause first.

Will a tankless water heater work with my existing radiators?

No. Tankless water heaters do not heat space. You need a boiler (combi or heating-only) for radiator or radiant-floor systems.

Which is more reliable: combi or separate boiler + tankless?

Statistically similar. A combi has one device that can fail (taking out both heat AND hot water). Separate boiler + tankless has two devices that can fail independently. Both setups, when properly serviced annually, deliver excellent reliability.

Does CANRO service all combi and tankless brands?

Yes — Navien, Viessmann, IBC, Rinnai, Bosch, Triangle Tube, Laars, Lochinvar, Bradford White, AO Smith, Noritz, Rheem. Common service parts in every truck.

What is a "combi" actually doing differently from a tankless?

A combi has an internal three-way valve that diverts the boiler’s output between space-heating mode and DHW mode. When a tap opens, the combi prioritises DHW. A tankless has no heating circuit — it’s only DHW.

FortisBC rebate — does it favour one setup?

Combi boilers qualify for the boiler rebate ($1,000-$1,500). Tankless water heaters qualify for the tankless rebate ($500-$1,000). A setup with both gets both rebates. CANRO files all applicable paperwork.

CANRO Heating & Cooling — TSBC Class-A gas-fitting licence · Red Seal HVAC certified · WorkSafeBC and liability insured · 4.9★ from 85+ Google reviews · Serving Metro Vancouver since 1999.

Good to know

Frequently asked questions

How often should a boiler be serviced?

Annual servicing is recommended for all residential boilers. CANRO's annual service includes combustion analysis, heat exchanger inspection, expansion tank pressure check, condensate trap cleaning, and a full safety check. Annual maintenance is also required to keep most manufacturer warranties valid.

How much does a new boiler cost in Vancouver?

A typical residential high-efficiency gas boiler in Metro Vancouver costs $7,500–$15,000 installed, depending on size, brand, and whether the system is heating only or a combi unit that also handles hot water. CANRO provides a free written quote with three options at different price points.

How long does a boiler last?

A well-maintained cast-iron boiler can last 25–30 years, a modern high-efficiency condensing boiler typically lasts 15–20 years, and a combi boiler 12–18 years. Annual servicing has the single biggest impact on lifespan.

My boiler is making a banging or kettling noise. Is that dangerous?

Kettling (a banging or whistling sound) is usually caused by limescale build-up on the heat exchanger and is a sign the system is overheating in localised spots. It will not always cause immediate failure but it shortens the life of the boiler and should be addressed within a few weeks.

Do you service Viessmann, IBC, Baxi, Laars, and Weil-McLain boilers?

Yes. CANRO is one of the few HVAC companies in the Lower Mainland with deep experience on European and high-end North American boilers including Viessmann, IBC, Baxi, Laars, Weil-McLain, NTI, Navien and Rinnai. We carry common parts in the truck.

Should I repair or replace my old boiler?

A useful rule: if the boiler is more than 15 years old and the repair cost is more than 50% of replacement, replacement is the better investment. CANRO will give you both a repair quote and a replacement quote and let you decide.

What HVAC services does CANRO offer in Metro Vancouver?

CANRO installs, services and repairs boilers, furnaces, heat pumps, hot water tanks, tankless water heaters, gas fireplaces and air conditioning across Metro Vancouver. We work on residential homes, townhouses and condos throughout the Lower Mainland.

How long has CANRO been in business?

CANRO has been serving the Greater Vancouver area since 1999. Our founder George is recognised by customers as one of the most experienced boiler and hydronic heating technicians in the Lower Mainland.

What areas do you serve?

We cover all of Metro Vancouver: Vancouver, Burnaby, Richmond, Surrey, Coquitlam, North Vancouver, West Vancouver, New Westminster, Delta, Langley, Port Moody, Port Coquitlam, White Rock, Pitt Meadows, and Maple Ridge.

Combi boiler vs tankless water heater

A combi boiler heats your home and produces hot water from one unit, replacing both a furnace and a water heater — best if you're already replacing an aging boiler or furnace. A tankless water heater only heats water, paired with a separate furnace or boiler for space heating — best if your heating system is still in good shape and you just need better hot water. Combi installation runs $6,500-$14,000+ since it covers both functions; standalone tankless installation runs $3,500-$7,500. If one system fails, a combi failure affects both heat and hot water, while a standalone tankless leaves your furnace or boiler unaffected. CANRO's Red Seal technicians (gas licence LGA0043870, boiler licence LBP0046450) can assess your home's layout, hot water demand, and existing equipment to recommend the right fit — ask about the interest-free Canada Greener Homes Loan, CleanBC, and FortisBC incentives that may apply either way. Call (604) 359-1081 for a same-day response.

Tankless water heater vs combi boiler: which one should I choose?

A standalone tankless water heater only heats domestic hot water and costs $3,500-$7,500 installed, while a combi boiler heats your home AND supplies hot water from one unit, running $6,500-$14,000+ installed. Choose tankless if your furnace or boiler is still in good shape and you just need better hot water. Choose a combi boiler if your heating system needs replacing anyway, since combining both functions saves mechanical room space and one appliance replaces two. CANRO's Red Seal technicians hold Technical Safety BC gas licence LGA0043870 and boiler licence LBP0046450 to install and service either option. Ask about the Canada Greener Homes interest-free loan and FortisBC incentives when comparing costs. Call (604) 359-1081 for a same-day response assessment of which fits your Metro Vancouver home.

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What Metro Vancouver homeowners say

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Combi Boiler vs Tankless Water Heater: What’s Best for Your Vancouver Home?

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The fundamental difference

Need help comparing for your specific home?

Setup option 1: Combi boiler (one device does both)

Setup option 2: Heating-only boiler + tankless

Setup option 3: Tankless only (no hydronic heat)

Cost comparison for Metro Vancouver

What CANRO recommends

Get the right setup quoted for your home

Frequently asked questions

Frequently asked questions

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What Metro Vancouver homeowners say

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