Tank, Tankless or Heat Pump: Choosing a Water Heater
Three technologies, three completely different installations. Most of the decision is made by what your house already has, not by which unit is best on paper.
Water heaters get replaced under pressure. The tank fails on a Sunday, there is water on the mechanical room floor, and the homeowner has about an hour to decide between the thing that was already there and something different. That is a bad moment to be learning what a condensing tankless unit needs for venting.
This guide is written for the calmer version of that decision, when a tank is 10 years old and still working. Read it before you need it, and the conversation with a licensed plumber in Surrey becomes a short one about sizing and scheduling rather than a scramble.
The Three Options Side by Side
| Conventional tank | Gas tankless | Heat pump (hybrid) | |
|---|---|---|---|
| How it works | Heats and stores a fixed volume, keeps it hot around the clock. | Fires on demand and heats water as it passes through a heat exchanger. No storage. | Moves heat out of the surrounding air into a storage tank using a compressor. |
| Upfront cost | Lowest. | Higher, and the gap widens if gas or venting work is needed. | Highest before rebates, and rebate programs change the picture significantly. |
| Running cost | Standby losses run continuously. | No standby loss. Efficiency depends on how the household draws hot water. | Lowest energy use of the three in a mild climate. |
| Hot water supply | Finite. Run the tank down and you wait for recovery. | Continuous, but limited by flow rate. Two simultaneous showers can outrun an undersized unit. | Finite like a tank, with slower recovery in heat pump mode. Most units have an electric backup element. |
| Space needed | Floor footprint, standard closet or mechanical room. | Wall mounted. Frees up floor area, which matters in a townhome. | Tall, and needs surrounding air volume to draw heat from. Not a sealed closet. |
| Typical service life | Roughly 8 to 12 years. | Longer, with descaling and maintenance as a condition of that. | Comparable to a tank, with a compressor as an additional component. |
What Each One Actually Needs From Your House
Conventional tank
The like-for-like swap. Existing venting, gas or electrical, and connections usually carry over. In British Columbia the unit needs seismic restraint, and if there is a check valve or pressure reducing valve on the service, the system is closed and thermal expansion has to be handled. If your current tank has no expansion tank and the T&P valve keeps discharging, that is the reason.
Gas tankless
The two costs people do not anticipate are gas supply and venting. A tankless unit fires at a much higher input than a tank, so the existing gas line is often undersized and needs to be upsized back to the meter. Condensing units also require their own sealed venting and a condensate drain, which the old B-vent will not satisfy. None of this is a reason to avoid tankless. It is a reason to have the installation scoped before you buy the unit.
Heat pump water heater
These work by pulling heat out of the air around them, so they need volume, not a tight closet. A garage or a generously sized mechanical room is ideal. They also produce condensate that needs a drain, they cool and dehumidify the space they sit in, and they need a suitable electrical circuit. The Lower Mainland's mild climate is close to ideal for this technology, since ambient air temperatures rarely drop low enough to push the unit onto its backup element for long.
Check the rebates before you commit. Efficiency rebates in British Columbia are offered through FortisBC, BC Hydro and CleanBC programs, and the amounts, eligible equipment and application deadlines change from year to year. They can move a heat pump water heater from the most expensive option to a competitive one. Confirm current program terms before you order equipment, and check whether the rebate requires a licensed contractor and a permit, because most do.
Sizing Matters More Than Brand
An undersized unit of any type produces an unhappy household, and an oversized one wastes money. The measurements that matter:
- Tanks: first hour rating. How much hot water the unit can deliver in one hour starting full, which is a better guide than raw tank volume.
- Tankless: flow rate at your temperature rise. A unit rated for a given number of litres per minute delivers that rate at a specific temperature rise. Incoming water here is cold for much of the year, so the real-world flow rate is below the number on the box.
- Simultaneous demand. Count fixtures that get used at once. Two showers plus a dishwasher is a different sizing problem than one bathroom.
- Recovery rate. For a household that showers back to back in the morning, recovery speed matters more than storage volume.
Signs Your Current Tank Is Near the End
Rusty or cloudy hot water
Discoloured water on the hot side only usually points at the tank interior, not the supply.
Rumbling or popping
Sediment on the tank bottom boiling under the burner. It insulates the base, hurts efficiency and stresses the tank.
Water around the base
If it is coming from the tank body rather than a fitting, the tank is finished. There is no repair for a perforated tank.
Falling recovery
Showers that used to be fine now run cold, with nothing else in the house changed.
Tank leaking now? Shut off the cold inlet valve above the tank and the gas or breaker, then call (778) 562-5628. Same day replacement is often possible.
A Short Decision Path
- Replacing under emergency conditions, gas already there: a like-for-like tank is almost always the right call. Do not make a technology change while standing in water.
- Planned replacement, tight on floor space, gas service adequate: tankless earns its keep, especially in a townhome or a suite conversion.
- Planned replacement, garage or large mechanical room, rebate available: a heat pump unit is the strongest long-term running cost, and the local climate suits it.
- Electric-only home with no gas service: the real comparison is a conventional electric tank against a heat pump unit, and the heat pump usually wins on operating cost.
Get the Sizing Done Before the Tank Fails
Book an inspection and a technician will assess your current setup, check gas, venting and electrical capacity, and give you real options with pricing rather than a guess over the phone. The $60 inspection fee is credited toward the work once you approve the quote.
See water heater services for repair and replacement details, or visit WaterLine Plumbing for the full service list.
Common Questions
Does a tankless unit really never run out of hot water?
It never runs out of stored volume, because there is no storage. It can still be outrun on flow. If two showers and a tap are open at once and the unit is sized for less, everyone gets lukewarm water at the same time. Sizing is what makes the promise true.
Do tankless units need maintenance?
Yes. Periodic descaling of the heat exchanger is part of ownership, and many manufacturer warranties expect it. Our water is very soft, which helps considerably compared with a hard-water region, but the service interval is still real.
Will a heat pump water heater make my garage cold?
It will cool and dehumidify the space it draws from. In a garage that is usually irrelevant or mildly useful. In a small interior closet it is a problem, which is why placement is part of the assessment rather than an afterthought.
Is a permit required to replace a water heater?
Permit requirements depend on the scope of the work and the equipment involved. The City of Surrey publishes plumbing permit information and applications online, and gas fitting has its own requirements under Technical Safety BC. Ask before the work is scheduled, not after.
References
- Province of British Columbia, BC Plumbing Code 2024. Retrieved from gov.bc.ca.
- City of Surrey, Online Plumbing Permit Applications. Retrieved from surrey.ca.
- SkilledTradesBC, Plumber trade certification. Retrieved from skilledtradesbc.ca.