To choose a water heater, start with what you have and what your house allows: fuel, venting path, space and electrical capacity. Then size it by your busiest hour, compare lifetime running cost rather than purchase price, check water hardness, outage resilience and rebates, and finish with permits and like-for-like quotes. Natural Resources Canada's advice is to plan before the old tank fails.
- The best choice is usually decided by constraints first: fuel available, venting path, space, drain and electrical capacity.
- Size by first-hour rating or winter flow, never by gallons alone.
- Operating cost over 10–15 years usually outweighs the purchase price; compare with your own energy prices.
- Heat pump water heaters are the most efficient; gas tankless the most compact; atmospheric gas tanks the most outage-tolerant.
- Get quotes that name the model, first-hour rating, venting, expansion control, permit and removal.
01 /What should you decide before choosing a water heater?
Decide on timing and constraints before comparing products. Natural Resources Canada's Water Heater Guide recommends that if your water heater is approaching the end of its expected service life, you research your options now, and it reminds buyers to consider the second price tag: operating costs will be greater than the purchase or rental price. A planned replacement lets you weigh a heat pump, a tankless unit or a different size; an emergency replacement usually means the same thing again.
Work through the twelve steps below in order. Each one either narrows the field or changes the size and cost of what remains.
02 /Steps 1–4: What does your house already have?
- 1. Read your current heater's label
Note the fuel (natural gas, propane, electric), size, venting type (chimney with a draft hood, power vent fan, sealed direct vent), input rating and manufacture date. Open the Tank Explorer if you are unsure which parts you are looking at.
- 2. Check its age and condition
Compare its age with typical service life using the Tank Lifespan Predictor. Signs such as rusty hot water or moisture at the base mean plan now; see signs your water heater is failing.
- 3. List the fuels and capacity available
Is there a gas line to the mechanical room, and could it carry a larger tankless load? Is there a spare 240 V circuit or room in the electrical panel for one?
- 4. Map the venting path
Does the chimney still serve the furnace, or is the water heater alone on it after a furnace upgrade? Is there an outside wall nearby for a sidewall vent? The venting and backdraft guide explains why an orphaned heater on an oversized chimney needs attention.
03 /Steps 5–8: What do you need it to do?
- 5. Size it
Estimate your busiest hour and match it to first-hour rating, or add up simultaneous flow for tankless. The Water Heater Size Calculator does both; the what size water heater guide explains the method.
- 6. Check the space
Heat pump water heaters need room air or ducting, head room and a condensate drain. Tankless units need a wall near a vent route. Tanks need floor space near a drain, and a drain pan over wood floors.
- 7. Compare lifetime running cost
Use the Energy Cost Comparer with your own all-in gas and electricity prices. The gap between technologies is often larger than the gap in purchase price.
- 8. Check your water
Hard water scales tankless heat exchangers and speeds sediment build-up in tanks; softened water can eat anodes faster. See anode rods and flushing a tank.
| Technology | Representative UEF | Example cost per year |
|---|---|---|
| Atmospheric gas tank | 0.62 | about $227 |
| Power vent gas tank | 0.66 | about $213 |
| Condensing gas tank | 0.85 | about $166 |
| Gas tankless | 0.93 | about $151 |
| Electric tank | 0.92 | about $1,063 |
| Heat pump (heated space) | 3.0 | about $326 |
04 /Steps 9–12: What rules, money and paperwork apply?
- 9. Decide how much outage resilience you want
Many atmospheric gas tanks with a standing pilot keep heating during a power outage. Power vent, direct vent with a fan, tankless, electric and heat pump units do not. Natural Resources Canada's guide lists this among the trade-offs.
- 10. Check rebates and financing
Heat pump water heaters attract most incentives; see water heater rebates in Canada. Confirm model and contractor rules before you buy.
- 11. Check permits and who may do the work
Gas work needs a permit and a qualified gas fitter in most of Canada; rules vary. See permits and code.
- 12. Decide rent or buy, then get quotes
If you rent now, read your buyout terms first and compare with the Rent or Buy Calculator. Then get written quotes for the same scope; the installation guide lists what they should include.
05 /Which water heater fits which Canadian household?
Once constraints are known, most households land in one of a handful of patterns. Use this as a sense check, not a verdict.
| Scenario | Usually fits | Watch out for |
|---|---|---|
| Gas-heated house, chimney shared with a mid-efficiency furnace, tank failed | Like-for-like atmospheric gas tank | Chimney condition; permit; CO alarm |
| Furnace upgraded to condensing, water heater now alone on the chimney | Power vent or direct vent tank, or a liner for the chimney | Sidewall termination clearances and snow |
| All-electric home with a warm basement | Heat pump water heater | Drain, space, noise, 240 V circuit |
| Small home or condo, hydronic heat | Combi boiler or indirect tank | Flow limits in winter; see combi and indirect |
| Tight mechanical room, long-term owner, soft to moderate water | Condensing gas tankless | Gas line size, descaling, power needed |
| Big family, frequent simultaneous showers | Larger gas tank or high-input tankless | First-hour rating vs winter flow |
| Rented tank in Ontario near end of life | Check buyout, then compare buying new | Contract terms; see rental vs buy |
If two options remain close, let the tie-breakers be the ones you will live with every day: hot water during outages, noise in the space, and how much routine maintenance you will really do. The types of water heaters and gas vs electric guides go deeper on each technology.
06 /What should the final quote comparison look like?
A fair comparison puts each quote's scope side by side so that price differences can be explained. Natural Resources Canada's Water Heater Guide recommends firm, written bids from several companies and a written contract before work begins, including the manufacturer, model and capacity, warranty details, venting and inspection details, extra parts, removal of the old heater, total cost with taxes, payment method and dates.
| Line | Quote A | Quote B | Quote C |
|---|---|---|---|
| Model, fuel, first-hour rating or flow | |||
| UEF and ENERGY STAR status | |||
| Venting: reuse, reline or new sidewall | |||
| Gas line or electrical work | |||
| Expansion control and T&P discharge | |||
| Permit and inspection included | |||
| Removal of old heater | |||
| Tank warranty and labour warranty | |||
| Rebate eligibility confirmed | |||
| Total with tax |
Then ask each installer the same short set of questions. The answers often explain a price gap better than the totals do:
- Who pulls the permit, and is the fee included?
- Will you check the chimney or vent and the draft after installation?
- Is the system closed, and how will you control thermal expansion?
- What first-hour rating or winter flow will this model deliver for my household?
- What maintenance does this model need, and how often?
- What does your labour warranty cover, and for how long?
- Does this model and your company meet the rebate program's rules?
Be wary of a quote that names no model, leaves out the permit, reuses an old or undersized T&P discharge pipe without comment, or pushes a larger tank without asking how your household uses hot water. Copy those lines into your notes and fill them in as quotes arrive. When you are ready, the quote request lets you describe your current heater and preferred options once, so installers price the same job.
FAQQuestions people ask
What type of water heater is best for a Canadian home?
There is no single best type. Heat pump water heaters are the most efficient, condensing gas tankless units are compact and efficient, and atmospheric gas tanks are the cheapest to replace and often work during outages. Your fuel, venting, space and energy prices decide.
What water heater lasts the longest?
Using the editorial planning ranges in the Tank Lifespan Predictor, tankless units last about 15 to 20 years, electric and heat pump tanks 10 to 15, and gas tanks 8 to 12. Water quality and maintenance shift those ranges.
Should I replace my water heater with the same type?
It is the fastest and usually cheapest option, but Natural Resources Canada suggests considering whether a more efficient choice suits your household before simply replacing like for like.
When is the best time to replace a water heater?
Before it fails, ideally when it nears the end of its expected life. That leaves time to size it properly, compare options, confirm rebates and book a permitted installation.
Do I need a gas fitter to replace a gas water heater?
In most of Canada, yes, and a permit. B.C. allows eligible homeowners to get a homeowner gas permit. Check your province's rules.