Order summary
| Factor | Tank | Tankless |
|---|---|---|
| Hot water supply | Set by the tank's capacity, then recovery time | Endless, but capped by flow rate |
| Space | Floor footprint | Compact, hung on a wall |
| Gas supply | Modest demand | High demand when firing; may need a larger gas line |
| Venting | Chimney or power vent | Dedicated venting to manufacturer specs |
| Maintenance | Annual flush suggested | Periodic descaling suggested |
| Upfront cost | Generally lower | Generally higher |
Numbered steps
- Count the demand. How many showers run at once? Is there a soaker tub? A family that showers back-to-back in the morning stresses a tank differently from a couple.
- Check the gas line. Tankless units draw a lot of gas when running. Many older North York homes have a gas line sized for a furnace and a tank; a tankless unit may need it upgraded.
- Look at venting. A tank may share an existing chimney. A tankless unit typically vents through a side wall, and clearances to windows and doors apply.
- Consider the water. Toronto's moderately hard water leaves scale. Tanks collect sediment at the bottom; tankless heat exchangers scale inside and need descaling.
- Rent or own. Many Toronto heaters are rented. Read the buyout terms of your agreement before replacing anything.
- Plan for the long term. Ask how long each option is expected to last and what service it needs over that time.
Plumber's tip: Before deciding, check the age on your current heater's rating plate and find out whether it is rented. Those two facts shape the next step. To talk it over, call (365) 517-5705.
Errors we see on site
- Choosing tankless without checking the gas supply size.
- Sizing a tankless unit for one shower when two often run together.
- Ignoring the rental contract on the existing tank.
- Skipping maintenance on either type; both lose efficiency to scale.
- Assuming tankless means instant hot water at the tap. Water still travels through the pipes first.
When the desk should come out
Call when your heater is leaking, when it is near the end of its expected life, or when you are renovating and want to change systems. A site visit checks the gas line, venting route and electrical needs so the comparison is based on your house, not a brochure. Related reading: rent or buy a water heater. If the basement also needs water protection, see sump pump installation.
All services are listed on the specialties page.
A note on space and noise
Freeing up floor space is a common reason people look at tankless units, especially in a basement being finished. Keep in mind that a wall-hung unit still needs service clearance and that its fan and burner make some noise when firing. If it will sit next to a bedroom or home office, mention that during the visit so placement can be planned. A tank heater, by contrast, is quiet most of the time but needs a drain nearby and room around the base for the eventual replacement.
Quick checklist
- Count the showers that run at the same time
- Check gas line size before choosing
- Plan for yearly descaling with tankless
Your questions on this one
Does a tankless heater save money?
It can lower standby energy loss, but the higher upfront cost and possible gas line upgrade affect the payback. It depends on your usage.
Can a tankless heater run two showers at once?
If it is sized for that flow rate and the gas supply is adequate, yes. Undersized units drop temperature when demand climbs.