Why it matters to the pipes
After the furnace, the water heater is usually the hungriest appliance in the house, and you live with the decision for many years. Choosing between a conventional storage tank and an on-demand tankless unit affects how long showers can last, how much space the equipment takes, how it is vented, and what maintenance it needs.
| Point | Storage tank | Tankless |
|---|---|---|
| Hot water supply | As much as the tank holds, then a wait while it reheats | Continuous, limited by flow rate |
| Space | Large footprint on the floor | Wall-mounted and compact |
| Standby loss | Some heat lost while water sits | Heats only when called |
| Maintenance | Periodic flushing, anode check | Regular descaling and filter cleaning |
| Installation | Straightforward when swapping like for like | May need larger gas line and new venting |
Have to hand
- A flashlight and a bucket
- Old towels and a pair of gloves
- The way to the main valve
Put the tools down if
- Water will not stop at the valve
- Sewage rises in a floor drain
- You smell gas near the heater
The steps, in order
- Count your peak demand. How many showers, baths or appliances run at the same time in the morning?
- Check your gas supply. An on-demand heater pulls a large volume of gas when it lights, and an older, narrow line may not keep up.
- Look at venting. Many tankless and high-efficiency tank units exhaust through the side of the house in plastic flue pipe.
- Think about water hardness. Toronto water is moderately hard, which affects tankless maintenance.
- Consider ownership. Many Toronto homes rent their heater; weigh rental terms against buying.
Common missteps
- Buying a tankless unit sized for an average day rather than winter mornings
- Assuming tankless means no maintenance at all
- Ignoring the cost of new venting or gas pipe when comparing options
- Choosing a tank too small because the old one seemed adequate before the family grew
A realistic picture
Owners who are happiest with tankless heaters tend to be those who value endless showers, need the floor space, and accept yearly descaling. Those happiest with tanks often prefer a simple, familiar system and a straightforward replacement when the time comes. Neither group is wrong. The goal is a heater matched to the household, installed correctly, and maintained on a sensible schedule, so that hot water is the last thing anyone in the house has to think about.
When to ring for help
Bring in a plumber when your current heater is aging or failing and you would like a measured comparison for your specific house. We will look at gas line capacity, venting routes and space, then describe what each option would involve. Ownership is a separate question, handled in a separate guide on whether you should rent or buy a water heater.
While we are in the basement, it can make sense to look at other hidden systems too. A sewer camera inspection is a sensible companion visit for older houses where the drain history is unknown.