Is a tankless installed in the same place as my old conventional tank?
Not always.
A tankless water heater can sometimes be installed in the same location as your old storage tank, but it depends on a few important factors.Tankless units are much smaller and can be wall-mounted, which gives more flexibility in placement. However, they often require different venting, gas lines, or electrical capacity than a traditional tank heater. For example, gas tankless systems typically need upgraded gas supply lines and specialized venting, while electric models may require higher-capacity wiring.
Because of these requirements, installers may recommend relocating the unit to a more suitable spot, such as closer to where hot water is most frequently used, or where venting and utilities are easier to accommodate.In short, reusing the same location is possible in some cases, but adjustments or a new placement are often needed to meet installation and efficiency requirements.
What types of tankless systems are there?
There are two main types of tankless water heater systems:
1. Gas Tankless Water Heaters
These units use natural gas or propane to heat water on demand. They’re typically more powerful than electric models and can handle higher water usage, making them ideal for larger households. However, they often require proper venting and may need upgrades to your gas line.
2. Electric Tankless Water Heaters
These systems use electric heating elements instead of gas. They are generally smaller, easier to install, and don’t require venting. Electric models work well for smaller homes or point-of-use applications (like a single bathroom or sink), but may struggle to supply multiple fixtures at once without sufficient electrical capacity.
Some tankless systems are also categorized by how they’re used:
Whole-house systems: Designed to supply hot water to the entire home.
Point-of-use systems: Installed near a specific fixture to provide instant hot water in that location.
Choosing the right type depends on your home size, water usage, and existing utility setup.
Can I expect any savings from a tankless?
Yes, you can expect savings from a tankless water heater but how much depends on your usage and setup.
Tankless systems only heat water when you need it, so they avoid the “standby” energy losses that occur with traditional tank heaters that keep water hot all day. This can lead to improved energy efficiency and lower utility bills over time, especially in homes with moderate hot water usage.
However, the actual savings vary. Smaller households or homes that don’t use large amounts of hot water tend to see the most noticeable efficiency gains. In larger households with high simultaneous demand, the savings may be more modest.
It’s also important to consider the upfront cost. Tankless units typically cost more to purchase and install, especially if upgrades to gas lines or electrical systems are needed. That said, they often last longer than traditional tanks, which can help offset the initial investment over time.
In short, tankless water heaters can reduce energy costs, but the overall savings depend on your household’s water usage, utility rates, and installation requirements.
What is the Cold Water Sandwich?
The “cold water sandwich” is a brief burst of cold water that can occur when using a tankless water heater.
It typically happens when hot water flow is interrupted like when you quickly turn a faucet off and then back on again. When the flow restarts, the heater needs a moment to re-engage and heat the water. During that short delay, a pocket of cooler water can pass through the line, creating a “sandwich” of hot–cold–hot water.
This effect is usually brief and more noticeable in certain situations, such as short, repeated uses of hot water (like washing hands). Many modern tankless systems are designed to minimize this issue, but it can still occur occasionally depending on the system and plumbing setup.
What is a tankless water heater, and what are the advantages?
A tankless water heater also known as an on-demand water heater heats water only when you need it, rather than storing hot water in a tank. When you turn on a hot water tap, the unit quickly heats the water as it flows through the system, delivering a continuous supply.
Advantages of a tankless water heater include:
Endless hot water: Because water is heated on demand, you won’t run out during long showers or back-to-back use.
Energy efficiency: Tankless systems avoid the standby heat loss associated with traditional tanks, which can reduce energy consumption.
Space-saving design: These units are compact and often wall-mounted, freeing up valuable floor space.
Longer lifespan: Tankless water heaters typically last longer than conventional tank models with proper maintenance.
Lower risk of leaks: Without a large storage tank, there’s less chance of major water damage from tank failure.
Overall, tankless water heaters offer a modern, efficient solution for households looking for reliable and continuous hot water.
How much will a tankless cost?
A tankless water heater typically costs between $1,400 and $5,600 installed, with most homeowners paying around $2,500–$3,000 on average.
Several factors can affect the final price:
Fuel type:
Gas systems usually cost more ($2,700–$5,500) than electric models ($1,800–$4,200).
Installation complexity:
Upgrading gas lines, electrical systems, or venting can increase costs.
Home size and usage:
Larger homes or higher water demand may require bigger or multiple units.
While tankless systems have a higher upfront cost than traditional tank heaters, they are more energy-efficient and can lead to lower operating costs over time.
In short: expect a higher initial investment, but potential long-term savings and performance benefits.
What is the hot water sandwich?
The “hot water sandwich” is a brief fluctuation in water temperature that can occur with some tankless water heaters.
It happens when you turn the hot water on, off, and then on again shortly afterward. You may initially get hot water, followed by a short burst of cooler or lukewarm water, and then hot water again like layers in a sandwich.
This occurs because the unit needs a moment to reheat water after the flow restarts, and some cooled water may still be sitting in the pipes between uses.
Modern tankless systems often include features to minimize or eliminate this effect, so it’s usually less noticeable in newer models.
Which would be the most reliable tankless system for a home in Ontario
The most reliable tankless systems for Ontario homes typically come from well-established brands such as Navien, Rinnai, and Noritz. These manufacturers are widely trusted for their durability, efficiency, and consistent performance in Canadian conditions.
For most households, gas-powered condensing units are considered the best overall choice. They handle Ontario’s cold groundwater more effectively and maintain strong hot water flow even in winter.
Navien – Known for high efficiency and advanced features like built-in recirculation systems, making it ideal for larger homes.
Rinnai – Renowned for reliability, strong performance, and a long track record in North America.
Noritz – Offers excellent durability and long warranties, with a reputation for long-term reliability.
Electric tankless units can also be reliable, but they are usually better suited for smaller homes or condos, as they may struggle with high demand during colder months.
In summary, the most reliable system is typically a properly sized gas condensing unit from a top brand, professionally installed to match your home’s water demand and Ontario’s climate conditions.
What sort of venting do I need?
The type of venting you need depends on the kind of tankless water heater you install.
For gas-powered tankless units, proper venting is essential. These systems typically use one of the following:
Direct vent (sealed combustion): pulls air from outside and vents exhaust directly outdoors through a wall or roof.
Power vent: uses indoor air for combustion and vents exhaust outside with the help of a fan.
Condensing units: often use PVC or plastic venting because the exhaust is cooler, making installation more flexible.
Gas models must always vent to the outside to safely remove exhaust gases like carbon monoxide.
For electric tankless units, no venting is required since they don’t produce combustion gases.
Because venting requirements vary by model and home layout, a professional installer should assess your setup to ensure it meets safety codes and manufacturer guidelines.
Can I rent a tankless? How much will it cost?
Yes, you can rent a tankless water heater in Ontario. Many providers offer rental programs with little or no upfront cost, including installation, maintenance, and repairs.
Monthly rental costs typically range from about $50 to $100+ per month, depending on the size and type of system. Lower-end plans may start around $50/month, while higher-capacity or premium units can cost closer to $80–$100/month.
Flow Rate Calculations
Flow rate calculations help determine the right size tankless water heater for your home by estimating how much hot water you’ll need at one time.
To calculate your required flow rate, add up the gallons per minute (GPM) of all fixtures and appliances you expect to use simultaneously. For example, a shower might use 2.0–2.5 GPM, a kitchen faucet around 1.5 GPM, and a washing machine about 2.0 GPM. If you plan to run a shower and a faucet at the same time, your required flow rate would be roughly 3.5–4.0 GPM.
It’s important to size the system based on peak demand rather than average use. Undersizing can lead to insufficient hot water, while oversizing may increase costs unnecessarily.
Keep in mind that incoming water temperature also affects performance colder groundwater requires the heater to work harder, which can reduce the effective flow rate. A professional installer can help refine these calculations to ensure consistent and reliable hot water throughout your home.