Installing a tankless water heater, gas fireplace, or pool heater? Learn why
Ontario requires a gas load calculation to ensure your gas piping can safely supply the new
appliance.
Why Every New Gas Appliance Requires a Gas Load Calculation
Installing a new gas appliance isn’t as simple as connecting it to your existing gas line.
Whether you’re upgrading to a tankless water heater, installing a gas fireplace, adding a pool heater, or replacing your furnace, every new appliance changes the total gas demand on your home’s piping system.
At ER Plumbing & Heating, one of the first things we do before installing a new gas appliance is perform a gas load calculation to ensure your gas piping system can safely and reliably supply enough natural gas to every appliance in your home.
What Is a Gas Load Calculation?
Every gas appliance has a rated input measured in BTUs (British Thermal Units). When you add another appliance—or replace one with a larger model—the total gas demand changes.
A licensed gas technician must calculate:
• The BTU input of every connected appliance
• The total system demand
• The length of each gas piping run
• The pipe size throughout the system
• The available gas pressure
These calculations determine whether the existing gas piping can safely carry the required volume of natural gas.
Why Tankless Water Heater Upgrades Often Require Larger Gas Piping
A conventional storage water heater typically requires approximately 40,000–50,000 BTU/hr. A whole-home tankless water heater may require 180,000–199,000 BTU/hr—often four to five
times the gas demand of the appliance it’s replacing. If the existing gas piping was designed for the original appliance, it may no longer be adequate.
What Happens If the Gas Line Is Too Small?
Undersized gas piping can lead to poor appliance performance, ignition failures, equipment
error codes, reduced heating capacity, excessive wear, appliance shutdowns, and unsafe operating conditions.
It's About More Than One Appliance
Gas systems must be designed to operate when multiple appliances run at the same time. A furnace, tankless water heater, gas range, clothes dryer, fireplace, and pool heater may all operate simultaneously. Your gas piping must be capable of supplying every appliance under peak demand conditions.
Ontario Code Requirements
Ontario’s gas safety regulations require licensed gas technicians to verify that gas piping is
properly sized for the connected appliance load. If calculations show the piping is undersized,
modifications such as larger piping, dedicated gas lines, or manifold changes may be required
before the appliance is placed into service.
Trust ER Plumbing & Heating
Whether you’re installing a tankless water heater, gas fireplace, furnace, pool heater, boiler,
barbecue connection, or another natural gas appliance, ER Plumbing & Heating performs the
necessary gas load calculations before beginning the installation. As licensed gas contractors
serving Windsor and Essex County, we don’t guess—we calculate.
