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Gas Fitting · CapacityGas Line Upgrade & Upsizing
A gas line upgrade — upsizing — is needed when the appliances on a pipe can burn more gas than the pipe can deliver, and the test is a number: the inlet pressure at the farthest appliance, measured with everything firing. If that reading sags below what the rating plate asks for, the fix is a larger trunk, a dedicated run from the meter or a 2 psi system. Upsizing a single undersized run for a tankless water heater costs $400–$1,200; larger jobs are quoted after a load calculation.
Most houses in Halton and Hamilton were piped for two appliances: a furnace and a tank water heater, together somewhere near 100,000 to 150,000 BTU an hour. A tankless water heater alone can be rated at 199,000 BTU. A pool heater is commonly 250,000 to 400,000, a standby generator is in the same league, and a gas range adds its own load. The half-inch branch that fed the old tank was never meant for any of them.
Undersized piping rarely announces itself as a gas problem. It shows up as a tankless heater that throws an ignition or flame-loss code when the furnace is running, range burners that shrink when the dryer starts, or a pool heater that locks out on the first cold evening of May. We confirm it with a manometer on the appliance's inlet tap, reading the pressure at rest and then with every appliance in the house firing. Natural gas reaches most houses at about 7 inches of water column, roughly a quarter of a psi, so there is very little to lose along the way.
There are three ways to fix it, and the load calculation picks one. Upsizing the trunk replaces the starved section with larger pipe and suits a house where one main feeds everything. A dedicated run takes a new line from the meter straight to the big appliance and leaves the existing piping alone, which is usually the least disruptive answer in a finished basement. A 2 psi system raises the pressure at the meter so small-diameter pipe can carry a large load over a long distance, with a regulator at each appliance or manifold stepping it back down.
The calculation adds the rating-plate input of every appliance, measures the developed length to the farthest one and reads the pipe size off the tables in CSA B149.1. It also checks the meter, because a meter has a badge capacity of its own and bigger pipe downstream does nothing if the meter is the bottleneck. When the total exceeds the meter, or the design calls for 2 psi delivery, we send the load details to Enbridge Gas and the utility schedules the change. The tankless case has its own page: does a tankless water heater need a bigger gas line.
Signs the gas line is too small
- A tankless water heater faults or goes lukewarm whenever the furnace is running
- Range flames drop visibly when another gas appliance starts
- You are adding a pool heater, standby generator, garage heater or second furnace
- A technician has measured low inlet pressure at an appliance under load
- The quote for a new appliance says the existing half-inch branch has to be replaced
How it works
We record the BTU input from every rating plate, including the appliance you plan to add, and compare the total with the meter's capacity. You see the arithmetic, not just the conclusion.
Pipe sizes and lengths are measured, inlet pressure is read under full load, and the design is chosen: larger trunk, dedicated run or 2 psi with regulators. If Enbridge has to change the meter, the request goes in before pipe is ordered.
The new pipe is installed and pressure-tested, appliances are reconnected and relit, and the inlet pressure is measured again with everything firing. That second reading goes on your invoice; to book the first one, contact us.
Common questions
How do I know the gas line is undersized and not the appliance?
By measuring. A manometer on the appliance's inlet tap shows the pressure with the burner off and then with every gas appliance running. If the reading holds, the fault is in the appliance; if it drops below the minimum printed on the rating plate, the piping or the meter cannot keep up with the connected load.
What is a 2 psi gas system?
It is house piping run at 2 pounds per square inch instead of the usual quarter psi, which lets a small pipe carry a large load. Each appliance, or a manifold serving several, gets a line regulator that drops the pressure back to what the burner expects. It needs a 2 psi meter set from Enbridge and regulators left accessible.
Will Enbridge charge to upgrade my meter?
That is the utility's decision, based on the added load and the existing service, and it can change, so we do not quote it for them. We prepare the load summary, submit the request and tell you what Enbridge comes back with before you commit to the piping work.
Can I add a pool heater to the line that feeds my barbecue?
Almost never. A barbecue branch is sized for a small burner load and a pool heater needs several times that, usually at the far end of the yard. A pool heater normally gets its own run from the meter, sized for the distance; the appliance side is covered under pool heater installation.
Is upsizing different from a new gas line?
Yes. Upsizing replaces or supplements piping that already serves appliances because the load has outgrown it. A new line extends gas to a place that never had it, such as a deck or a garage, and is covered under gas line installation. Many jobs involve both, and one load calculation covers the two.