How to Coordinate the Trades on a Conversion
Why this matters
A conversion touches three or four licenses in one house: the electrician for the service and circuits, a gas fitter or plumber for capping lines and checking what stays on gas, the HVAC crew for the heat pump, often a plumber for the water heater. Each trade can do its own part perfectly and the job still fails at a joint between them: a heat pump set on a day the panel is not yet released, a gas line capped by one trade while nobody checks the water heater now venting alone, a house left without heat overnight in November because each crew assumed another had the gap covered.
The fix is not more meetings. It is one named coordinator, handoffs written as observable states rather than dates, and a commissioning list where every whole-house check has a single owner. This article is that mechanism. Why the order runs as it does is owned by the sequence card; this card is how you make several companies actually follow it.
Step 1: Name one coordinator and make every trade report to them
Pick one person, usually from the shop that holds the customer relationship, who owns the calendar, the permit list and the customer's questions. Every other trade reports start, finish and problems to that person, not to the customer. The reason is practical: a customer relaying messages between an electrician and an HVAC tech gets the details wrong and ends up making scheduling decisions they should never have to make.
The coordinator writes down, before anything is booked: which trade holds which permit, which inspections each permit needs, the customer's hard constraints (work hours, pets, a medical need for heat or hot water), and the no-heat plan if the season calls for one.
What breaks if you skip it: two trades book the same day, or none books the gap day, and the customer finds out first.
Step 2: Electrical capacity first, with the release as the handoff
Capacity work goes first because everything else plugs into it. That means the panel or service upgrade if one is needed, or the load management device if that is the chosen alternative, plus the new branch circuits roughed in. The handoff to the next trade is not "electrician finished". It is an observable state: new equipment inspected, released, energized, and each new circuit labeled at the panel with what it feeds.
In many jurisdictions the utility reconnects a new or upgraded service only after the inspector releases it, and the utility's own appointment can take weeks to get. Book the utility and inspection dates before you book any trade that depends on them. See related: The Utility Service Upgrade and Its Timeline.
What breaks if you skip it: the HVAC crew sets a unit on a pad with nothing to connect it to, and either leaves it dead or someone is tempted to feed it from a circuit that was never sized for it.
Step 3: Gas work and venting in the same visit as the appliance removal
When a gas appliance comes out, its branch is capped by the licensed gas trade in that visit, not left open with a valve closed. And the moment any gas appliance comes out, every appliance still on gas changes: a water heater that shared a flue with a furnace may now be on a flue that is too large for it alone. So the gas trade's handoff state is: branch capped, remaining piping tested as your adopted fuel gas code requires for modified piping (Section 406 of the International Fuel Gas Code where that code is adopted, NFPA 54 in the edition your state uses elsewhere), every remaining appliance relit, and a venting and spillage check completed on each one with a CO analyzer, the results written down.
Gas hazard, at this step: if anyone smells gas during the work, everyone leaves the house, nobody operates switches or uses a phone inside, and the call to the utility emergency line is made from outside. See related: How to Cap and Abandon a Gas Line Correctly; What Removing a Gas Appliance Does to the Ones Left.
What breaks if you skip it: the house sleeps one night with a backdrafting water heater, which is the one failure in this whole sequence that can hurt someone.
Step 4: HVAC and plumbing installs, with a no-gap rule
The heat pump and water heater installs come after capacity is live and the gas work is planned around them. Write the no-gap rule into the schedule: in heating season, the furnace is not removed until the heat pump can run the same day, or temporary heat is in place; the old water heater is not removed until the new one will be producing hot water that day, unless the customer agreed otherwise in writing.
When the same crew removes the furnace and sets the heat pump, the gas fitter's capping visit from Step 3 is booked into that same day, so the furnace branch is never left open overnight.
Step 5: Inspections as holds, not afterthoughts
Every permit has inspections that block later work. Rough-in inspections block closing walls or ceilings; a final inspection on the service blocks the utility reconnect; some jurisdictions inspect the gas cap and test before the line is concealed. Put each inspection on the calendar as a hold with the work it blocks written next to it. A trade that closes a wall before rough-in inspection reopens it at their own cost.
The coordination call
Run one short call once permits are in hand and the utility date is confirmed. It is the only meeting the job needs if the handoffs are written down.
OFFICE: Utility can do the cutover on the 14th. Panel
inspection has to be on the 13th or they won't.
ELECTRICIAN: I'll set the new panel beside the old one
the 12th, old service stays live. Inspector's
booked the 13th. Heat pump and water heater
circuits get roughed in from the new panel.
HVAC: Then we set the heat pump the 15th, not before.
Who's capping the furnace branch?
PLUMBER: Me, the 15th, while you pull the furnace. I'll
test the line and do the water heater spill
test before I leave. It's on that flue alone.
OFFICE: Customer works from home, needs heat. Furnace
stays live till your unit runs that afternoon?
HVAC: Yes. If we can't start it, we leave the furnace in
and the plumber doesn't cap.
OFFICE: Then I'll write that down as the rule for that day.
The last two lines are the valuable part: a conditional that ties one trade's action to another's outcome, agreed out loud and written down by the coordinator.
Step 6: Commissioning, with one owner per whole-house check
Each trade commissions its own equipment by its own manufacturer's instructions. What falls between them are the checks that need the whole house running at once. Assign each one a single owner by name:
| Whole-house check | Owner | Done when |
|---|---|---|
| Remaining gas appliances vent and pass a CO check | Gas trade | Readings recorded per appliance |
| All new loads running together, no trip | Electrician | Heat pump, water heater and existing large loads run at once |
| Load management device sheds as configured | Electrician | Shed observed with the trigger load running |
| Thermostat staging, lockout and setback set | HVAC | Values written on the handover sheet |
| CO alarms present where required | Coordinator | Placement confirmed against local rule |
| Customer handover held | Coordinator | Sheet left, follow-up booked |
A check with two owners has none. Each line has exactly one.
Worked example: a schedule that would have failed on day 13
A house is converting furnace and water heater in late October. The first draft schedule was built from each trade's availability: electrician on the 12th, HVAC on the 13th, plumber for the water heater and gas caps on the 16th, inspection "when the inspector can come".
The coordinator checked it against the handoff states. The electrician was setting the new meter base and panel beside the old service, which stays live until the utility cuts over, and the utility could only cut over on the 14th, after an inspection that had to happen on the 13th. The heat pump's circuit lives in the new panel. Under the draft, the HVAC crew would arrive on the 13th to a circuit with no power behind it for at least another day. They would remove the furnace as booked with nothing able to heat the house, and with the plumber not coming until the 16th, the furnace branch would sit valved off but uncapped for three nights, and the water heater would vent alone on the oversized flue from the 13th until somebody checked it.
The corrected schedule is the one in the call above: new panel on the 12th, inspection on the 13th, cutover on the 14th (the house is without power only for the utility's cutover window, which the customer was told about), heat pump, furnace removal, cap, test and water heater spill test all on the 15th, with the furnace staying live if the heat pump cannot start. Two days later than the draft's heat pump date, and no night without heat, an uncapped branch or an unchecked water heater.
What changes the answer: if no service work is needed, Step 2 shrinks to circuits and the HVAC date can move up; if the house will keep a gas water heater for years, its venting fix (a liner or a new vent) becomes its own scheduled item rather than a check. A summer conversion relaxes the no-heat rule but not the venting check.
How to verify the coordination held
At close-out, the coordinator should be able to produce, without calling anyone: the inspection approvals, the gas test record and the venting and CO readings for each remaining appliance, the panel labels, and the completed commissioning table with a name on every line. A missing record is a missing check. Then add the job to the customer's file so the next tech finds it. See related: How to Document a Converted House for the Next Tech.
References
- See related: The Whole-House Electrification Sequence
- See related: The Service Upgrade Coordination SOP
- See related: Combustion Safety After a Partial Conversion
- International Fuel Gas Code, Section 406 (inspection, testing and purging), or NFPA 54, in the edition adopted by your jurisdiction
- Equipment manufacturer installation and commissioning instructions for each installed appliance