Short answer: in Newfoundland and Labrador, there’s no real day when the whole house goes quiet. The closest thing to a pause falls in August, and even then the numbers show a lull rather than a true stop. What changes here isn’t whether you need heat, but how little of it you need, and for how few hours a day.
The quietest month in Newfoundland and Labrador
At the St. John’s A weather station, August comes out as the calmest month on record, with heating and cooling demand together adding up to about 92 degree-days. Across the thirteen provinces and territories this site tracks, that quietest-month figure ranges from roughly 45 up to 233, so a reader in another part of the country can see right away where their own place sits on that scale.
Degree-days aren’t a temperature. They’re a running tally of how far, and for how long, the outdoor air strays from a comfort baseline (18°C in the Canadian system used here). A day that sits right at that baseline adds nothing to the total; a string of cold mornings adds up fast even if the afternoon feels mild. That distinction matters because a reader who reads “92” as a temperature will misjudge Everything that follows.
So is August in St. John’s a real pause, a stretch of weeks where neither system needs to run, or just the seam between two seasons? The total lands toward the lower half of the national range, which points to a genuine lull rather than a straight handoff from heating to cooling. But a lull is not the same as an off switch. This is a province where summer heat almost never asserts itself (more on that shortly), and where cool nights can show up even in the calendar’s warmest weeks. The honest way to put it: August asks less of the house than any other month, but it rarely asks for nothing at all. There’s no window here where a Newfoundland home can be shut down and forgotten the way a milder-summer, harsher-winter province further inland might manage. The lull is real; the full stop isn’t.
Shutting the heat down for the year
One thing to settle before the checklist: over half of Newfoundland and Labrador households, 56 percent, heat with electric baseboard heaters. Another 9 percent run a forced-air furnace, 6 percent a boiler with hot-water or steam radiators, and 8 percent a heat pump. For baseboard homes, “shutting down for the year” barely exists as a task, there’s no filter, no ductwork, no combustion to check. The list below applies mainly to the smaller share running furnaces, boilers, or heat pumps.
The order that avoids trouble
- Turn the thermostat down so the system stops calling for heat, rather than cutting power at the breaker or the switch, which can strand a system mid-cycle.
- Give the equipment time to finish its current cycle and cool down completely before opening anything up.
- For a boiler or furnace, leave the fuel-supply and pilot decisions to the manufacturer’s guidance rather than treating a shutoff as a routine seasonal step.
- Change or clean the filter. As ENERGY STAR puts it: “Inspect, clean, or change air filters once a month in your central air conditioner, furnace, and/or heat pump.” This is a good moment to start that habit for the season ahead, not just close it out.
- If a humidifier is fitted to the ductwork, shut off its water supply and remove the pad. It’s the step almost everyone forgets, and a pad left wet all summer isn’t a pleasant discovery in October.
- Clear vents and registers of anything stacked in front of them over the warm months, and vacuum out visible dust before the system starts working hard again.
One caution that applies directly here: nobody in this province should be told to shut heat off completely for an extended stretch. The mean temperature at St. John’s stays below the 18°C comfort baseline in every single month of the year, including August. Frozen plumbing is a real risk if a house is left with no heat at all for any length of time, so “shutting down” should mean easing back, not switching off.
The first run of the cooling season
Do this check on a mild day, not the first hot one. A mild day gives you time to fix whatever’s wrong before you actually need the system; the first heat wave doesn’t.
What to check, in order
- Clear leaves, grass clippings, and anything else piled against the outdoor unit, and give it a couple feet of breathing room on all sides.
- Check the condensate drain path for blockages, especially after a winter of dust and debris settling in.
- Change or wash the filter, whether that filter serves a central air conditioner, a furnace, or a heat pump, since ENERGY STAR’s monthly-inspection guidance covers all three under one line.
- Run the system in COOL for a full cycle on a mild day, not just a few minutes, so any short-cycling or odd noise has time to show up.
- Feel the air at the register farthest from the unit, not the closest one, since a weak farthest register is the clearest sign of an airflow problem.
That last point matters more than it looks. As ENERGY STAR notes, “Airflow problems can reduce your system’s efficiency by up to 15 percent,” and a system can be running perfectly on paper while still underperforming because a filter or a duct is choking it.
How much this section applies to any one household in Newfoundland and Labrador is worth a caveat. Statistics Canada reports that 58.9 percent of households in the Atlantic region have air conditioning of some kind, against 68.3 percent nationally, and that figure covers the whole Atlantic region rather than this province alone. The survey doesn’t split that number between central systems and portable or window units, so this checklist is written to cover either case. It’s also worth knowing that St. John’s averages zero days a year at 90°F or hotter. A low adoption rate here likely reflects that mild summer more than it reflects an old housing stock, though the source doesn’t say which.
The days that ask for both
Every homeowner recognizes this one even if no thermostat manual explains it: the furnace kicks on at six in the morning, and by three in the afternoon the same room wants cooling. For this site, a month counts as asking for both heating and cooling when it carries at least 50 heating degree-days and at least 50 cooling degree-days. That threshold is a convention set out here for comparing months across the cocon, not a category NOAA or Environment and Climate Change Canada publishes, so don’t mistake it for an official line.
Given that St. John’s logs no days at 90°F or hotter and August, its calmest month, still carries meaningful heating demand, true “both” months are likely rare here in the strict sense: the cooling side of that equation almost never climbs high enough to meet the threshold on its own. What residents actually feel is closer to a heating system that eases off for a few weeks rather than a genuine tug-of-war between two demands.
The practical question that remains is what to do with the thermostat on the cool mornings and mild afternoons in between.
| Setting | What it does | Where it costs you |
|---|---|---|
| Auto changeover | Switches automatically between heat and cool based on the setpoints | A narrow gap between the two setpoints means the system heats in the morning, then cools the same air it just paid to warm, that afternoon |
| Wide deadband | Keeps a several-degree gap between the heat and cool setpoints | Costs comfort on the mildest days, but avoids paying twice for the same air |
| Open windows | Uses outside air instead of either system | Best answer on days when outdoor temperature sits comfortably between both setpoints |
The expensive mistake is the narrow gap: set the heat to kick in at 68°F and the cooling to kick in at 70°F, and the house will run both systems against each other on any day that drifts across that two-degree band.
And the changeover in the other direction
Heating demand at St. John’s doesn’t ease back slowly once August ends, it climbs fast. The monthly totals go from 76 degree-days in August to 172 in September and 329 in October, more than four times over in two months. That pace is the reader’s cue: the reverse changeover, easing off any lingering cooling and getting the heating side ready, needs to happen early in the fall here, not late.
What that changeover looks like depends heavily on what’s actually installed. With 56 percent of households on electric baseboard heaters, most of this province’s pre-season work is as simple as testing each heater and clearing anything stacked in front of it. For the smaller shares on a boiler (6 percent) or a forced-air furnace (9 percent), the checks differ: a boiler calls for bleeding radiators and checking pressure, a furnace calls for the filter and airflow checks already covered above. An 8 percent share runs a heat pump, which carries both a heating and a cooling role and benefits from the filter habit year-round rather than at either changeover alone. Newfoundland and Labrador’s own heating-season guide on this site covers those pre-season steps in more depth; this page’s job is simply to point out when that work needs to start, and here, with degree-days already piling back up by October, the honest answer is sooner than most homeowners expect.