Hydro Bill Suddenly Higher? 8 HVAC Things to Check

Bill jumped 30% and you didn't change anything. The HVAC system is responsible most of the time. Run through these.

1. Filter is clogged

The cheapest and most common. A dirty filter forces the blower to run harder + the AC/furnace to run longer. Replace and watch the next bill.

2. Refrigerant low (AC season)

A small leak drops cooling capacity 20–30%. The AC runs almost non-stop trying to hit the setpoint. Symptoms: warm air at the registers when it's hottest out, ice on the line set, hissing near the outdoor unit. Stop running it and call us.

3. Furnace cycling more than usual

If the furnace ignition cycle has changed — burns shorter, restarts faster — see our short-cycling guide. Each cycle wastes ~30 seconds of fuel before useful heat hits the registers. 80 cycles/day instead of 30 = a noticeable bill jump.

4. Thermostat schedule got reset

Power flicker resets older thermostats to 22°C 24/7. Check the schedule. Reprogram for setbacks at night and during work hours.

5. Smart thermostat learning weirdly

Some smart thermostats over-correct: they pre-heat the house aggressively to "guarantee" the setpoint at the right time, using more fuel than just running constantly. Disable "early on" features for one billing cycle and compare.

6. Old or oversized equipment

A 25-year-old 70% AFUE furnace burns 30% more gas than a modern 96% unit for the same heat. An oversized AC short-cycles all summer. Both look like a sudden bill jump after a particularly cold or hot month spotlighting the inefficiency.

7. Duct leakage in unconditioned spaces

Supply ducts running through an attic or crawlspace lose conditioned air to the outside. A 15% duct leak rate is common. Sealing the ducts is one of the highest-ROI energy retrofits.

8. Electric resistance backup engaging on a heat pump

If you have a heat pump with electric backup and it's been very cold, the backup may be engaging more than necessary. Check the thermostat is set to "auto" not "emergency heat" — common mistake after a power flicker.

What to do

Replace the filter, check the thermostat schedule, and book a tune-up if you haven't in 12+ months. We'll measure the actual efficiency and tell you exactly what's costing you.

(416) 258-2460.