Spring Energy Checklist for Ontario Homes: Prepare for Summer and Save

A spring energy checklist for Ontario homes has three jobs: get cooling equipment ready before the first hot week, find and fix any damage winter left behind, and adjust your habits for the summer electricity schedule that starts on 1 May. Most of the tasks below take an hour or less, and the ones that cost money are mainly routine maintenance that pays for itself in reliability.

Ontario springs are short and unpredictable. It is common to need heat in the morning and cooling by mid-afternoon in May. That makes April and early May the right time to work through this list, before contractors' schedules fill up with no-cool calls.

The spring energy checklist for Ontario homes at a glance

Task	When	Typical cost	Why it matters
Book AC or heat pump maintenance	April to early May	About $100–$250 per visit (estimate)	Catches refrigerant, electrical and drainage problems before peak demand
Clean around the outdoor unit	Once snow melts	Free	Debris and blocked coils reduce efficiency and capacity
Replace or check the furnace filter	Start of cooling season	$10–$50	The same blower and filter serve cooling
Switch the thermostat to cooling mode and update the schedule	Late April	Free	Avoids heating and cooling fighting each other
Review your electricity price plan	Before 1 May	Free	Summer TOU hours differ from winter
Test the sump pump and backup	Early spring thaw	Free to test	Protects the basement during snowmelt and spring rain
Set up the dehumidifier	May	Free	Humid basements cost energy and risk mould
Inspect attic, roof edges and gutters	After snow is gone	Free (DIY)	Finds winter damage and leaks
Check weatherstripping and caulking	Any mild day	$20–$100	Same leaks that let heat out let humid air in
Shut off humidifier and close its bypass damper	When heating stops	Free	Prevents added moisture in summer
Turn off block heater timers and garage heaters	April	Free	Easy to forget, steady electricity use
Reverse ceiling fans to counter-clockwise	Late spring	Free	Pushes air down for a cooling breeze

Get cooling equipment ready

Central air conditioners

• Clear the outdoor unit. Remove leaves, branches and anything stored against it. Keep at least 60 cm (2 ft) of clearance on all sides and nothing overhead that blocks airflow. If you covered the top over winter, remove the cover before switching on.
• Gently rinse the coil with a garden hose from the inside out if you can reach it safely, with power off at the outdoor disconnect. Do not use a pressure washer, which can flatten the fins.
• Check the indoor condensate drain near the furnace. A clogged drain line can flood the basement or shut down the system.
• Book a tune-up with a licensed contractor. Technicians handling refrigerant must hold an Ozone Depletion Prevention (ODP) certificate. Ask them to check refrigerant charge, electrical connections and airflow.

Heat pumps

A heat pump runs all year, so spring is a check-in rather than a start-up. Clear any snow and ice debris from around and under the outdoor unit, confirm the stand is still level, and switch the thermostat from heat to cool (or auto, if you prefer). If your system kept running on backup heat through winter, now is a good time to ask a technician why. Our HVAC maintenance checklist has the full list for each system type.

Tip: Set cooling to around 25–26 °C when home and a few degrees higher when away. Each degree you raise the setting reduces cooling run time, and a ceiling or pedestal fan lets most people feel comfortable at a warmer setting.

Adjust to the summer electricity schedule

On 1 May, Ontario's Regulated Price Plan switches to the summer Time-of-Use schedule. Prices stay the same; the hours change.

TOU period	Winter weekdays (Nov 1–Apr 30)	Summer weekdays (May 1–Oct 31)	Price (from 1 Nov 2026)
On-peak	7–11 a.m. and 5–7 p.m.	11 a.m.–5 p.m.	18.9¢
Mid-peak	11 a.m.–5 p.m.	7–11 a.m. and 5–7 p.m.	14.6¢
Off-peak	7 p.m.–7 a.m.	7 p.m.–7 a.m.	9.1¢

Weekends and holidays remain off-peak all day. Ultra-Low Overnight (ULO) hours do not change with the season, which means the 4–9 p.m. weekday on-peak at 37.7¢ lines up with hot summer afternoons and evenings. On the Tiered plan, the monthly threshold drops from 1,000 kWh in winter to 600 kWh in summer, so heavy air conditioning use can push more of your consumption into Tier 2.

What to change:

• If you work from home on TOU, midday is now the most expensive time. Pre-cool the house in the morning (mid-peak) rather than letting it heat up and cooling hard at 2 p.m.
• Move laundry and dishwasher loads to after 7 p.m. or weekends.
• If you are on ULO with central air, check whether TOU would suit you better for the summer. Our electricity price plan calculator compares all three plans.

Check for winter damage

Attic and roof edges

Look in the attic on a dry day for damp or stained insulation, frost marks on the underside of the roof deck, or daylight around vents and the chimney. Outside, look for damaged shingles, sagging gutters and water staining on soffits. These can point to ice dams, which usually come from warm air leaking into the attic. If you saw icicles or ice dams this winter, see ice dams and attic ventilation. Sealing the air leaks and topping up insulation toward the R-50 to R-60 retrofit target fixes the cause, not just the symptom.

Basement and foundation

• Test the sump pump by slowly pouring water into the pit until the float lifts. Check that the discharge pipe runs well away from the foundation and is not frozen or blocked.
• Look for new cracks, efflorescence (white mineral deposits) and damp patches on foundation walls.
• Check the rim joist area for drafts and insect entry. It is one of the leakiest spots in most Ontario homes and easy to seal with foam board and canned foam.

Windows and doors

Spring is a good time to check weatherstripping, door sweeps and exterior caulking, because damage from winter freeze-thaw cycles is visible. Replace torn weatherstripping and re-caulk gaps around window and door trim. Install screens so you can use natural ventilation on cool evenings rather than running the AC.

Manage humidity before summer

Ontario summers are humid, and basements are where moisture builds. Aim for about 50% relative humidity in summer: low enough to discourage mould and dust mites, without running a dehumidifier constantly.

• Set the dehumidifier humidistat to about 50% rather than its lowest setting. An older dehumidifier running non-stop can use several hundred kWh a month.
• Clean the dehumidifier filter and check the drain hose.
• Turn off the furnace-mounted humidifier and close its bypass damper, if you have one, and replace the humidifier pad before next fall.
• Make sure bathroom fans vent outdoors, not into the attic, and run them for 15–20 minutes after showers.

If you have an HRV or ERV, clean the filters and the core according to the manufacturer's instructions, and check that outdoor hoods are clear.

Other spring tasks worth doing

• Turn off seasonal loads: engine block heater timers, garage heaters, heat tape on pipes or gutters, and heated mats.
• Unplug the spare fridge if it only held winter overflow.
• Check outdoor taps for frost damage once you turn them back on; a split pipe inside the wall may only leak when the tap is open.
• Pool and hot tub start-up: a variable-speed pool pump and a good cover make the biggest difference.
• Plan bigger projects now: spring is a good time to get quotes for insulation, windows or a heat pump before the busy fall season. Check current rebates and programs first; some require approval before work begins.

For the hot months ahead, see our summer cooling savings guide, and bookmark heat wave energy tips for the first extreme heat warning.

Frequently asked questions

When should I switch from heating to cooling in Ontario?

There is no fixed date. Many homes switch in mid to late May, when overnight lows stay above about 10 °C. Until then, opening windows on cool evenings and closing blinds on sunny afternoons often avoids the need for either. Avoid "auto" mode on older thermostats if it causes the system to bounce between heating and cooling.

Should I cover my air conditioner in winter and uncover it in spring?

A breathable cover over the top only can keep falling ice and debris out of a central AC unit over winter, but a full wrap can trap moisture and invite rodents. Never cover a heat pump, which runs all winter. Always remove any cover before turning the AC on.

Is a spring AC tune-up really necessary every year?

For most systems, yes, or at least every one to two years. A tune-up checks refrigerant charge, electrical parts and drainage, and a clean, correctly charged system uses less electricity. It is also far easier to book in April than during the first heat wave.

Does the 1 May TOU change affect my bill if I am on Tiered pricing?

Tiered prices do not depend on time of day, but the monthly threshold for Tier 1 drops from 1,000 kWh to 600 kWh on 1 May. Heavy summer air conditioning can push more usage into the higher Tier 2 price.