In short
- HomeStars' Canada-wide guide puts a thermostat installed at $70–$155 manual, $230–$350 programmable and $200–$500 smart.
- Most smart thermostats draw steady 24-volt power through a common wire (C-wire); without one, an adapter or a new wire adds to the job.
- NRCan says most ducted single-speed heat pumps run on a two-stage heat, one-stage cool thermostat.
- Home Renovation Savings pays $125 toward an eligible smart thermostat (checked 29.10.2026).
Typical prices in Ottawa
| Job | Typical range | Notes |
|---|---|---|
| Manual / programmable / smart thermostat, installed | $70–$155 / $230–$350 / $200–$500 | Canada-wide guide, device and labour |
| New smart thermostat added to other HVAC work | $100–$300 | HomeStars Ottawa HVAC guide |
| Thermostat repair or replacement | $150–$350 | One Ottawa firm’s published list, March 2026 |
| C-wire added where there is none | $90–$135 | Canada-wide guide; extra wire $8–$13 a foot |
| Moving the thermostat | $65–$450 | Canada-wide guide; drywall repair $100–$200 on top |
| HVAC labour, Ottawa | $75–$150 an hour | HomeStars Ottawa guide, average about $110 |
Sources. HomeStars, What Is the Cost of Thermostat Installation in Canada?, updated 21.08.2026, seen 29.10.2026. HomeStars, HVAC Costs in Ottawa, updated 21.08.2026, seen 29.10.2026. One Ottawa firm’s published list: Furnace repair cost Ottawa, published 25.03.2026, seen 29.10.2026. Rebates: Home Renovation Savings, Smart thermostats and Save on Energy, Peak Perks, seen 29.10.2026. Controls: Natural Resources Canada, Heating and cooling with a heat pump, modified 24.12.2025; NRCan, Line voltage thermostats; Resideo Honeywell Home, How do I wire my thermostat?, updated 02.09.2025; ecobee, Power Extender Kit; Carrier Canada, Troubleshooting a furnace, all seen 29.10.2026. Rules and disposal: ESA, Electrical permit education; Ontario, Guide for home renovation and roofing businesses; HRAI, Thermostat Recovery Program; City of Ottawa, Household hazardous waste, all seen 29.10.2026.
Name the system first
A thermostat only switches the equipment behind it, so the request starts with that equipment. Three groups matter:
- Low voltage. Resideo’s wiring guide marks the R terminal as 24 VAC from the heating transformer. Furnaces, central air and ducted heat pumps with a wall thermostat fall here.
- Line voltage. NRCan describes a line-voltage thermostat as a wall unit switching 120 to 240 volts to a baseboard, convector or radiant floor. Resideo says such wiring cannot run a low-voltage thermostat.
- Communicating. Terminals labelled A B C or 1 2 3 point to a system that needs a communicating thermostat.
Put the fuel, the equipment and the number of thermostats in your request, so the fit is confirmed before anyone buys a device.
The C-wire and steady power
A smart thermostat keeps a screen and Wi-Fi running all day, and most models draw that power through a common wire from the furnace or air handler. When the cable at the wall has no spare conductor, there are two routes: an adapter at the furnace, or a new cable. HomeStars puts adding a C-wire at $90–$135 and extra wire at $8–$13 a foot. Ask for the route and its price up front.
Heat pumps, hybrids and backup heat
Stage one of a heat-pump thermostat calls the heat pump; stage two calls the backup when the room keeps cooling. On Resideo’s terminal list, O/B drives the reversing valve, Aux/W2 is the second heating stage and E is emergency heat. Some systems also carry an outdoor thermostat that brings on electric heat in steps or shuts the heat pump off below a set temperature. NRCan notes that programmable heat-pump thermostats can call backup heat only when needed and make that outdoor control unnecessary.
Resideo tells owners of dual-fuel systems to contact a professional HVAC contractor. For a heat pump paired with a gas furnace, see hybrid heating; for wall units with their own controls, see ductless mini-splits.
Where it goes on the wall
Carrier lists a thermostat placed too close to a heat source among the causes of a furnace that turns on and off constantly. A register, fireplace or afternoon sun can skew the reading; see furnace short cycling. Moving a thermostat runs $65–$450 on the HomeStars guide, plus $100–$200 if drywall needs patching.
What moves the price, and what the quote should list
HomeStars’ Ottawa guide puts a new smart thermostat at $100–$300 on top of other HVAC work, and one Ottawa firm lists repair or replacement at $150–$350. The gap comes from who supplies the device, the power route, the system type (a heat pump needs staging and more setup) and any change of location.
The quote should name the model, the wiring work, setup and disposal of the old unit on separate lines, plus HST. In Ontario, home repair work over $50 needs a written agreement, and an estimate can rise by 10% at most unless you sign a change.
Rebates and the old thermostat
Home Renovation Savings pays $125 to an Enbridge Gas customer heating mainly with a gas furnace or boiler, or to a home on the Ontario grid heated or cooled with electricity. Single or semi-detached houses, row or town homes and mobile homes on a permanent foundation qualify; an earlier smart thermostat rebate, discount or device from Enbridge Gas rules you out. Get a code first, or upload the receipt within 60 days. More programs: heat pump rebates in Ottawa.
HRAI says an older thermostat can hold one to four mercury switches of 2.5 grams each, and its free Thermostat Recovery Program takes unwanted mercury-containing and electronic thermostats at public drop-off locations. The City of Ottawa lists mercury switches as household hazardous waste; its next drop-off event is 7 November 2026 at 200 Westbrook Road.
Who handles your request
Ottawa Heating Desk passes your request to one independent local heating and cooling company. That company calls you back, confirms the thermostat fits your system, prices the job and installs it.
Questions to ask the company
- Is my system low-voltage, line-voltage or communicating, and does the model I picked support it?
- Do I have a C-wire? If I need one, will you fit an adapter or run a new wire, and at what price?
- On a heat pump or hybrid, how will the thermostat call the backup heat?
- Will you set the system type and schedule before you leave?
- Will you take the old thermostat for recycling, and can I see the total with HST in writing?
Have this ready for the call
- Brand and model of the thermostat on the wall now, and of the one you want
- What heats and cools the house: gas furnace, boiler, heat pump, hybrid, baseboards, central air
- A photo of the label on the furnace or air handler
- What sits near the thermostat: a register, a fireplace, a sunny window, an outside door
- Your Wi-Fi details for a smart model, and your Enbridge Gas or hydro account if you plan to claim the rebate
Questions people ask
Do I need a C-wire for a smart thermostat?
Most smart models need one for steady power. ecobee’s Power Extender Kit serves homes without a C-wire, but only on 24 VAC systems; it lists millivolt, high-voltage, dual-transformer, fan-coil and communicating units as incompatible. HomeStars puts adding a C-wire at $90–$135.
Can a smart thermostat run my electric baseboards?
Baseboards take a line-voltage thermostat, a different product from a 24-volt furnace control. The Home Renovation Savings list we checked names models for central systems, so check the model before you count on the rebate.
Should I set the heat back at night with a heat pump?
NRCan advises setbacks of 2°C at most, or a smart thermostat that starts the system early. A deep setback can leave the backup heat running until the heat pump catches up.
Will Peak Perks change my heating?
Peak Perks covers central air conditioning, and heat pumps that are part of it. On the hottest summer days, on non-holiday weekday afternoons, the setting moves by no more than 2°C for up to three hours, and you can opt out at any time. Save on Energy pays a $75 virtual prepaid card at sign-up and $20 each year you stay enrolled.
Who may wire a baseboard thermostat?
Line-voltage thermostats switch household current. ESA says only a Licensed Electrical Contractor can be hired for electrical work on a home in Ontario, with the electrical permit listed on the estimate. Ask the company who does that part.
