RenoNextRenoNext
CallBook your walkthrough
Licensed, Insured & WSIB Covered

HVAC

Oversized furnaces short-cycle and waste energy — Manual J load calculations size equipment right, not "rule-of-thumb" guesses.

Written by Pavel Vysotckii

BCIN-certified building designer & Quantity Surveyor · Updated June 2026

Get a Price EstimateBook your walkthrough

Project Overview

Timeline
1 day for furnace/AC replacement, 2-3 days for heat pump + ductwork modifications, 3-5 days for whole-home HVAC install
Difficulty
Licensed HVAC technician required. Gas work needs TSSA certification. Refrigerant handling requires EPA 608 certification.
Starting at
$2,500-$4,500
Best Season
Shoulder seasons (spring/fall) offer best availability and pricing. Winter furnace failures and summer AC failures create emergency pricing and 1-2 week waits.

Fixed Milestone Pricing

You approve each stage before it's paid

Overview

What is hvac?

HVAC systems move heat — heating adds heat to indoor air, cooling removes heat from indoor air. Thermodynamics says heat flows from hot to cold, so both require energy to force heat the "wrong" direction.

Furnaces burn fuel (natural gas, propane, oil) to heat air. AFUE (Annual Fuel Utilization Efficiency) measures efficiency: 96% AFUE means 96 cents of every dollar goes to heating, 4 cents up the flue. Mid-efficiency furnaces (80-85% AFUE) vent through chimneys. High-efficiency furnaces (90-98% AFUE) extract so much heat that exhaust condenses — they need PVC vents and condensate drains.

Air conditioners and heat pumps use refrigerant to move heat. AC removes heat from inside and dumps it outside. Heat pumps reverse the cycle — in winter they extract heat from outdoor air (even at -15°C, air contains heat) and pump it inside. Coefficient of Performance (COP) measures efficiency: COP 3.0 means 3 kWh of heat for every 1 kWh of electricity. Heat pumps deliver 2-4x more heat per kWh than electric baseboards.

SEER (Seasonal Energy Efficiency Ratio) measures cooling efficiency. SEER 16 is current minimum, SEER 20+ is high-efficiency. SEER2 is the new 2023 standard (slightly lower numbers, more realistic testing). Cold-climate heat pumps maintain COP 2.0+ at -25°C — older heat pumps lose efficiency below -10°C and need backup heat.

Ductwork sizing matters. Undersized ducts restrict airflow, causing whistling, hot/cold spots, and reduced efficiency. Oversized ducts reduce velocity, causing poor distribution and stratification (hot air at ceiling, cold at floor). Manual D calculations size ducts based on airflow (CFM) and static pressure.

When you need hvac

  • Furnace replacement — yellow flame (should be blue), cracked heat exchanger (carbon monoxide risk), age 15+ years, or repeated repairs exceeding 50% of replacement cost
  • Air conditioner replacement — age 12+ years, refrigerant leaks (R-22 costs $100+/lb and is phased out), compressor failure, or SEER below 13 (wastes energy)
  • Heat pump installation — replacing electric baseboards, oil furnace, or propane (heat pumps cost 50-75% less to operate than electric resistance heating)
  • Ductwork modifications — adding rooms, finishing basement, converting to heat pump (may need larger supply/return ducts for increased airflow)
  • Heating/cooling capacity issues — rooms too hot/cold, system runs constantly, high energy bills, ice on AC coil, furnace short-cycling
  • Indoor air quality — adding HRV/ERV (heat recovery ventilator), whole-home humidifier/dehumidifier, HEPA filtration, UV air purifier
  • Thermostat upgrade — replacing mechanical with programmable or smart thermostat (Ecobee, Nest) for scheduling and remote control
Step by Step

The Process

What happens from start to finish

1

Manual J Load Calculation

1-2 hours

HVAC contractor calculates heating/cooling loads room-by-room using Manual J methodology. Inputs: square footage, insulation R-values, window area/orientation, air leakage (blower door test), occupancy, lighting, appliances. Output: total BTU/hr heating and cooling loads. Proper sizing prevents oversized equipment (short-cycling, poor humidity control) and undersized equipment (never reaches setpoint).

2

Equipment Selection & Proposal

1-2 days

Contractor recommends equipment based on load calc, fuel source, budget, and efficiency goals. Furnace: AFUE rating (80%, 92%, 96%), single-stage vs two-stage vs modulating. AC/heat pump: SEER/SEER2 rating, single-stage vs variable-speed, cold-climate performance. Provides itemized quote: equipment, labor, ductwork mods, permits, disposal, warranty.

3

Permitting & Utility Coordination

1-4 weeks

Contractor pulls HVAC permit (TSSA for gas work, municipal for AC/heat pump). Schedules gas disconnection if replacing furnace (TSSA requires shut-off during install). Orders equipment (2-4 weeks lead time for heat pumps). Coordinates electrical if heat pump needs dedicated 240V circuit or panel upgrade.

4

Installation & Ductwork Modifications

1-3 days

Contractor removes old equipment, installs new furnace/AC/heat pump, connects ductwork, runs refrigerant lines (heat pump), installs condensate drain, wires thermostat, tests airflow and pressures. Ductwork mods: resizing supply/return registers, sealing leaks (30% of conditioned air leaks in typical duct system), balancing dampers, adding returns (poor return airflow kills efficiency).

5

Startup, Commissioning & Inspection

Half day

Contractor performs startup: checks refrigerant charge (AC/heat pump), combustion analysis (furnace CO and efficiency), airflow CFM, temperature rise/drop, thermostat programming. TSSA inspects gas connections and venting. Municipal inspector verifies refrigerant certification and electrical connections. Contractor demonstrates system operation and maintenance (filter changes, condensate drain clearing).

Pricing Transparency

Investment Guide

HVAC pricing depends on equipment efficiency (AFUE, SEER), capacity (BTU, tonnage), installation complexity (ductwork mods, electrical upgrades), and permits. High-efficiency equipment costs more upfront but saves 30-50% on energy bills.

Gas furnace replacement (80% AFUE, 60K-100K BTU)

$2,500-$4,500

Depends on: Mid-efficiency furnace, standard venting (chimney), includes labor, permit, disposal. High-efficiency (92-96% AFUE) adds $1,500-$3,000 for condensing unit and PVC venting.

Central air conditioner (2-3 ton, SEER 14-16)

$3,000-$5,500

Depends on: Includes outdoor condenser, evaporator coil, refrigerant, labor, permit. SEER 18-20 adds $1,000-$2,000. Add $500-$1,500 if ductwork needs resizing or sealing.

Air-source heat pump (cold-climate, 2-3 ton)

$5,000-$10,000

Depends on: Includes outdoor unit, indoor air handler, refrigerant lines, labor, permits. Cold-climate models (Mitsubishi, Fujitsu, Carrier Greenspeed) cost more but work to -25°C. Ducted systems cost more than ductless mini-splits.

Furnace + AC combo (high-efficiency)

$6,000-$10,000

Depends on: 96% AFUE furnace + SEER 16 AC, includes both units, labor, permits, disposal. Two-stage or modulating furnace adds $1,000-$2,000. Variable-speed AC adds $1,500-$3,000.

Ductwork replacement (whole-home, 1,500 sq ft)

$3,000-$8,000

Depends on: Includes Manual D sizing, trunk-and-branch layout, insulated flex or rigid duct, registers, dampers, sealing. Basement ducts cost less than attic runs (access).

HRV/ERV installation (heat recovery ventilator)

$2,000-$4,500

Depends on: Includes HRV unit (150-200 CFM), ductwork tie-in, fresh air intake, exhaust vent, labor, permit. ERV (energy recovery) adds humidity control, costs $500-$1,000 more.

Permits
Permit Required
TSSA Gas Permit$50-$150
HVAC Mechanical Permit$100-$300
Electrical Permit (if applicable)$88-$200

What Affects the Price

Efficiency ratings — 96% AFUE furnace costs $1,500 more than 80% AFUE but saves $300-$500/year on gas bills. SEER 18 AC costs $1,500 more than SEER 14 but saves $150-$300/year on electricity.Capacity sizing — oversized equipment short-cycles (poor humidity control, wasted energy, faster wear). Manual J load calc prevents oversizing. Never use "rule-of-thumb" (1 ton per 500 sq ft) — it ignores insulation, windows, air leakage.Ductwork condition — 30% of conditioned air leaks in typical duct systems. Sealing ducts (mastic, not tape) improves efficiency by 20-30%. Undersized ducts restrict airflow — resizing costs $500-$2,000 but prevents hot/cold spots.Refrigerant type — R-22 (Freon) is phased out, costs $100+/lb. New systems use R-410A (20-30% more efficient). If your AC needs refrigerant, replace the system — leaks mean the coil is corroded.Two-stage vs modulating — single-stage furnaces run full-blast (noisy, temperature swings). Two-stage runs 60-70% capacity most of the time (quieter, better comfort). Modulating adjusts 40-100% in 1% increments (best comfort, 10-15% more efficient).Heat pump backup heat — cold-climate heat pumps work to -25°C but lose efficiency below -10°C. Backup heat (electric coils or dual-fuel gas furnace) covers extreme cold days. Electric backup adds $500-$1,000, dual-fuel adds $2,000-$4,000.

Get instant HVAC pricing from licensed contractors. Upload photos of your existing equipment and describe your heating/cooling issues — we'll match you with TSSA-certified technicians and show real project costs.

Get a ballpark estimate in under 2 minutes.

Try Price Check
Detailed cost breakdown with city-by-city pricingFree contract template for this service

Permits & Building Code

Ontario Building Code requirements

Permit / ApprovalAuthorityTypical Cost
TSSA Gas PermitTechnical Standards & Safety Authority$50-$150
HVAC Mechanical PermitMunicipal building department$100-$300
Electrical Permit (if applicable)ESA (Electrical Safety Authority)$88-$200

TSSA inspects gas furnaces for proper venting (flue draft, no leaks), combustion efficiency (CO levels), and gas line sizing. High-efficiency furnaces need PVC venting and condensate drains.

Refrigerant handling requires EPA 608 certification (Ontario follows federal standard). Inspectors verify contractor certification and check for refrigerant leaks.

Ductwork leaks waste 20-30% of conditioned air. Inspectors may require duct sealing (mastic, not tape) and insulation on ducts in unconditioned spaces (attics, crawlspaces).

Cracked heat exchangers leak carbon monoxide into supply air — #1 cause of CO poisoning from furnaces. TSSA fails furnaces with visible cracks or CO in supply ducts. No shortcuts.

How You Pay

Fixed Milestone Pricing, Approved by You

Every hvac project runs on fixed milestone pricing. The plan is signed before work starts, and you approve each stage before it's paid.

  • Plan Signed Before Work Starts

    Every milestone and its price is written into the contract up front — no surprise extras.

  • Review in the Live App

    Daily photos, inspection reports, and spend vs budget land in your client app at every phase.

  • You Approve Each Milestone

    A stage is only paid after you review the work and sign off in the app.

Book your walkthrough

Project Center

HVAC

In Progress
Deposit15%
Equipment Selection & Proposal25%
Permitting & Utility Coordination30%
Final + Holdback30%

Milestone Progress

Milestone 3 of 4

Approved by you

Reduce your cost — see available rebates and incentives

GTA homeowners can stack federal, provincial, and municipal programs for significant savings.

HVAC Failures — Why Bad Systems Waste Money and Kill

  • Cracked heat exchangers leak carbon monoxide into supply air — #1 silent killer from furnaces. CO is colorless, odorless, and fatal at 400 ppm (headache at 70 ppm). TSSA fails furnaces with visible cracks. Install CO detectors on every floor.
  • Oversized equipment short-cycles — runs 5 minutes, shuts off, repeats. Poor humidity control (AC doesn't run long enough to dehumidify), temperature swings, wasted energy, faster wear. Manual J load calc prevents oversizing. Never trust "1 ton per 500 sq ft" rule.
  • Ductwork leaks waste 20-30% of conditioned air — you're heating/cooling your attic or crawlspace. Seal ducts with mastic (not tape, tape fails in 5 years). Insulate ducts in unconditioned spaces (R-6 minimum).
  • Refrigerant leaks mean the coil is corroded — topping off R-22 costs $300-$600 and buys 1-2 years before it leaks again. Replace the system. R-22 is phased out, costs $100+/lb, and availability is declining.
  • Missing return air kills efficiency — single return in hallway creates negative pressure in bedrooms, restricts airflow, causes hot/cold spots. Add return vents in every room or undercut doors 1" (allows air to flow back to return).
  • Dirty filters double energy bills — clogged filter restricts airflow, forcing blower to work harder and reducing heat transfer. Change filters every 1-3 months (1" filters monthly, 4" filters quarterly). Set phone reminder.
  • DIY refrigerant work is illegal and dangerous — refrigerant requires EPA 608 certification. Overcharging damages compressor ($1,500-$3,000 replacement), undercharging kills efficiency. Let licensed techs handle refrigerant.

Trusted by Ontario Homeowners

One licensed crew and a live client app on every hvac project

Licensed

OBC Licensed, Insured & WSIB Covered

Live App

Daily Photos & Inspection Reports

Fixed Price

Milestones You Approve

Related Services

Electrical

Heat pumps and electric heating need dedicated circuits and may require a panel upgrade.

Learn more

Insulation

Upgrading insulation reduces your heating/cooling load — do it before sizing new HVAC equipment.

Learn more

Plumbing

Boiler systems, in-floor radiant heat, and water heaters overlap with HVAC work.

Learn more
FAQ

Common Questions

What size furnace or AC do I need?
Proper sizing requires Manual J load calculation — room-by-room heat loss/gain based on insulation, windows, air leakage, orientation. "Rule-of-thumb" (1 ton per 500 sq ft) ignores these factors and oversizes equipment by 30-50%. Oversized furnaces short-cycle, waste energy, and wear faster. Pay for Manual J load calc ($150-$300) before buying equipment — it saves thousands in wasted energy.
What's the difference between 80% and 96% AFUE furnaces?
80% AFUE = 80 cents of every dollar goes to heating, 20 cents up the flue. 96% AFUE = 96 cents to heating, 4 cents up the flue. High-efficiency furnaces extract so much heat that exhaust condenses — they need PVC vents (not chimney) and condensate drains. Costs $1,500-$3,000 more upfront but saves $300-$500/year on gas bills. Payback: 5-7 years.
Are heat pumps worth it in Ontario winters?
Yes, if you buy a cold-climate model (Mitsubishi, Fujitsu, Carrier Greenspeed). Cold-climate heat pumps maintain COP 2.0+ at -25°C — they deliver 2 kWh of heat for every 1 kWh of electricity. Electric baseboards deliver 1:1. Heat pumps cost 50-75% less to operate than electric resistance heating. They struggle below -10°C without backup heat, but that's only 10-20 days/year in most of Ontario.
Why does my AC freeze up?
Ice on the evaporator coil has 4 causes: (1) dirty filter (restricted airflow), (2) low refrigerant (leak in coil), (3) dirty coil (blocked airflow), or (4) running AC below 15°C outdoor temp (refrigerant can't evaporate). Turn off AC, let ice melt, change filter, clean coil. If ice returns, call HVAC tech — low refrigerant means a leak, topping off is temporary. Replace the coil or system.
What's the difference between HRV and ERV?
HRV (Heat Recovery Ventilator) exchanges heat between outgoing stale air and incoming fresh air — recovers 60-80% of heat. ERV (Energy Recovery Ventilator) exchanges heat and moisture — recovers 50-70% of heat and prevents winter air from drying out. Use HRV in dry climates, ERV in humid climates or tight homes (Passive House). Both reduce heating/cooling costs by 20-30% vs opening windows.
Can I install a smart thermostat myself?
Yes, if you have a C-wire (common wire, 24V power). Most thermostats need 5 wires: R (power), G (fan), Y (cooling), W (heating), C (common). Older homes often lack C-wire — Ecobee includes adapter, Nest steals power from other wires (sometimes causes issues). Turn off furnace breaker, label old wires, connect new thermostat, test. If unsure, hire HVAC tech ($100-$200).
Why is one room always hot/cold?
Hot/cold spots have 5 causes: (1) undersized duct to that room, (2) duct leaks before that room, (3) closed/blocked register, (4) missing return air (door undercut needed), or (5) poor insulation in that room. Fix: balance dampers at trunk line, seal duct leaks, add return vent or undercut door 1", upgrade insulation. Manual D duct sizing prevents this during install.
How often should I change my furnace filter?
Depends on filter type. 1" fiberglass (MERV 4-6): monthly. 1" pleated (MERV 8-11): every 1-3 months. 4" pleated (MERV 11-13): every 3-6 months. HEPA filters (MERV 16+): every 6-12 months. Dirty filter is #1 cause of HVAC failures — restricted airflow overheats heat exchanger (furnace) or freezes coil (AC). Set phone reminder, check monthly, replace when dirty.
What is SEER2 and how does it differ from SEER?
SEER2 is the new 2023 efficiency standard for air conditioners and heat pumps — testing reflects real-world conditions better than old SEER standard. SEER2 ratings are 4-5% lower than SEER (e.g., SEER 16 = SEER2 15.2). Minimum SEER2 is 13.4 (was SEER 14). When comparing equipment, use SEER2 for apples-to-apples comparison — manufacturers list both during transition.
Why does my furnace have a yellow flame instead of blue?
Yellow flame = incomplete combustion (not enough air). Causes: dirty burners, clogged air intake, wrong gas pressure, cracked heat exchanger. Produces carbon monoxide (CO), soot, and wasted energy. Blue flame = complete combustion (proper air/fuel mix). Turn off furnace, call HVAC tech immediately — yellow flame is a CO poisoning risk. Install CO detectors on every floor while waiting for repair.
Is forced-air heating bad for indoor air quality compared to radiant?
Forced-air systems move air at high velocity through ducts, stirring up settled dust and recirculating it through living spaces. The heat exchanger "fries" dust particles (pyrolysis), creating ultrafine particulates and odours. Duct leaks — and most systems leak 20-30% of airflow — pull in unconditioned air from attics, crawl spaces, and wall cavities containing dust, insulation fibers, and biological contaminants. Forced-air also depletes negative ions in indoor air, which some research links to fatigue and respiratory discomfort. Hydronic radiant heating (in-floor or baseboard hot water) heats surfaces by radiation without moving air — no dust circulation, no duct leaks, no blower noise, and comfortable at 2-3°F lower thermostat settings. If radiant isn't an option, MERV 11+ filtration, sealed ductwork (under 3% leakage tested with duct blaster), and regular duct cleaning reduce forced-air health impacts significantly.
What MERV rating do I actually need for healthy indoor air?
MERV (Minimum Efficiency Reporting Value) rates filter effectiveness by particle size. MERV 1-4 (cheap fiberglass): removes less than 20% of particles — barely better than nothing. MERV 8 (standard pleated): removes over 70% of particles 3-10 microns (mold spores, dust mite debris). MERV 11 (higher-grade pleated): removes 65-80% of particles 1-3 microns (Legionella, auto exhaust, lead dust). MERV 13+: removes 90%+ of fine particles but restricts airflow — your blower must be sized for it or you'll burn out the motor. For most homes, MERV 11 in a 4-inch filter slot is the sweet spot — effective filtration without choking airflow. Important: MERV filters only capture particulates, not gases. Formaldehyde, VOCs, and other gaseous pollutants pass straight through. For gas-phase filtration, you need activated carbon or activated alumina media — available as standalone units or add-on modules for forced-air systems.
Where should the thermostat be placed for accurate readings?
Thermostat placement determines whether your HVAC cycles correctly or wastes energy fighting a false reading. Never within 6 feet of a supply register — direct airflow gives a false reading and the system short-cycles. Never on an exterior wall (cold in winter biases the reading). Never facing a window with direct sun (solar gain makes the space read warm). Never near a fireplace or kitchen (radiant heat skews the reading). Best location: interior hallway wall at 5 feet height, central to the living area, away from direct air sources. In a two-storey house with single-zone HVAC, the thermostat on the main floor means the upstairs is always 2-4°F warmer (heat rises). A zoned system with dampers and separate thermostats per floor solves this — worth the $2,000-$4,000 investment for homes over 2,500 square feet.
Why do my ducts make popping and rattling noises?
Sheet metal ductwork expands when heated and contracts when cooled — the popping or oil-canning sound is the metal flexing as temperature changes. Worst during startup (cold metal hit with warm air) and shutdown (hot metal cooling). Causes: undersized duct (air velocity too high, creates vibration), duct walls too thin (26-gauge minimum for trunks, 28-gauge for branches), long straight runs without stiffening (cross-breaks or standing seams every 4 feet), and loose connections at joints. For persistent noise in exposed basement ductwork, a thin coat of duct insulation (fiberglass liner or external wrap) dampens expansion noise and reduces heat loss through the duct walls. Flex duct (insulated flexible duct) is naturally quiet but restricts airflow more than metal — use it only for short final connections to registers, not for trunk lines.

Where we do this work

Based in Toronto, working across the GTA

TorontoMississaugaBramptonVaughanMarkhamRichmond HillAuroraOakvilleBurlingtonMiltonAjaxPickeringOshawaWhitbyHamilton

Ready to start your hvac project?

One crew, one fixed plan, and the live app on every hvac project. Daily photos, inspection reports, milestone pricing you approve — and a written warranty.

Get a Price EstimateBook your walkthrough
Fixed Milestone Pricing
Licensed & Insured
10% Holdback