A central air conditioner distributes cooled air throughout your home through a network of ducts connected to your existing furnace and its blower. If your home already has a forced-air furnace with ductwork in reasonably good condition, a central AC is the most natural and cost-effective cooling solution available — it uses the infrastructure that is already in place.

A central AC is the right choice when:

• Your home has a forced-air furnace with ducts reaching all living areas
• You want uniform whole-home cooling delivered invisibly through existing vents
• You are replacing an aging central AC unit while your furnace still has serviceable life remaining
• You prefer a completely concealed system with no visible equipment in living spaces
• You want the most widely available, most thoroughly serviced cooling technology in the Ontario market

If your home has no existing ductwork — older homes, historic properties, additions, or cottages — a ductless mini-split system is likely more practical. If your furnace is also aging and approaching end of life, a ducted heat pump that replaces both systems at once and qualifies for government rebates may be the smarter overall investment. Constant Home Comfort will help you evaluate all options at no cost during a free in-home consultation.

The duct system is not a passive part of your central AC installation — it is an active determinant of how well your new system will perform. A high-quality air conditioner installed on a poorly maintained duct system will consistently underperform its rated capacity and efficiency. Before purchasing, it's worth understanding your ductwork's condition.

Duct leakage: Most older Ontario homes lose 20 to 30% of conditioned air through gaps, failed duct tape, and poor connections before it reaches the living spaces. A central AC cooling effectively at the evaporator coil may deliver significantly less cooling at the registers if significant duct leakage exists. Sealing major duct leaks is one of the highest-return efficiency improvements available and is worth addressing alongside a new AC installation.

Duct sizing: Ducts that are undersized for the system's airflow requirements create high static pressure, reduce airflow, cause the evaporator coil to ice, and prevent the system from delivering its rated capacity. If your home has always had rooms that are much harder to cool than others, or if your current AC seemed weak even when it was new, duct sizing may be a contributing factor.

Return air capacity: An adequate return air pathway — through properly sized return ducts and grilles throughout the home — is essential for the system to pull enough warm indoor air across the evaporator coil. Insufficient return air is among the most common ductwork shortcomings in older Ontario homes and one that is frequently overlooked.

Duct insulation: Ducts running through unconditioned spaces — attics, crawlspaces, unheated garages — should be properly insulated to prevent energy losses before conditioned air reaches the living areas.

Constant Home Comfort assesses your ductwork as part of every central AC consultation. If we identify issues, we'll be specific about what is affecting performance, what remediation would cost, and how much improvement you can realistically expect — so you can make an informed decision.

Sizing is the single most critical technical decision in a central air conditioner purchase, and it is the decision most frequently made incorrectly by contractors who take shortcuts. Getting the size wrong — in either direction — creates problems that will affect your comfort and energy costs for the life of the system.

The Consequences of an Oversized System

An oversized air conditioner cools your home too quickly, satisfying the thermostat before completing a full cooling cycle. This short cycling means the system never runs long enough to adequately dehumidify the air. The result is a home that may feel cool in terms of temperature but remains muggy and uncomfortable — and it's a problem that no setting on the thermostat can fix. An oversized system also starts and stops more frequently, increasing wear on the compressor and shortening the system's useful life.

The Consequences of an Undersized System

An undersized system runs continuously during hot weather without reaching the thermostat set point. The home never cools adequately on the hottest Ontario days, the system operates at maximum capacity all the time rather than modulating, and electricity consumption is higher than it would be with a correctly sized system that can actually accomplish the job.

How Correct Sizing Is Determined

Proper sizing requires a Manual J heat load calculation — a formal engineering assessment that accounts for your home's specific characteristics rather than generic rules of thumb. A thorough Manual J calculation considers:

• Total conditioned floor area and ceiling heights throughout the home
• Wall, ceiling, floor, and attic insulation levels and construction type
• Window area, orientation, glazing type, and shading from overhangs or trees
• Home airtightness and air infiltration rate
• Local climate design conditions — including Ontario design temperatures for your specific municipality
• Internal heat gains from occupants, lighting, appliances, and electronics
• Duct system characteristics and distribution efficiency
• Any areas of the home that are unconditioned or thermally isolated

At Constant Home Comfort, every central air conditioner installation begins with a proper Manual J calculation. We never size a system based on the old unit's tonnage, square footage alone, or a contractor's rule of thumb. If a contractor gives you a firm size recommendation without conducting this assessment, that is a significant warning sign.

Once you know the correct size for your home, the next decision is the efficiency tier. Central air conditioners are rated by SEER2 — Seasonal Energy Efficiency Ratio 2 — which measures how much cooling a system delivers per unit of electricity consumed across an entire season. A higher SEER2 means lower electricity consumption for the same cooling output.

Here is a practical breakdown of what each efficiency level delivers and what it costs:

Standard Efficiency — SEER2 13.4 to 15

The current minimum for new residential systems in Canada. Single-stage compressors, straightforward reliable operation, and the lowest upfront cost. A reasonable choice for homeowners on a tight budget, those planning to sell within a few years, or rental properties where long-term operating cost optimization is not the primary goal. Performance is adequate — but comfort consistency and humidity control are noticeably behind what higher tiers offer.

Mid to High Efficiency — SEER2 16 to 18

A meaningful step up in both comfort and efficiency. Systems in this range typically use two-stage or entry-level variable-speed compressors that run longer at lower capacity on mild days, providing better humidity removal and more stable temperatures throughout the home. The price premium over base models is modest and is typically recovered through energy savings within three to five cooling seasons. This is the sweet spot for the majority of Ontario homeowners — meaningful efficiency gains at a justifiable price premium.

Premium Efficiency — SEER2 19 to 22+

The best available in residential central cooling. Variable-speed compressors that modulate continuously between roughly 25% and 100% of capacity, matching the home's exact cooling demand at every moment. The result is the most stable temperatures, the most effective humidity control, the quietest operation, and the lowest energy consumption of any compressor type. The higher upfront cost is the best long-term financial decision for homeowners planning to stay in their home for 10 or more years — and for anyone who prioritizes comfort and humidity control as primary criteria.

Important note on SEER2 vs. legacy SEER: as of January 2023, efficiency ratings in Canada moved to the SEER2 standard, which uses test conditions that more accurately reflect real-world installed performance. A SEER2 of 13.4 is roughly equivalent to a legacy SEER of 14. When reading older documentation or comparing quotes, confirm which standard is being referenced.

The compressor is the heart of your central air conditioner, and the type of compressor determines more about your day-to-day comfort experience than any other single component. Understanding the differences helps you evaluate what you're actually getting at each price point.

Single-Stage Compressors

Operates at one speed: full capacity. On or off. When cooling is called for, the system runs at 100% until the thermostat is satisfied, then shuts off completely. This results in more noticeable temperature swings, shorter run times that limit humidity removal, and higher operating noise during cycles. Single-stage compressors are reliable and straightforward — the technology has been in use for decades — but they represent the lowest tier of comfort performance.

Two-Stage Compressors

Can operate at two distinct capacity levels, typically around 65% and 100%. On mild summer days — which make up a significant portion of the Ontario cooling season — the system runs at the lower stage for longer, providing better humidity control, more consistent temperatures, and improved efficiency. It steps up to full capacity on the hottest days when maximum output is needed. A two-stage system represents a meaningful upgrade in real-world comfort over a single-stage unit with a moderate upfront premium.

Variable-Speed (Inverter) Compressors

The most advanced compressor technology available in residential central AC. A variable-speed compressor adjusts its output continuously across a wide range — from as low as 25% to 100% of rated capacity — matching the home's exact cooling demand at any given moment. In practice, this means the system runs almost continuously during warm weather at a low, quiet, efficient speed, modulating gently as conditions change rather than switching abruptly on and off. The specific advantages are substantial and worth understanding:

• Temperature consistency: Temperature variation throughout the home is minimized. A variable-speed system maintains set temperature within a fraction of a degree rather than the broader swing characteristic of single-stage systems.
• Humidity control: Long, low-speed run cycles are the most effective way to remove moisture from indoor air. Variable-speed systems consistently deliver the best dehumidification performance of any compressor type — a significant comfort factor in Ontario's humid summer climate.
• Energy efficiency: Running at low speed most of the time consumes far less electricity than cycling on and off at full capacity. Variable-speed systems achieve the highest SEER2 ratings available and deliver measurably lower electricity bills over a full cooling season.
• Operating noise: At low speed, a variable-speed compressor is often barely perceptible indoors. Homeowners who switch from a single-stage to a variable-speed system frequently comment that the new system is almost silent by comparison.
• Component longevity: Smooth, continuous operation at variable speeds places far less mechanical stress on the compressor than the repeated hard starts and stops of a single-stage unit. This contributes to longer compressor life and fewer mechanical failures over time.

Every brand Constant Home Comfort carries is selected because we believe in it — not simply because it's available or affordable. That said, different brands occupy different positions in the market and suit different buyer priorities. Here is an honest assessment:

Lennox

Lennox is the benchmark for premium residential central air conditioning in North America. Their top-tier XC25 and XC21 systems achieve SEER2 ratings of 22 or higher through variable-speed compressor technology, their proprietary Precise Comfort modulating system, and advanced humidity sensing. Lennox units are among the quietest residential AC systems on the market, integrate seamlessly with the iComfort smart thermostat platform, and are built to a quality standard that supports 20-plus years of reliable service. The Lennox warranty — up to 10 years on registered equipment — reflects the manufacturer's confidence in their own product. Lennox is the unambiguous choice for homeowners who want the best performance available and will be in their home long enough to fully realize the energy savings and comfort advantages.

Daikin

Daikin's position as the world's largest air conditioning manufacturer is the product of genuine technical leadership — including the invention of many of the inverter and variable-speed compressor technologies now used across the industry. Their residential central split system lineup brings that expertise to Canadian homes with ENERGY STAR certified models, strong variable-speed options, excellent humidity management, and the reliability that comes from Daikin's global manufacturing scale and quality standards. Daikin systems consistently deliver Lennox-tier performance at a somewhat more accessible price point, making them outstanding value in the premium-to-mid-premium segment. Their warranty and service network in Ontario are both strong.

American Standard

American Standard is one of the most recognized names in North American home comfort, with a track record stretching back more than a century. Their central air conditioner lineup spans from reliable entry-level single-stage models through premium variable-speed systems, all built to consistent quality standards and backed by comprehensive warranty coverage. American Standard is a strong choice for homeowners who want proven technology from a brand with a long history of standing behind their products — at a price point that offers competitive value across all efficiency tiers. Their two-stage and variable-speed models are particularly well regarded for their reliability and comfort performance in Ontario's climate.

Bosch

Bosch brings the engineering precision of one of the world's most respected industrial manufacturers to residential central air conditioning. Their systems are characterized by quiet, efficient operation, high efficiency ratings, and the build quality consistency that defines Bosch products across all categories. Bosch is a particularly strong choice for homeowners who prioritize engineering quality and understated reliability over brand recognition, and who want a system that will operate quietly and dependably for many years without drawing attention to itself. Their central AC lineup offers competitive SEER2 ratings and a strong value proposition in the mid-to-high efficiency tier.

If your furnace is also aging — 10 years old or more, or showing signs of wear — this is the most important step to take seriously before committing to a conventional central AC replacement.

A ducted heat pump uses the same refrigeration technology as a central air conditioner and performs identically in cooling mode. The difference is that a heat pump adds a reversing valve that allows the system to extract heat from outdoor air and deliver it inside during winter — replacing or supplementing your gas furnace. If your furnace is due for replacement within the next few years, replacing both systems at once with a heat pump avoids the cost of two separate installation visits, two sets of equipment, and two rounds of disruption to your home.

The financial case for a heat pump becomes even more compelling when Ontario rebates are factored in. Qualifying ducted heat pump installations currently receive grants through the Canada Greener Homes program of up to $5,000, plus Enbridge Home Efficiency Rebate Plus for eligible gas customers. Standalone central AC replacements receive no government rebates. After rebates, the net installed cost of a high-efficiency heat pump is frequently competitive with a conventional central AC installation — and the heat pump handles both heating and cooling.

We are not suggesting that every homeowner should choose a heat pump over a central AC. If your furnace is new or mid-life, replacing just the AC makes perfect sense. But if your furnace is aging, the heat pump path is worth evaluating thoroughly before deciding. Constant Home Comfort will walk you through a complete side-by-side comparison during your free consultation.

A central air conditioner performs only as well as its installation. A technically superior piece of equipment installed incorrectly — wrong refrigerant charge, poor electrical connections, inadequate duct assessment, sloppy coil installation — will underperform, fail prematurely, and void your manufacturer warranty. Here is what a complete, professional installation from Constant Home Comfort includes:

• In-home assessment and Manual J sizing calculation: Confirms the correct system size, identifies any ductwork issues, and establishes the full system design before any equipment is ordered.
• Removal and responsible disposal of old equipment: Your existing outdoor condenser and indoor evaporator coil are removed, old refrigerant is properly recovered by a licensed technician, and all components are disposed of responsibly.
• Outdoor condenser installation: Mounted on a level concrete pad or equipment bracket, positioned for optimal airflow, code-compliant clearances, and minimal noise impact. Refrigerant lines are properly connected, insulated, and weatherproofed.
• Indoor evaporator coil installation: Installed on or beside the furnace air handler in the correct orientation and sealed to prevent air bypass. Condensate drain connected and tested.
• Electrical connection by a licensed electrician: Dedicated circuit, disconnect box, and breaker sizing all completed to code. Panel upgrades included in the quote if required.
• System commissioning: Refrigerant charge verified against manufacturer specifications using gauges and superheat or subcooling measurements. Leak testing performed. Airflow measured at representative registers. System run through a full cooling cycle and confirmed operating correctly.
• Thermostat setup: Thermostat confirmed compatible with the new system, programmed to your preferences, and tested for correct operation. Smart thermostat installation included if selected.
• Homeowner walkthrough: We explain how to operate your system, set schedules, perform basic filter maintenance, and what signs to watch for between service visits.

A central air conditioner that is properly maintained will serve your home reliably for 15 to 20 years. The maintenance requirements are modest but genuinely matter — neglected systems develop problems that reduce efficiency, shorten lifespan, and eventually cause failures that proper care would have prevented.

Change the air filter regularly: This is the single most important homeowner maintenance task. A clogged filter restricts airflow, causes the evaporator coil to ice over, reduces cooling capacity, stresses the blower motor, and degrades indoor air quality. Check monthly during the cooling season and replace every one to three months depending on filter type and household conditions. Use the filter MERV rating recommended for your system.

Keep the outdoor condenser clear: Remove leaves, grass clippings, cottonwood, and debris from around the outdoor unit each season. Maintain at least 18 to 24 inches of clearance on all sides. Rinse the condenser coil with a gentle hose spray in spring to remove pollen and fine debris from the fin surface.

Keep indoor registers open and unobstructed: Closing registers in unused rooms does not save energy in a central system — it creates static pressure imbalances that reduce efficiency and can cause the evaporator coil to ice. Keep all supply and return registers open and free of furniture and obstructions.

Schedule annual professional maintenance: A yearly tune-up by a certified technician — including evaporator and condenser coil inspection and cleaning, refrigerant level check, electrical component inspection, condensate drain flush, airflow measurement, and full operational test — extends system life, maintains efficiency, and satisfies most manufacturer warranty requirements.

Monitor system behaviour: If your system starts running longer to reach temperature, makes a new sound, or produces less cooling than it used to, call for a service visit rather than waiting for a complete failure. Early diagnosis of developing issues is almost always less expensive than emergency repair.

Beyond routine maintenance, it's worth considering how you want to handle the repair costs that inevitably arise over a 15 to 20-year system lifespan. Constant Home Comfort offers two options that together provide comprehensive coverage:

Maintenance Plan: Annual professional tune-up visits, priority emergency dispatch, and discounted parts and repairs. Reduces the likelihood of breakdowns and satisfies manufacturer warranty requirements.

Protection Plan: Parts and labour coverage for major component failures — compressor, evaporator coil, blower motor, control board, and more. Converts unpredictable repair bills into a predictable annual cost and ensures 24/7 emergency service access.

Many homeowners enrol in both plans at the time of installation, establishing complete coverage from day one. Ask us about combined plan pricing when you request your installation quote.

• Accepting a size recommendation without a load calculation: The most consequential error. Any contractor who quotes a system size without performing a Manual J assessment is guessing — and you'll live with the consequences of that guess for 15 to 20 years.
• Choosing based on the lowest quote alone: A low equipment price combined with inadequate installation, excluded components, or missing electrical work is not a good deal. Always compare fully itemized, all-in quotes.
• Replacing only the outdoor unit without assessing the indoor coil: If the indoor evaporator coil is old, incompatible with the new system's refrigerant, or already developing a leak, replacing only the outdoor unit creates efficiency, warranty, and reliability problems that will surface within a few years.
• Not considering efficiency over the full lifespan: The upfront cost difference between a SEER2 14 and a SEER2 18 system is often recovered through energy savings within three to five years. Buying the cheapest system is frequently the most expensive long-term decision.
• Ignoring the heat pump alternative if the furnace is aging: A homeowner whose furnace is 12 years old who replaces only the AC will likely face a furnace replacement in three to five years — a second installation visit, a second set of equipment costs, and a second round of disruption. If the timing works, replacing both at once with a heat pump is worth evaluating carefully.
• Hiring an uncertified installer: Central AC installation requires licensed refrigeration mechanics and electricians in Ontario. Uncertified installation voids your manufacturer warranty, may create safety and code compliance issues, and often results in a system that never performs as designed.
• Not registering the system after installation: Most manufacturers require registration within 60 to 90 days of installation to activate extended warranty coverage. An unregistered system reverts to the base warranty, which is typically shorter and less comprehensive. Constant Home Comfort handles registration as part of every installation.

How do I know when my current AC needs to be replaced rather than repaired?

A useful general guideline is the 50% rule: if the cost of a repair exceeds 50% of the installed cost of a comparable new system, replacement is typically the better financial decision. Age is also a strong factor — a system 12 to 15 years old that requires a significant repair (compressor, evaporator coil) is unlikely to provide many more years of reliable service. If your system has had multiple repairs in recent years, is consistently failing to keep up on hot days, or has refrigerant that is no longer readily available (R-22), replacement is almost certainly the right path. Our technicians will give you an honest assessment.

Can I install a central AC without a furnace?

A central split system air conditioner requires an indoor air handler to circulate air through the ductwork. In most Ontario homes, the gas furnace serves as the air handler — the furnace blower pushes air across the evaporator coil and through the ducts even when no heat is being produced. If your home has electric heat rather than a gas furnace, a dedicated air handler can be used instead. Our technicians will assess your existing equipment and confirm the right configuration for your home.

What refrigerant does a new central air conditioner use?

New central air conditioners currently use R-410A refrigerant, which replaced the older R-22 (Freon) that was phased out due to its ozone-depleting properties. The industry is transitioning to R-454B in newer systems, which has a lower global warming potential than R-410A. If your existing system uses R-22, a full system replacement is required — R-22 is no longer manufactured in Canada and is costly to source for repairs. Our technicians will confirm the refrigerant type during the assessment.

How noisy is a central air conditioner?

The noise level of a central AC depends significantly on the compressor type and the quality of the installation. Single-stage systems are the loudest — particularly at startup — and can be noticeable from a normal distance outdoors. Two-stage and variable-speed systems are meaningfully quieter, especially when operating at lower capacity stages. Premium variable-speed systems from Lennox, Daikin, and others are engineered specifically for quiet operation and are often rated at 58 to 69 dB at the outdoor unit — comparable to a normal conversation at a few metres. Indoor noise from the air handler is primarily a function of duct design and blower speed.

What is the difference between SEER and SEER2?

SEER (Seasonal Energy Efficiency Ratio) was the efficiency rating standard for air conditioners until January 2023, when Canada adopted SEER2. SEER2 uses more realistic test conditions that better reflect actual installed performance — specifically, higher external static pressure in the duct system, which is the most significant difference. A SEER2 of 13.4 is roughly equivalent to a legacy SEER of 14. When comparing systems or reviewing older documentation, confirm which standard applies. All new systems sold in Canada are now rated in SEER2.

Does a central air conditioner also improve indoor air quality?

A central air conditioner contributes to indoor air quality in two ways: it removes humidity from indoor air, which reduces conditions that support mould growth and dust mite populations, and it circulates indoor air continuously through the air filter, which captures airborne particles including dust, pollen, and pet dander. The effectiveness of filtration depends on the MERV rating of the filter in use — a higher MERV filter captures finer particles but also restricts airflow more, so filter selection should be matched to what the system is designed to handle. For enhanced air quality, a whole-home air cleaner or UV system can be added to most central AC installations.

The most valuable thing you can do right now is schedule a free, no-obligation in-home consultation with a Constant Home Comfort certified technician. There is no substitute for a professional who has seen your home, assessed your ductwork, calculated the correct system size, and evaluated your existing equipment — before making any recommendation about what system you need.

We carry Ontario's best selection of central air conditioners from Lennox, Daikin, American Standard, and Bosch. We'll help you find the right system at the right price, explain every option honestly, and make sure your installation is done to the standard your investment deserves.

Call us: 1 (888) 675-5907

Visit: constanthomecomfort.com

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