Cassar Heating & Air Conditioning installs, repairs, replaces, and maintains gas furnaces across Durham Region, Ontario. TSSA-certified technicians. Same-day service available. Honest pricing every time.
Our Furnace Services
From brand-new installs to emergency repairs on the coldest night of the year — Cassar's TSSA-certified team handles every furnace job across Durham Region.
New builds and full replacements. Correct sizing, Ontario-code installation, gas line, venting, and electrical — all in one visit.
No heat, short-cycling, strange noises, error codes. We diagnose all makes and models — often same-day — with upfront pricing before we start.
When repair doesn't make sense, we walk you through your options honestly — no pressure. Old unit removal and disposal included.
Pre-season inspection, cleaning, safety check, and filter change. Book in September or October — before your furnace has to work hard.
Ontario winters don't take weekends off. Call us day or night — David and his crew respond quickly across all of Durham Region.
Upgrade to 96%+ AFUE and see it in your gas bill. We advise on available Ontario rebate programs and only recommend what suits your home.
The Process
No surprises, no confusion. Here's exactly what happens from your first call to a warm home.
Call (416) 508-4585 or book through the website. We'll confirm a same-day or next-day visit — no week-long waits.
We assess your furnace, explain exactly what we found, and give you a clear upfront price. No work starts until you say go.
Installation, repair, or maintenance completed to Ontario code. We protect your floors, tidy up fully, and test everything before leaving.
We walk you through what was done, answer any questions, and leave you with a fully working system and a clean work area.
Why Choose Cassar
Homeowners from Oshawa to Orono choose Cassar because we answer the phone, show up when we say we will, and leave the job site cleaner than we found it. No upselling, no inflated quotes, no surprises on the invoice.
Who We Are
Cassar Heating & Air Conditioning is a Durham Region-based HVAC company built on doing things properly. David Cassar is a TSSA-licensed gas technician who has been keeping homes in Oshawa, Whitby, Ajax, Pickering, and across Durham warm and comfortable for years.
Unlike the large franchises, when you call Cassar you speak directly with the person showing up at your door. David troubleshoots over the phone before dispatching, is transparent about what your system actually needs, and won't recommend a replacement when a repair is the right call.
The result is a company with a near-perfect review record, customers who refer their neighbours, and a reputation across Durham Region for being the HVAC company you call when you want it done right.
By the Numbers
What Customers Say
A small sample of what homeowners across Durham Region say about Cassar furnace service.
"Seriously I can't say enough — reliable, best pricing, honest and just a genuinely nice guy. We were in a pinch and he installed our new furnace in a snow storm! He left the furnace area cleaner than it was when he arrived."
"David and his crew fast-tracked my furnace and AC replacement just in time. Punctual, kept to his word, maintained open communication throughout. Will recommend Cassar Heating and Air to others."
"Dave isn't pushy and gives his honest opinion and options. They get the job done right the first time. Fast and efficient. If you use Cassar Heating & Air Conditioning you won't be disappointed."
Furnace Buying Guide
Straight answers to the questions we hear most — before you spend a dollar.
Furnace size is measured in BTUs (British Thermal Units) and has to match your home — not just your square footage. A proper sizing calculation factors in insulation quality, ceiling height, window area, and even which direction your home faces. Oversized furnaces are one of the most common installation mistakes: they short-cycle, wear out faster, and heat unevenly. Cassar performs a heat load calculation on every new installation. We never just match the old unit.
A well-maintained gas furnace in a Durham Region home typically lasts 15–20 years. Annual tune-ups, regular filter changes, and prompt repairs extend that lifespan significantly. If your furnace is under 12 years old, repair is almost always the right call. If it's over 18 years old and showing signs of trouble, replacement is usually the better investment.
The standard rule: if the repair cost exceeds 50% of the cost of a new unit, and the furnace is more than 10–12 years old, replacement usually makes more financial sense. A newer high-efficiency furnace will also reduce your gas bill, so the savings offset part of the upfront cost. David will give you an honest assessment — he won't push replacement when a repair is the right answer.
Most Durham Region furnace installations range from $2,800 to $5,500 all-in, depending on the unit's efficiency rating, brand, and installation complexity. High-efficiency two-stage units sit at the higher end of that range but deliver lower gas bills year over year. Cassar provides clear, itemised quotes before any work begins — no surprise charges on completion.
Yes — Ontario homeowners upgrading to high-efficiency equipment may be eligible for rebates through Enbridge Gas conservation programs and federal incentives. Eligibility depends on your current equipment, the unit you're installing, and your home's energy profile. Ask at your Cassar consultation and we'll walk you through what applies to your specific situation.
In Durham Region's dry winters, a whole-home humidifier paired with a new furnace makes a noticeable difference in comfort. Forced-air heating strips moisture from the air — low humidity makes 20°C feel colder, dries out wood floors and trim, and contributes to static, dry skin, and respiratory irritation. A bypass or flow-through humidifier installed at the same time as your furnace is the most cost-effective way to add one.
AFUE (Annual Fuel Utilization Efficiency) measures how much of your gas dollar becomes heat. An 80% AFUE furnace wastes $0.20 of every dollar. A 96%+ AFUE unit wastes less than $0.04. In Durham Region's climate — where furnaces run hard from October through April — that gap adds up to real money every year. For most homes, the extra upfront cost of a high-efficiency unit is recovered within 3–5 years through gas savings alone.
Still not sure? Call David directly at (416) 508-4585 — he'll talk through your situation honestly before recommending anything.
Year-Round Care
Durham Region's climate puts real demands on home heating systems. Here's what to pay attention to — and when.
The best time to book a furnace tune-up is before the season starts. A pre-season inspection catches issues while parts are available, ensures your heat exchanger is crack-free, and confirms your system is operating safely and efficiently. Don't wait for the first cold night to find out something is wrong.
Short-cycling, unusual noises, uneven room temperatures, higher-than-normal gas bills, or a yellow pilot flame are all signs your furnace needs attention. In a Durham Region winter, don't ignore them — small issues become emergencies fast. Call early and you'll almost always avoid an after-hours service call.
If your furnace made it through winter but showed signs of wear, spring is the ideal time to replace it. Installers are less busy, equipment lead times are shorter, and you'll have months before you actually need reliable heat again. Replacing in spring almost always means better pricing and scheduling flexibility.
Even when your furnace isn't running, it needs attention. Replace your air filter every 1–3 months year-round. Check that intake and exhaust vents are clear of nests, debris, or overgrowth. Test your thermostat before you need heat. These simple steps prevent most service calls before they happen.
Common Questions
Quick answers to the questions we hear most from Durham Region homeowners.
Looking for more detailed answers specific to your area? See the full Durham Region furnace guide →
Find Your Area
We provide furnace installation, repair, and maintenance across all of Durham Region. Select your community for locally-specific information, pricing context, and service details.
Related Services
Cassar handles all your home comfort needs — not just furnaces. Explore our other services across Durham Region.
Same-day service available across all of Durham Region.
TSSA certified. Honest pricing. No surprises.
