Gas furnace
Lennox ML296V
96% AFUE, two-stage, variable-speed blower, 45,000 to 110,000 BTU
20-year limited heat exchanger warranty
Thornhill · Vaughan and Markham
Thornhill HVAC Contractor for Furnace, AC and Airflow Upgrades
A new furnace won't help much if the ducts are the real problem
Thornhill straddles Vaughan and Markham, and a lot of its HVAC is now 40 to 50 years into the life of the house. We replace aging furnaces and air conditioners, clean up leaky and undersized ductwork, and fix the airflow problems that leave some rooms stuffy and others drafty. You get a guaranteed written price before we start.
- Static pressure and airflow testing on every replacement quote
- Duct sealing, added returns and repaired runs
- Two-stage furnaces with a matched AC or heat pump
- After-hours help on weekends and holidays
Voted Best Company 2019 to 2021 · Authorized Midea, Lennox, Kepler & Rinnai dealer, plus Goodman · 20+ years
Our Brand Partners
Heating and cooling in Thornhill: the house matters most
Thornhill homes share a few traits that decide what a good replacement looks like.
- Typical homes1970s and 1980s family houses
Royal Orchard, Bayview Glen and Spring Farm are full of homes from that era. Thornhill Woods is newer and larger, and Old Thornhill has heritage houses.
- Two citiesSplit by Yonge Street
West of Yonge is Vaughan and east is Markham. Our Vaughan HVAC and Markham HVAC pages cover those wider cities. Permits go through yours, and we look after them.
- UtilitiesAlectra Utilities and Enbridge Gas
Both sides of Yonge share the same hydro and gas providers, so running cost comparisons work the same anywhere in Thornhill.
- DuctworkOriginal and often tired
After four or five decades, joints loosen, old tape dries out and many homes never had enough returns. So we look at the ducts before we size new equipment.
Airflow problems in 40-year-old Thornhill homes, and the fixes
When the furnace gets replaced but the ducts don't, these complaints tend to stick around.
Some registers barely push any air
Old duct joints separate over time, and air leaks into the basement ceiling instead of reaching the room. We find the leaks, seal them with mastic or foil tape, and reconnect or replace crushed runs.
The new furnace is louder than the old one ever was
A modern blower pushing through small or restricted ducts creates high static pressure, and you hear it as whistling or rushing air. We measure it, then add return capacity or open the restriction so the blower can run at a quieter speed.
Dust is back on the shelves a day after you wipe them
Leaky return ducts pull dusty air from the basement and wall cavities. Sealing the returns and fitting a proper media filter cabinet keeps that dust out of the living space.
Two floors share one big return grille
Homes of this age were often built with very few returns, so bedrooms with the door closed starve for air. Adding returns or transfer grilles lets air get back to the furnace and evens out the rooms.
The AC coil ices over on hot afternoons
Low airflow across the coil is a common cause, along with a clogged filter or low refrigerant. Our licensed refrigeration techs check all three before recommending a repair or a new matched system.
Repairs on the 1990s furnace keep piling up
Ignitors, inducer motors and control boards tend to fail in clusters at that age. Our TSSA-certified gas techs check the heat exchanger and repair history, then tell you plainly whether a repair still makes sense.
The basement is toasty while the second floor waits for heat
In many Royal Orchard and Brownridge two-storeys, the trunk feeds the basement registers first and the upstairs runs get what's left. Partly closing the basement dampers, adding a return upstairs and setting the blower to a steadier low speed shifts warm air to the bedrooms without touching the walls.
Sound familiar?
Describe the problem and we'll tell you what it usually is, what it costs to fix, and whether it's worth fixing.
Thornhill furnace, AC and duct repair prices
Duct work gets its own line on a Thornhill quote, so you can see what the equipment costs and what the airflow fixes cost before you decide on either.
| Service | Typical price in Thornhill |
|---|---|
| Furnace repair Diagnostic visit plus common parts such as ignitors, flame sensors and capacitors | Quote after diagnosis |
| AC repair Diagnostic visit plus common parts such as capacitors, contactors and refrigerant leak repair | Quote after diagnosis |
| High-efficiency furnace, installed Lennox ML296V or Midea MGH96, 96% to 97% AFUE, two-stage variable-speed | From $3,300 |
| Central air conditioner, installed Lennox or Midea, sized from a heat-gain calculation | Written quote |
| Cold-climate heat pump, installed Midea EVOX G3 or Kepler, 2 to 5 ton, rated to -30°C | From $5,500 |
Installed pricing depends on size and installation requirements, and every job gets a written, guaranteed quote. Qualifying cold-climate heat pumps can bring back up to $7,500 through the Home Renovation Savings Program, and financing runs 0% for 3, 6 or 9 months on approved credit.
Furnaces, coils and duct work from recent jobs
Photos from recent Ontario installs, including sealed plenums and new return drops. The same approach goes into a Thornhill basement.
HVAC services in Thornhill on both sides of Yonge
Pick the service that matches your problem. Each page goes into the equipment, the options and the process.
Furnace repair in ThornhillIgnition faults, inducer noise and short cycling on aging furnaces.Furnace and AC replacement in ThornhillMatched equipment sized from a load calculation, with the ducts checked first.AC repair in ThornhillFrozen coils, weak airflow and condensers that trip the breaker.Tune-ups and airflow checksYearly maintenance that covers the filter, the blower and a static pressure reading.Hybrid heat pump systemsA cold-climate heat pump paired with your new furnace to cut gas use.Whole-home humidifiersRelief from dry winter air, static shocks and gaps in hardwood floors.Emergency HVAC in ThornhillEvenings, weekends and holidays when the heat or cooling quits.Heat pump rebatesGas-heated homes may qualify for a smaller rebate. We file the paperwork.
How a Thornhill HVAC technician scopes your replacement
We look at the ducts and the equipment together, then give you one price.
- 1
Tell us what's bugging you
Noisy vents, hot bedrooms, dust, high bills. Call or use the form and give us the details.
- 2
Test the whole system
We measure static pressure, check airflow at every register and look for leaks at the trunk and joints.
- 3
Get a quote with duct work listed
Equipment, model numbers and any duct repairs appear as separate lines, so you can see exactly what you're paying for.
- 4
Install, seal and balance
We install the new equipment, seal and fix the ducts, balance the airflow and register your warranty.
Furnaces and heat pumps we fit into Thornhill basements
Two-stage, variable-speed furnaces are the natural match for older ducts, because the blower can run slow and quiet most of the time. Each model below is one we install and register ourselves.
Gas furnace
Lennox EL297V
97% AFUE, two-stage, variable-speed blower
20-year limited heat exchanger warranty
Gas furnace
Midea MGH96
96.5% AFUE, two-stage, variable-speed, 60,000 to 120,000 BTU
Registered warranty, up to 12 years parts and labour on select systems
Gas furnace
Goodman GMVC96
Up to 96% AFUE, two-stage, variable-speed ECM blower, 40,000 to 120,000 BTU/h input
10-year parts and unit replacement limited warranties when registered online
Cold-climate ducted heat pump
Midea EVOX G3
2 to 5 ton, inverter, R-454B, ENERGY STAR cold climate, rated to -30°C
Up to 12 years parts and labour on select systems
Ducted heat pump
Kepler cold-climate
1.5 to 5 ton, rated to -30°C, quiet operation
Registered warranty
Single and multi-zone
Midea ductless
18,000 to 60,000 BTU outdoor units, wall-mounted heads
Registered warranty
Why a static pressure test comes before any Thornhill furnace quote
Static pressure is the resistance the blower pushes against to move air through your ducts. We measure it with a manometer at the furnace, on the supply side and the return side, before we size anything.
In a 1970s or 1980s Thornhill house the reading is often well above what the new furnace is built for. That tells us the ducts, not the furnace, are the bottleneck. A bigger furnace would make it worse. The right answer is usually a second return, a larger filter cabinet or a short section of trunk opened up, and then a furnace sized to the house's real heat loss.
The test takes a few minutes and the numbers go on your quote, so you can compare them to the readings we take again after the duct work is done.
What it costs, and how we keep it lower
Guaranteed pricing
Your quote is your final price. No surprise extras on the agreed scope of work.
Rebates up to $7,500
Cold-climate heat pumps may qualify through the Home Renovation Savings Program. We confirm eligibility and file the paperwork.
0% financing
Interest-free for 3, 6 or 9 months, or open loans from 2.99% on approved credit.
Up to 12 years parts and labour
Extended warranty on select systems when registered.
Want the real number for your home?
A guaranteed quote takes one visit. Rebate and financing options come with it.
Thornhill neighbourhoods from Royal Orchard to Thornlea
We cover Thornhill from the Vaughan side to the Markham side, including:
- Old Thornhill
- Thornhill Woods
- Royal Orchard
- Uplands
- Bayview Glen
- Brownridge
- Spring Farm
- Pomona Mills
- Thornlea
What Thornhill homeowners can expect: our customers in their own words
Rated 4.5 on Google and voted Best Company 2019, 2020 and 2021 on HomeStars.
4.5Google rating from verified customers
We had a heat pump/AC unit installed by EHI, on time, on budget, great workmanship. Julian and team were knowledgeable and courteous. Dustin communicated well and is managing our government rebate for the new efficient system. Thank you Team!
Replaces our AC with a new heat pump in Ottawa and the whole experience was outstanding. From the first call, Dustin was incredibly responsive and communicated clearly every step of the way. He cut through all the usual sales fluff and got straight to what mattered — options, costs, timelines, and what made the most sense for our home. They addressed every concern I had, explained the details discussed my technical questions, and handled the installation quickly and professionally. The quality of the work is excellent, everything was done cleanly, and the system has been running perfectly since. Pricing was fair and transparent, and there were no surprises. It’s rare to find a company that combines speed, honesty, and solid workmanship like this. Highly recommended.
Recently got a shiny new heat pump installed. Went very well, nice unit and it works soooo quietly. These fine folks were very easy to deal with, professional and thourough. Would highly recommend.
Efficient Home Improvements truly went above and beyond. Our furnace failed on Christmas Eve in Ottawa, and their team stayed up late (3:00am) that night to replace it. Their responsiveness, professionalism, and dedication during the holidays were exceptional. The work was completed efficiently, and everything was explained clearly. It’s rare to find a company willing to sacrifice their own holiday time to ensure a customer’s home is warm and safe. I highly recommend Efficient Home improvements to anyone in need of reliable and compassionate service.
I recently had a new furnace and tankless water heater installed by this company. Excellent service by both office and technicians , I highly recommend!
The Installers were great.. Got in and got the job done..the furnace works amazing compared to the old one !!! Need a furnace..A/C water tankless system..there your guys!!!!
Had a tankless water heater installed and couldn’t be happier. The installation was quick, professional, and the system works great — endless hot water and more efficient than my old tank. Highly recommend!
Dustin and his team were really responsive and helpful in getting us a new heat pump to replace our broken AC unit. The team went above and beyond helping us through the process and answering other questions about the house we recently moved in to. I would highly recommend Efficient Home Improvements for any of your HVAC needs.
Licensed HVAC Contractor · Serving Ontario for 20+ Years
Proudly Serving Thornhill, Ontario
EHI Heating And Cooling has kept Ontario homes and businesses comfortable for more than 20 years. Our licensed crews come to your home or business anywhere in Thornhill, with a written, guaranteed quote before any work starts.
- ServingThornhill, Ontario
- Phone1-647-694-5845
- Emailefficienthomecomfort@gmail.com
Business Hours
- Monday8:00 AM to 8:00 PM
- Tuesday8:00 AM to 8:00 PM
- Wednesday8:00 AM to 8:00 PM
- Thursday8:00 AM to 8:00 PM
- Friday8:00 AM to 8:00 PM
- Saturday8:00 AM to 8:00 PM
- Sunday10:00 AM to 5:00 PM
Emergency service available evenings, weekends and holidays.
We also serve communities near Thornhill
Other cities in Toronto and York Region we serve
Every city gets the same licensed crews, guaranteed pricing and rebate paperwork. Pick yours for local details.
- TorontoHVAC services
- ScarboroughHVAC services
- North YorkHVAC services
- EtobicokeHVAC services
- MarkhamHVAC services
- Richmond HillHVAC services
- VaughanHVAC services
- WoodbridgeHVAC services
- AuroraHVAC services
- NewmarketHVAC services
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Frequently asked questions
Is Thornhill part of Vaughan or Markham?
Both. Thornhill west of Yonge Street is in Vaughan and the east side is in Markham, and we serve the whole community either way.
Should I fix my ducts before replacing my furnace?
Yes, if the ducts are leaky, crushed or short on returns. A new furnace on bad ducts runs louder and still leaves rooms uneven, so we fix both in the same job.
How do I know if my Thornhill home has a duct problem?
Uneven rooms, weak airflow at some registers, whistling vents and extra dust are the usual signs. A static pressure test confirms it.
What will furnace installation in Thornhill cost with duct repairs?
A high-efficiency furnace in Thornhill starts from $3,300 installed. Installed pricing depends on size and installation requirements, plus any duct repairs, and the quote is guaranteed in writing.
Can a Thornhill HVAC contractor work on a heritage home in Old Thornhill?
Yes. In older houses with little room for ducts we often use ductless or multi-zone heat pumps, which need only small wall openings.
Is there emergency HVAC in Thornhill on both sides of Yonge?
Yes. Our technicians answer after-hours emergency calls on the Vaughan and Markham sides alike, including weekends and holidays. Call 1-647-694-5845.
Page reviewed and updated October 27, 2026. Prices, rebates and program terms are checked at each update.