Heating and Air Conditioning

AC Season Will Be Here Soon!

Get Maintenance And Repair

Deep-Cleaning Air Conditioning

Professional Service For Your A/C Unit

Unionville Heating recommends this preventative maintenance service if your A/C unit hasn’t been cleaned in the past 3 to 5 years.

Order your professional deep-cleaning A/C service before April 30 and receive 25% off a furnace filter.

Call us or complete the online form here.

before and after A/C coil deep-cleaning

Order Deep-Cleaning A/C Service

Unionville Heating provides an exclusive service for deep-cleansing of your outdoor AC unit.

Please Cast Your Vote

We are once again looking for your help with a nomination in the category of “Best HVAC Services” in Stouffville and Markham/Unionville.  Please click a button link below to vote for Unionville Heating & Air Conditioning.  Thank you for your vote!

Voting Open for 2022 Best HVAC Contractor Stouffville

Please cast your vote on YorkRegion.com's website. Home/Home Improvement Category

Voting Open for 2022 Best HVAC Contractor Markham/Unionville

Please cast your vote on YorkRegion.com's website. Home/Home Improvement Category
Reader's Choice 2022 Markham Diamond Award Winner Unionville Heating
Reader's Choice 2022 Unionville Diamond Award Winner Unionville Heating

Local HVAC Contractor Unionville Heating and Air Conditioning Ltd. named Best of the DIAMONDS in the Readers' Choice Award for 2022

In a community where reliable and efficient heating and air conditioning and ventilation systems are essential for comfortable living, Unionville Heating and Air Conditioning Ltd. has stood out as the best HVAC contractor in Stouffville, Markham, and Unionville.

For the 22nd consecutive year, the company has been named the Best of the DIAMONDS in the Readers’ Choice Award for 2022. This award is a testament to the local business’s exceptional services to its clients.

The Readers’ Choice Awards, held annually, allow residents to vote for their favourite local businesses and professionals across various categories. Unionville Heating and Air Conditioning Ltd. was recognized for its top-notch heating and air conditioning services, which have undoubtedly earned the loyalty of its clients.

In accepting the award, the owner of Unionville Heating and Air Conditioning Ltd. expressed his gratitude to their customers for their unwavering support and loyalty, stating that the award would inspire them to continue providing the best services possible.

The achievement of Unionville Heating and Air Conditioning Ltd. in the Readers’ Choice Award for 2022 highlights the company’s commitment to excellence in providing its customers with the best possible HVAC services in the region.

Heating and Air Conditioning - How Can We Help You?

  • First check to make sure the batteries in your thermostat are good and it is set to heat.
  • Check the temperature setting.
  • Open the thermostat and gently blow out any dust or debris. Make sure it’s level and firmly attached on the wall, and that none of the wires coming into it are loose.

Call us to schedule an appointment for our HVAC Service Technician to diagnose and repair your furnace.  You can also book online here.

Call us 905-479-1290 to schedule a time when we can come out diagnose and repair your furnace.

Contact your local natural gas supplier or call 911. Never use your phone or other electronics near a suspected leak—If you suspect a gas leak in your home, go outside and at a safe distance from your home to use your phone to call your gas service or 911. If leaking natural gas is burning, call 911 do not attempt to put the fire out yourself.

  1. Shut Off System – Look for a shutoff switch, which looks like a light switch next to the furnace, and switch it off. If you cannot find this, shut off the system at the breaker.
  2. Clean Up Water Quickly – Sitting water will do quick damage to whatever it touches, so be sure to soak it up quickly.
  3. Check Filter – Make sure no airflow through the filter is not affected by water.
  4. Place Vacuum Around PVC Drain Line – Using a water-safe vacuum (i.e. Shop-Vac®), remove any debris and potential clogs. Afterward, turn on the air conditioning system and monitor this fixed leak.
  5. Pour Water Into Top of Condensate Pump – If the condensate pump does not react, it indicates a mechanical failure. If it does pump the water, then the drain line from the pump to the drain (or wherever water gets dispersed) is clear.

Repair Furnace

Fix a Furnace. No Heat? Schedule a service appointment.

Buy New Furnace

Choose a New Furnace. Replacing an old unit? Get the right one. Purchase here.

Community We Service

We have seen many changes over the years; however, the biggest change for us to date has been relocating our Highway #7 offices after three decades. We have a suite in Stouffville, and have created an accessible online presence that provides our customers with 24 hour access to all our services.  As a result, even in the middle of a cold night or during a hot humid day, we are here for you! To celebrate serving the community for over 38 years we offer our exclusive annual service programs for our neighbours or friends. “We Care”.

Big We Care Heart of Unionville Heating and Air Conditioning

We Care

For the reason that we care about your heating, cooling, recycling, and overall needs. You are encouraged to fill your empty new product box and we’ll take it away for you to your preferred Value Village, goodwill or food bank.

Professional Heating and Air Conditioning Service

Being comfortable with your home air quality and temperature is not just having a system that works, but knowing who to call when something isn’t working correctly. Therefore, if you’re having an issue with your air conditioner or furnace in Markham, Stouffville, Uxbridge, Unionville, Pickering, Ajax, Whitby, Oshawa, Brooklin or Aurora give us at a call at 905-479-1290 or schedule your appointment online. One of our technicians will soon be on the way.

What We Do for Our Customers

Unionville Heating and Air Conditioning company in Stouffville.

We serve the residential market only, and exclusively to the Markham, Unionville and Stouffville  and surrounding areas, for over 38 years.


Residential home Heating Ventilation and Air Conditioning systems installation, service and maintenance programs.

Green Recycling

You will not have any old parts to clean up. We’ll deliver waste materials to the proper recyclers.

Duct Work

Ductwork design and installation provide the optimum airflow needed to properly and quietly heat and cool your home.

Air Quality

Clean air is essential for good health, and this is especially true when it comes to indoor air in your home.

4 Great Reasons

To Choose Unionville Heating and Air Conditioning Ltd. for your HVAC service, repair, maintenance or installation.


38 Years In Business

Providing home heating and air conditioning solutions to the Unvionville and surrounding area.


Reliable Expert Installers

Our technicians are highly trained and experts in HVAC service and replacements. Therefore we guarantee to do the job right the first time.


15,000 Customers

Customer satisfaction is our number one goal. Most importantly, providing excellence in customer care and product knowledge has earned our great reputation for quality. As a result, the word travels in our community.


Live Telephone Attendants

As a consumer, there is nothing more frustrating than trying to get a live person on the phone when you have a home air heating or cooling emergency. For that reason, our staff are on the line.

What Customers Say About Us

We value the feedback we receive from our Customers and appreciate hearing how we can improve to better support your needs.