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3500 Sq-ft shop Heating

BuddyHughes Member Posts: 1
Hey everyone,

I hope this is going in the right place, I own an Automotive repair shop in Toronto, it gets awful hot in the summers and winter it gets so chilled cold. So I want to put AC in the shop for my guys and the customer's cars. The issue is I am getting Estimates that are VERY far apart and the guys who come out to give the bids, don't seem very sure about what they are quoting. Recently I have been called by an industrial heating service. I haven't spoken to them until I get an opinion from you guys. The building is brand new, insulated very well on the sides and roof (Don't know what grade) 3500 sqft shop space, three roll-up doors, and 3 shop entrance doors. I currently have a 14' Big fan in the shop now. I've been told everything from a 5ton unit and if that doesn't work, they can add one more 5ton unit. Any thoughts or Ideas would be greatly appreciated so I can hopefully make an informed choice on who to go with.

Thank you!


  • Snowmelt
    Snowmelt Member Posts: 1,415
    since its a new building are you able to get blue prints are get the insulation value. since its a garage shop they should and will take in consideration that the doors go up once every 30 minutes for 5 minutes. you should ask for a heat load calculation. then go from there.
  • Ironman
    Ironman Member Posts: 7,376
    I haven't check on this for several years, but the mechanical code in the U.S. used to require 100% fresh air if you used a ducted system to heat or cool an automotive repair shop. This is another reason why radiant floors are desirable for garages

    Ductless units may be a way around this since ductless hanging heaters are allowed. I'd check with your code official and find someone whose COMPETENT to design it. A guy saying he'll put in 5 tons and if that's not enough he'll put in 5 more is not who you want.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Zman
    Zman Member Posts: 7,569
    A commercial garage should have a HVAC system that brings in outside air. https://www.engineeringtoolbox.com/garage-ventilation-d_1017.html
    This is both for the comfort and health of your employees and customers.
    Most manufacture reps have engineers on staff who are more than happy to assist with the design. Don't let the contractor guess at what is needed. Ask them to have the manufacture help get it right.
    My guess is that a rooftop AHU is going to be the easiest way to accommodate your heating, cooling and ventilation needs

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • John Mills_5
    John Mills_5 Member Posts: 951
    100% outdoor air would be a special unit made for heating & cooling that much outdoor air.