Definition — what 'proper install' actually means
A proper central AC install is more than dropping in a condenser and connecting the line-set. It includes: a Manual J load calculation to size the unit, a Manual D check that your ducts can move the required airflow, refrigerant charge verified by measured superheat and subcool (not 'topped off by feel'), static pressure measured across the coil, and a written commissioning sheet handed to the homeowner.
That is the level of work manufacturers assume when they publish SEER2 ratings and 10-year warranties. Skipping any of those steps quietly voids the warranty and undercuts the efficiency you paid for.
When to use this checklist — before signing any quote
Ask every contractor bidding your job the same six questions. If any installer answers 'we always do 2.5 tons for this size house' without measuring, that's a red flag — real load calcs vary widely by house.
- Will you do a Manual J load calculation? (If no, move on.)
- How will you verify refrigerant charge on the finished install?
- Is your gas technician TSSA G2 or better? (Only if a gas furnace is part of the job.)
- Will you pull the required municipal building/mechanical permit?
- What's your written warranty on labour vs parts vs compressor?
- Are you an authorized dealer for the equipment brand you're quoting? [CONFIRM: authorized dealer status]
Failure modes — the classic bad-install patterns
The most common failure we see is an oversized AC on undersized ducts — the coil freezes because there's not enough airflow, the compressor short-cycles, and the homeowner blames the brand. It's not the brand; it's the design.
The second most common: a mini-split installed with sub-flush line-set covers that trap water against the exterior wall, causing rot behind the head. Line-set penetration is a place where a $30 fitting decision determines a $30,000 exterior repair five years later.
Third: a condensate line dumped into a mop basin with no P-trap, so sewer gas backdrafts up into the mechanical room every time the furnace fires.
Proof — what to keep on file after the job
A trustworthy installer hands over a job packet: signed permit, commissioning sheet with static pressure and refrigerant charge numbers, warranty registration confirmation from the manufacturer, and a photo record of the finished install. Keep this — it's what a future buyer's home inspector will want to see.
If the installer 'forgets' the permit or asks you to skip it 'to save $500,' you have the wrong installer. Municipal permits and ESA/TSSA inspections are homeowner protections, not paperwork.
Action — how to interview a Scarborough / GTA AC installer
Get at least three quotes. Reject any that skip the site visit — no reputable installer quotes a full AC replacement over the phone. Ask each to write the six answers above onto the quote. That single request weeds out most fly-by-night operators.
When you're ready, call Metroheat at (416) 283-5698 or book online. We'll walk your home, run the numbers, and hand you a written comparison in plain English.