Can I back out if the installer is already here?

Almost always yes — if you signed in your home (door-to-door sale) and you are still inside the federal 3-business-day rescind window. The installer arriving does not extend the clock and it does not start over.

What do I say at the door?

Politely tell the installer you are exercising your federal cooling-off right and are not authorizing installation. Hand them a written cancellation notice (or text it to the rep). Send certified mail to the company headquarters the same day.

Will I owe anything if I rescind on install day?

If you rescind within the federal 3-business-day window, no — the company must refund any deposit within 10 business days and must remove any equipment they have already attached at no cost to you.

The Installer Is at My Door — Can I Still Back Out?

Short answer: yes, in almost every case. If you signed in your home and you are still within three business days of signing, the FTC's Cooling-Off Rule lets you rescind the entire contract for any reason. The installer arriving does not change that.

Here is what to do, in order, in the next 30 minutes.

1. Do not let installation start

The single most expensive mistake at this stage is letting the installer drill, mount, or activate anything. Once equipment is installed, the conversation shifts from "rescind" to "uninstall and dispute" — both of which are slower and messier.

Tell the installer at the door:

"I am exercising my federal three-day cancellation right. Please do not begin installation. I will email the company and follow up by certified mail today."

That is it. They are not allowed to talk you out of it.

2. Send written cancellation today

Federal rescind requires written notice. Email the rep AND the corporate cancellation address on your contract. Keep it brief:

"I am cancelling the agreement signed [date] at [address] within the federal 3-business-day cooling-off window. Please confirm refund of any deposit and removal of any installed equipment at no cost."

3. Send certified mail the same day

This is the proof the company cannot dispute. Certified mail to the address listed under "Cancellation Notice" on your contract. The receipt is your timestamp.

4. Run your contract through the Contract Analyzer

Before the installer leaves, paste your contract into the free Contract Analyzer. It checks the rescind clause, the equipment-loan separation, the auto-renewal language, and the notice-period clauses — and gives you an A–F grade in 10 seconds with no email required.

When the 3-day window does NOT apply

Sale was at the company's office (not your home).
More than three business days have passed since signing.
Some commercial / non-residential contracts.

If any of those apply, you are not out of options — see the Already Signed Escape Paths playbook for the next layer.

What about the installer's time?

You owe them nothing. The installer is paid by the security company, and federal cooling-off explicitly says you cannot be charged for "exercising the right to rescind." Be polite, be firm, do not sign anything they hand you.

Bottom line

Install day is the highest-pressure moment in the entire sales cycle by design. The fastest defuse is exercising the right you already had the moment you signed. Rescind in writing today, certified mail today, and run the contract through the analyzer so you know what else is in it.