How to Survey a House for an Intrusion System

Why this matters

Most install-day problems were made at the survey. A slider nobody noticed, a keypad at the front door the family never uses, a panel in a closet with no unswitched outlet and one bar of cellular, a motion detector quoted for a hallway the dog sleeps in. Each one costs a second trip, a change order the customer did not expect, or a system that false alarms until they stop arming it. A survey is not a count of doors and windows. It is a walk with the person who lives there, finding out how they move through the house, and ending with a zone list they have agreed to point by point, including what is deliberately left off.

What to settle before you drive out

A five-minute call saves twenty minutes on site. Ask:

• Who lives there, and who comes and goes. Kids with their own codes, a cleaner, a dog walker. Each needs a user code, and their routines decide entry delays and which door gets the keypad.
• Pets. Species, weight, whether they are crated, whether a cat climbs. This decides whether interior motion is possible at all.
• What prompted the call. A break-in nearby, a new house, insurance. A customer whose neighbor had a slider pried wants that slider covered more than anything else, and it should be first on the plan.
• Construction. Slab or basement, one story or two, finished attic or crawlspace. That decides hardwired versus wireless before you arrive.

Load the truck accordingly: contacts and a glass-break sample for showing, a cellular signal tester or a spare communicator to read signal, a tape, a clipboard or tablet with a blank plan.

The walk, in the order that finds the most

Outside first, alone or with the owner. Walk the perimeter and note every door and every window, including ones hidden behind shrubs, the basement windows at grade, the window over a low porch roof, and the door into the garage from the side yard. From outside you see what a burglar sees: which openings are out of the neighbors' view, which are reachable from a deck or a fence. Count them here; inside, furniture hides windows.

Inside, with the owner, door by door. At each exterior door ask: who uses this, when, and with what in their hands? The door the family uses every day, usually from the garage, is where the primary keypad goes, not the front door that only guests use. A keypad the owner has to cross the house to reach at the end of the entry delay is a false alarm waiting to happen.

Window by window. Note which windows are accessible: ground floor, below-grade, or reachable from a roof, deck or fence. Ask which ones they open, and when. A bedroom window a teenager opens at night cannot be armed in stay mode without a conversation; a window that is painted shut still gets a contact if it is accessible, because glass breaks.

The interior traps. Look for the path anyone entering from an uncovered or forced opening must take: the hallway between the bedrooms and the living area, the stair landing, the route from the slider to the rest of the house. That is where a motion detector or glass-break earns its place. The coverage geometry is its own subject; see related: Motion Detector Coverage and the Walk-Across Rule.

The panel and keypad spots. The panel wants a closet or utility space that is out of sight, inside the protected area, ventilated, near an unswitched outlet, and not in a garage that runs hot or freezes. Check the outlet is not on a switch and not on a circuit the owner turns off. Mark the primary keypad by the daily-use door and a second one at the master bedroom if they will arm at night from bed.

The cellular reading. Take it at the panel spot, with the closet door closed, before you promise anything. A closet behind a metal-framed wall or a basement corner can read far worse than the driveway. Compare the reading to the communicator maker's stated minimum; if it falls short, mark an alternate spot or an external antenna on the plan now. See related: Cellular Backup and Alarm Communicators.

Pets, from the owner's mouth. Where they sleep, where they roam when nobody is home, whether they are crated. Write the weight. Pet-immune ratings are per the maker, and a dog over the rating or a cat that climbs bookshelves rules out motion in that space no matter what the box says.

Worked example: a one-story ranch with an attached garage

A couple with a nine-year-old, a 45 lb dog that is crated in the laundry room when nobody is home, a slab house, finished drywall throughout. They called after a neighbor's slider was pried open. Slab and finished walls mean wireless sensors on a hybrid panel. Here is the plan as drawn on site:

 1-STORY RANCH, SLAB, ATTACHED GARAGE        (north up)
 +-----------+-----------+--------+---------------+
 | BED 2     | BED 1     | BATH   | GARAGE        |
 | (child)   |           | 1 high | overhead door |
 | 2 windows | 2 windows | window | NOT ZONED,    |
 |           |           | EXCL.  | owner agrees  |
 |           |           |        | side door D4  |
 +---   -----+---   -----+--  ----+---  ----------+
 | HALL  motion M1, corner, aimed  | door D3 into |
 |       across the hall           | house, KP1   |
 +---  -------------+--------------+-------  -----+
 | LIVING           | KITCHEN      | LAUNDRY      |
 | slider D2        | 2 windows    | PANEL closet |
 | glass-break GB1  |              | unswitched   |
 | 2 windows        |              | outlet, cell |
 |                  |              | -81 dBm      |
 +-- front door D1 -+--------------+--------------+
   KP2 at master bed for night arming (BED 1)

What the walk turned up that the call did not:

• The family uses D3, garage into house, every day. KP1 goes there; the front door D1 is guests only.
• The child's room has two windows, and she opens one in summer. In stay mode that window is a fault. The owners chose to keep it armed and close it at bedtime; the alternative, bypassing it nightly, was explained and declined.
• The bathroom window is 6 feet up and too small for an adult to climb through. Owners agreed to exclude it.
• The garage overhead door is not zoned: D3 into the house is covered, and the owners do not want the system armed against a door the opener controls. They agreed, knowing someone in the garage would not trip anything until D3.
• The dog is crated in the laundry when the house is empty, so motion M1 in the hall arms in away mode only. At night the dog roams, so M1 is not part of stay mode.
• Cellular read -81 dBm at the closet with the door shut. The communicator maker's minimum for this model is weaker than that, so the panel stays in the laundry closet.

The zone list built from the plan:

For what each zone type does when tripped, see related: Zone Types and What Each One Does When Tripped.

The finish test, applied. Count the openings from the outside walk: 4 exterior doors (D1 to D4), 9 windows (2 in each bedroom, 2 in the living room, 2 in the kitchen, 1 in the bathroom), and the garage overhead door, 14 in all. Covered by contacts: 4 doors and 8 windows, 12. Deliberately excluded with the owners' agreement: the bathroom window and the overhead door, 2. Twelve plus two is fourteen, so every opening is accounted for. The glass-break and the motion are backup layers, not coverage for any opening, so they do not count toward the fourteen.

The owners initial the plan beside each exclusion. That line is what settles it, months later, if someone comes in through the bathroom window and asks why it was not on the system.

Turning the survey into the job

The zone list becomes the install sheet. Each line carries the location name the central station will read to a responder, so write it the way a stranger would understand it: "garage side door", not "D4".

Note what the installer needs that the customer does not see. The outlet circuit, the closet's ceiling height for the panel can, the cellular reading and spot, where the dog is crated, which window the child opens.

Flag anything that routes elsewhere. Monitored smoke or CO detectors are fire-side work in many places; a new outlet is an electrician's where local rules require it. Name those on the survey so the quote does not promise what the shop cannot install. See related: Alarm and Low-Voltage Licensing Varies by State and City.

Where the survey changes shape

Two stories with a basement. Basement windows at grade are the most-used entry in many neighborhoods and the easiest to miss inside, because they sit behind stored boxes. The outside walk catches them. Hardwiring through an unfinished basement may beat wireless on cost and battery upkeep.

A large dog or climbing cats everywhere. No interior motion, and the glass-breaks and perimeter carry the system. Say so plainly at the survey rather than discovering it with a false alarm.

A customer who wants only "the doors". Write it, have them initial each window exclusion, and record that the choice was theirs. An entry point left off without a record looks like the installer's miss.

References

• See related: Motion Detector Coverage and the Walk-Across Rule
• See related: Zone Types and What Each One Does When Tripped
• See related: Cellular Backup and Alarm Communicators
• See related: Security + Alarm Systems Reference
• Communicator and sensor manufacturers' documentation for signal minimums and pet-immunity ratings