In brief
When somebody says “I want an alarm”, they are usually thinking of sensors, and sensors are only the first of three things that have to happen: something has to be detected, somebody has to confirm it, and somebody has to turn up. The conversation mostly ends at the first. Here I write about the other two, about the layers of detection, and about a decision that is made before the plastering: whether your house can be armed when the internet is down, the power is off and the company that sold you the system is gone. Then comes a second question, just as practical and asked even less often – whose codes are in this system, and what can be changed in it without calling anybody out. I design, choose and supply the security measures for a house – the ones I would want if I were in your place – but here I write about principles, not about how the system is laid out in any particular house.
Detection, confirmation, response
Sensors show up on the floor plan; they can be counted and priced – which is why the conversation starts with them, and usually ends with them too. But the signal on its own settles nothing, because somebody has to check it, and then somebody has to turn up.
It is usually the last part that people have thought about least. The house has sensors, the sensors work, the siren wails – and nothing follows, because nobody agreed who drives out and how they will know it is worth it. I call that arrangement a doorbell. A doorbell is not worthless, because noise can cut somebody’s visit short and a neighbour will sometimes look out of the window; but nobody has promised anybody a response here, so there is no point counting on one.
Where the system is actually looking
Detection is built in layers, and that is the whole philosophy: the boundary of the property, the shell of the building, the inside. If the system only starts inside – motion detectors in the rooms, a few opening contacts on the doors – it will speak up only when somebody is already in the house, a few metres from the bedroom. Detection still happens; it just comes too late for much to be done about it.
Sensors outside make sense for one reason: they give the signal earlier, before anybody gets near the building. If the system detects someone while they are still at the fence, the whole time it takes them to cross the plot is yours – for the notification, for the check, for the decision. On a residence that can be a long way, and it is the only margin in the whole chain that you do not have to buy from anybody.
Outside, though, it is harder. Indoors you get false alarms too – a pet, a draught, a fireplace, a robot vacuum – but the environment there is incomparably more predictable. At the boundary of the plot you have a roe deer, the neighbour’s cat, a branch that keeps growing and after two years starts knocking against a fence panel (nobody thinks about it when the installation is handed over, because it is not there yet), rain, snow, and the sun rising straight into the sensor. A detector designed for indoors, taken outside unchanged, will go off for no reason until you switch it off, and then the first layer stops existing, even though on paper it is still there. Outdoor detection is designed differently from indoor detection; it is a separate piece of work and a separate item in the design.
There is one more thing the trade does not like to talk about: the language used to describe alarms stops at the wall of the building. The European standard everybody refers to covers indoor systems and explicitly excludes outdoor installations from its scope, and for detection at the fence itself there is no harmonised standard that would describe it the way the grades describe the system inside. It is still worth doing; it is only that at the fence nobody will hand you a number that settles everything, so the requirements, the working conditions, the false alarms and the response procedure have to be agreed separately.
The glazing decides where the system has to work
This is where a residence differs most from an ordinary house, because there is a lot of glass: whole walls, sliding panes, glazed corners. Locks and doors are usually the strongest part of the shell, and they are what everybody prices most carefully, which is why the place where the system has to work is set by the glass, not by the doors.
On top of that comes a distinction that changes everything in a house with walls of glass: opening a leaf and going through the pane are two different events. They are detected by two different methods, and the technical guidance to the standard treats them separately. In practice it means that if the shell relies on opening contacts alone, the house can have them on every leaf and still not detect somebody going through a broken pane.
There is a consequence to this that people usually think of too late. With burglar-resistant windows the options are glass of a suitable class, burglar-resistant hardware and factory-fitted opening sensors that are wired into the alarm installation – and all of that is an item in the window quote, not in the alarm quote. So the decision about the first layer of the shell is made when you choose the windows, not when it is the alarm’s turn to be installed. Adding sensors later, surface-mounted, is of course possible, and sometimes that is how it ends; then you can simply see that somebody was late.
Why one signal is not enough
A system that goes off every week for no reason stops existing, and it does not have to break for that – it is enough for people to get used to it. The neighbour stops looking out of the window, the security company treats the next call from that address like the last one, and you yourself, after three false alarms in a month, stop arming the house when you go out for an hour. People have to trust the alarm before they will respond to it; without that trust, all you have is noise.
Hence the rule everything else stands on: two independent events mean more than one. If something was noticed in two places, or by two different methods, the certainty goes up, and only then does it make sense to involve people. Monitoring stations distinguish a confirmed alarm from an unconfirmed one precisely because somebody has to decide whether to send a patrol. Outside, there is nothing to discuss without that rule, because with a single sensor on the fence the wind and the deer will get into the statistics sooner than any person.
This is as far as I will go in public: principles can be described, the layout of a particular house cannot, and I explain why in the text on residence security in layers.
Whose system is it, really
An alarm has one feature that sets it apart from the rest of the house: it has to work when other things fail. That is why the question “what does this system depend on” matters more than the question “what can this system do”. There are three dependencies, and each of them can quietly take away part of your system.
The first is somebody else’s server. In some of today’s solutions, especially the good-looking ones with an app, the panel in your plant room talks to the manufacturer’s server, and you talk to the same server from your phone. The convenience is real and I have nothing against it, but this is where the line runs, and you have to ask about it directly, because the brochure does not show it: in some systems the app is only an extra and you arm the house on the spot whatever the network is doing, while in others that server sits in the control path. Then arming your own house is a service provided by a company somewhere else, operating under different laws and under no obligation to you to keep that service running for any particular length of time. That server runs for as long as it pays somebody to keep it running, and when it stops, a perfectly good device on your wall loses the part of its functions that went through it: sometimes only the app and the notifications, sometimes everything. That is not a fault; it is the end of support. And nobody has to ask your opinion.
Companies go under, get taken over, change their model, and the house stays where it is – equipment bought for a residence is meant to keep working longer than many a start-up. So I put the requirement simply: the system has to work without the internet and without the manufacturer’s server. Arming, disarming, detection and signalling have to happen on the spot, in the house, without asking anybody’s permission. Notification is the one element that by its nature has to go outside, and that is exactly why it needs its own, independent path – more on that in a moment. Remote viewing is fine, provided it is an extra and not a condition of the system working, and provided the channel belongs to you.
The second dependency is codes and accounts. Service access is something different from the owner’s access, and the conversation about it should take place when the installation is ordered, not after handover. Everybody has as much access as they need for their own work, and once the house has been handed over, only you have access to the alarm, until you give it to somebody yourself; whoever was given access for the duration of the works loses it when the works end.
The third dependency is the most everyday one, and it is the one that most often decides whether the system gets used at all: what can be changed in it without calling anybody out. The owner should be able to change simple settings without help and without the risk of breaking something. The reason is practical. An alarm that gives you 30 seconds to get out of the door is bearable for the first week and then becomes a torment. If changing those 30 seconds to 10 minutes means booking the installer, agreeing a date and letting him into the house, nobody will do it. Instead, the house stops being armed day to day and gets armed once a year, for the holidays. The system works, it cost what it cost, and for most of the year it protects nothing, because it gets in the way.
And these are entirely ordinary things: how much time you have to get out, how you arm the house for the night, and who gets the notification.
Cutting the system off from somebody else’s server does not make you safe; it removes one way in, the remote one. The physical way in remains, and the rest of this text is about that.
Blinds, lights and the alarm
Home automation today can control the lighting (every bulb separately), the sockets, the blinds, the entrance gate and the heating, as well as the ventilation, the air conditioning, the cameras and the alarm. In short, everything in the house. Precisely because it can do everything, this one thing is better not handed to it.
Blinds are meant to be convenient and an alarm predictable; those are two different aims, and you see the difference most clearly in the people who work on each system. An automation system is a living thing: after the move somebody tunes it, and then comes back to it many more times, because the children, the furniture and the household’s habits change. That is automation’s strength, because it is meant to be tuned. Just think for a moment what it means if the alarm sits on the same bus: the same person who adjusts the lighting scene in the living room then has access to the layer the alarm panel works in.
There are no bad intentions in this, only a rule that is applied wherever something matters: everybody gets access to what they need for their work, and to nothing more. The engineer who services the lights does not need the alarm to do his job, and should not get it thrown in.
Then there is something clients usually do not know: the certification of automation devices is mainly about whether they talk to each other properly, while alarm components are certified for tamper resistance, line supervision and alarm procedures. That does not make them worse; they simply do a different job.
That is why the two systems are run separately and joined at one defined point of contact: the automation sees only what somebody deliberately showed it, and a failure of the automation has no effect on the alarm. That decision belongs to the installation design stage, because two systems mean two cable routes. I write about the automation itself, and about what has to be settled before the first back box goes in, in the text on home automation.
That separation has its price: sensors are duplicated, there is more cabling, and sometimes two scenarios have to be reconciled so that the lights do not come on while the alarm is armed. It looks excessive, and I understand the objection. I think it is worth it, but I want it to be your decision, made knowingly.
Power and the line
In a serious scenario you have to assume that the power and the line may be the first things to go. That is no secret, and nobody in the trade pretends otherwise, which is why back-up power and a second, independent notification channel are not top-of-the-range extras but what it takes for the system to work at the one moment it is needed.
There is a mechanism here I like more than anything else in this field, because it is the opposite of what you would expect. If the transmission path is supervised, the line speaks up by itself: the panel and the monitoring station keep exchanging a regular heartbeat signal, so cutting the cable or jamming the network does not silence the system; it wakes it up. The absence of a signal is the signal. The condition is a hard one, though: the path has to be supervised and the station has to have a procedure for loss of contact, and you have to ask about that directly, because from the outside such a set-up looks exactly like one that will simply go quiet.
Who actually turns up
I ask this question at the start, although in conversations it usually comes back at the very end. The parameters of the sensors can be chosen and set, but that is still only technology; the measure of a system is who turns up, and after how long.
The answer depends on where the house stands. With the residences I build outside towns, the real time it takes to get there can be nothing like the owner’s picture of it, and it is better to check that at a stage when something can still be done about it than to find out later. The contract with the monitoring station is a separate subject and a separate document; that is where it says what actually happens after the signal, so read it more carefully than you usually would.
The people on the list belong to the system too: a neighbour, a brother, somebody who has keys. They are part of the system only if they know what to do, because a person who gets a notification and has no idea whether to drive over, phone or wait simply gets anxious, and that is all that comes of it.
Detection buys time, and you have to have something to spend that time on. This is where the conversation about barriers and escape routes begins, and at the end of it stands a panic room.
When to decide
An alarm and cameras are extra-low-voltage installations, so the cable routes are made together with the electrical installation, before the plastering. After that every change costs something: sometimes chasing the walls, sometimes visible trunking, sometimes a compromise. I write about the cameras themselves – where the footage goes and why it should not leave the plot – separately, in the text on home CCTV.
With ordinary houses I repeat the simplest thing there is: while the cables for the electrical installation are being run, it is worth considering running the cables for an alarm or cameras as well. The sensible thing is to bring all of them to the loft, the boiler room or a utility room – wherever the alarm control panel and the CCTV recorder could go. It should not be a big cost. If in the end you decide not to fit anything, the cables disappear under the plaster, and they can be used in the future if the need arises.
That advice does not change. On a residence it simply stops being enough, because it has to be joined by things that cannot be run just in case: sensors in the window frames, ordered together with the windows, power and cable routes at the boundary of the plot, a second route for a system that is to be independent of the automation. All of those are design decisions.
What can be run just in case is cheap before the wall is plastered: an empty duct and a few more metres of cable cost next to nothing then.
With an alarm, things are a little easier – in principle we do not have to decide early on whether we want one at all, because there are plenty of wireless systems on the market and the batteries last quite a long time. On a residence that option becomes more limited, because the larger the first layer and the further it extends outdoors, the more things need a cable and power. Then it is I who require the cable, even though not every system needs one.
When it is not worth it
I start the conversation by asking what you are really afraid of, because that decides how much of the house needs to be covered by detection at all.
A simpler arrangement can give the same result. I have been saying this for years, and I do not take it back for bigger houses: in my view even the simplest alarm system puts off would-be burglars and helps you sleep soundly while you are away for longer, on holiday for instance. If the house stands empty for a few weeks a year and that is the whole problem you have to solve, you do not need three layers of detection. Whether an installation makes sense at all depends entirely on your preferences and on the area where you are building. The question only changes when the house is not empty, because then deterrence settles the smaller part of it.
It also happens that the alarm is the answer to the wrong problem. Sometimes the real problem lies somewhere else entirely: people can walk onto the property as if into a park, or the family has a routine you can read from the street a mile off. No system fixes that, and an elaborate alarm can drown that conversation out very effectively.
Nor is it worth it when the alarm is meant to replace a barrier, because it will not: detection tells you that something is happening, but it does not delay it by a single second. Delaying it is the job of the fence, the windows and doors and the structure; the alarm is there so that somebody finds out.
About the cost, one thing can be said that does not depend on any price list: the biggest difference comes not from the equipment but from the moment of the decision. A system planned before the plastering costs a different amount from one added later, and a great deal can be done in a finished house, as it regularly is – but at a cost that could have been avoided.
I do not promise that the system will detect every scenario, nor that a local installation is resistant to everything, because it is not; it is only independent. Nor will I tell anybody, publicly or privately, what solutions of this kind look like in particular clients’ homes.
What I ask before I say yes
- What exactly is this system meant to defend against?
- Can the house be armed and disarmed when the internet is down and the manufacturer’s server has been switched off for good?
- Which layers are we doing – the boundary, the shell, the inside – and what happens when the first one speaks up?
- Does the alarm share a bus with the home automation, and if not, where do the two meet?
- Who has service access to the alarm and who to the automation, what is left behind when the service engineer leaves, and what can be changed without calling him back?
- What does notification look like when the power and the network are down, and is the line supervised?
- Who comes out, how do they know it is worth it, and how long does it really take them to reach the gate?
- Who in the household and on the contact list knows what to do when the phone rings at three in the morning?
Frequently asked questions
Will the alarm work when there is no internet?
It will, provided somebody required it when the installation was ordered. A local system does not need somebody else’s server to work: you arm it, disarm it and hear the siren whatever the network is doing. Only the notification has to go outside, and that is why it needs its own, independent path; that is a separate question to ask. The difference shows on the day the manufacturer switches the service off – a local system simply does not notice that day.
Does an alarm have to be planned before the build, or can it be added later?
The alarm itself can be added later, wirelessly too, and on an ordinary house that is a sensible route. Before the plastering, though, decisions are made that cannot be reversed without chasing walls: the cable routes, sensors ordered together with the windows, power outdoors, and running the alarm separately from the automation. The more of that you want, the earlier the subject has to come into the conversation with the designer.
Which security grade should I choose for a house?
I do not settle that in a text or over the phone. The grades in the standard describe not so much the equipment as the intruder you can expect – his knowledge and his tools – so I choose the grade for a particular house and for what the system is meant to defend against: at a meeting, not in an article. The grade itself is a shared language for the client, the designer, the installer and the insurer; it is declared for the whole installation, not read off the brochure of a single device.
Does detection at the fence make sense on a large plot?
It does, provided somebody has worked out what happens once it is triggered, and provided you are prepared for false alarms, because outdoors there are more of them and it will stay that way. The deer, the wind and the growing branch are real players in this system. Detection at the boundary of the plot makes sense when it turns into time that somebody will actually use.
I have collected answers to common questions about privacy and discretion in the Questions section.
If you are thinking about a house in which these decisions are to be made in good time, the place to start is before the installation design exists. Let’s talk about your project.