How much does a house alarm cost?

Number of sensors and detectors

Every door and window you want to protect typically needs a contact sensor. These detect when the door or window opens. Most homes need 8-15 of these. Motion sensors detect movement inside rooms - you might need one per floor or one per main room, depending on the system design and your property layout. More entry points and larger properties mean more sensors, which increases both the upfront hardware cost and potentially the installation time.

Glass break detectors are optional extras that listen for the sound of breaking glass. They provide an additional layer of protection for windows, especially large ones. Some systems include these as standard, others charge per detector.

Camera requirements

Cameras add significantly to costs. Indoor cameras typically cost £50-150 each, outdoor cameras £100-300 each. Beyond the hardware cost, cameras affect monitoring prices - some professional monitoring plans charge extra for video verification or cloud storage of footage. Even self-monitored systems often have subscription tiers for video storage (free for basic, £5-10/month for longer history or more cameras).

Consider whether you need cameras at all. Many effective alarm systems use only sensors and detectors. Cameras are most useful if you want to verify alerts remotely, deter opportunists with visible cameras, or capture evidence if a break-in occurs.

Installation method

Professional installation typically adds £200-500 to the upfront cost, though some providers include it in package prices. You're paying for the installer's time (usually 3-6 hours), their expertise in positioning sensors optimally, and the convenience of not doing it yourself. Professional installation often comes with a guarantee - if something doesn't work properly, they'll return to fix it.

DIY installation costs nothing beyond your time, but you're responsible for positioning sensors correctly. Modern wireless systems are designed to be DIY-friendly - most sensors stick on with adhesive or need just a couple of screws. The trade-off is that you might not position sensors optimally, and you'll need to troubleshoot any issues yourself.

Type of monitoring

This is usually the largest ongoing cost difference. Professional monitoring (£25-40/month) means a 24/7 alarm receiving centre responds to alerts, verifies them, and contacts emergency services if needed. Self-monitoring (free to £15/month) sends alerts to your phone - you decide whether to check cameras and call the police yourself.

Some systems offer optional professional monitoring - you can start with self-monitoring and upgrade later if you want. Others, particularly installed systems like Verisure, include professional monitoring as a mandatory part of the service. The monitoring type significantly affects whether you need a contract and what the minimum term might be.

Contract length and equipment ownership

Professional monitored systems usually require a minimum contract, typically 12, 24, or 36 months. Longer contracts may offer lower monthly rates but less flexibility to leave if your circumstances change. DIY systems with optional monitoring tend to offer month-to-month plans or no contract at all.

Equipment ownership matters for your total cost. With some providers, you pay upfront and own the kit - if you cancel, you keep it (or can take it when you move). With others, the provider owns the equipment - your upfront cost is lower, but if you cancel, they may collect the kit. This particularly affects "from" prices that seem low upfront but include mandatory monthly fees for equipment rental as well as monitoring.

Typical minimum contract terms

Professional monitored systems usually require a minimum contract. Twelve months is most common, though some providers offer 24 or 36-month contracts (sometimes with lower monthly rates for longer commitments). The contract covers the monitoring service and, with some providers, equipment rental.

DIY systems with optional monitoring tend to be more flexible. Many operate on a month-to-month basis with no minimum term - you can cancel anytime. This flexibility is one reason people choose DIY systems even if they pay for optional professional monitoring on top.

Early cancellation fees

If you want to leave during the minimum term, most providers charge an early termination fee. This typically covers some or all of the remaining monthly payments. For example, on a 12-month contract where you've paid for 6 months, you might owe another 6 months of fees (or a percentage of them).

Some providers own the equipment and will collect it if you cancel. Others let you buy out the equipment value if you want to keep it. A few require you to return equipment but don't refund any upfront costs. These details should be clear in the contract terms - if they're not, ask before signing.

Be particularly careful with contracts that auto-renew. Some continue month-to-month after the minimum term, others automatically renew for another fixed term unless you give notice. Check what notice period you need to give and set a reminder.

Your cooling-off rights

Under the Consumer Contracts Regulations 2013, you have a 14-day cooling-off period for contracts agreed at a distance (phone, online) or off-premises (like a home visit). During this time, you can cancel for any reason and get a refund.

However, this right is lost if installation has started with your agreement. Many professional installation providers will ask you to sign a waiver acknowledging this, as they need to start work before the 14 days are up. This is legal and common - just know that once installation begins, you're committed to the contract terms.

Price increases during the contract

Many alarm contracts allow the provider to increase the monthly price during your contract term. This is usually linked to inflation (RPI or CPI) and capped at a certain percentage. Read the small print - some contracts allow increases of RPI plus 3-5%, which can add up over a multi-year term.

If price increases aren't acceptable to you, look for providers that fix the monthly cost for the entire minimum term. These are less common but do exist, particularly among smaller or newer providers trying to differentiate themselves.

What to ask before you sign

• •What is the minimum contract term? Get this in writing.
• •What happens if I cancel early? Ask for the exact formula they use to calculate cancellation fees.
• •Who owns the equipment? Do you keep it, return it, or buy it out if you leave?
• •Can the monthly price increase? If so, how and by how much?
• •Does the contract auto-renew? What notice period do you need to give?
• •What does "minimum term" actually cover? Just monitoring, or also equipment rental?

1. Understand "from" prices

When you see "from" on a price, it means that's the starting point for the most basic system. Your quote will likely be higher if you need more sensors, cameras, or coverage than the starter package includes. Providers use "from" prices honestly - the cost genuinely varies based on what your home needs.

Our calculator shows you what's included in the starter package and compares it to what you've told us you need. If there's a gap (for example, the starter has 1 door sensor but you want 4), we tell you the real quote will be higher. We don't guess at the extra cost unless the provider publishes unit prices.

2. Factor in what's not included

Our estimates typically cover hardware, installation (where applicable), and basic monitoring. What they might not include:

• • Optional extras like glass break detectors or additional keypads
• • Premium features like video storage or advanced app access
• • Call-out fees or guard response charges (if they're not included in monitoring)
• • Installation of additional sensors you decide to add later

When you request actual quotes, ask providers to itemise everything so you can see what's included and what costs extra.

3. Look at total cost of ownership

We show 12, 24, and 36-month totals because looking only at upfront cost or monthly fees can be misleading. A system with low upfront cost but high monthly fees can end up more expensive over time than one with higher upfront cost but lower monthly fees (or no ongoing cost).

Consider how long you plan to keep the system. If you might move house in a year, total cost over 12 months is what matters. If you're settled long-term, look at 36-month totals and beyond.

4. Compare like with like

When comparing providers, check what each price includes. Professional installation plus professional monitoring isn't directly comparable to DIY installation plus self-monitoring. Both can be right choices, but they're different products at different price points.

Our comparison pages break down what each provider offers so you can see the differences clearly. Use these to understand what you're paying for, not just which number is lowest.

5. Request actual quotes

Once you've used our calculator to understand the likely cost range, request quotes from two or three providers. Give them the same information (number of doors, windows, whether you want cameras, etc.) so quotes are comparable.

When you receive quotes, check them against our estimates. Significantly higher? Ask the provider why. If our estimate is higher than their quote, that's good news - you've got a better deal than we expected based on published prices.