After being found guilty of a DUI, you may be required to have an ignition interlock device in your car, also called an IID. This type of device is sold by many companies, so you probably will find multiple options that fit your car. Finding one that is reliable and not too expensive is a good idea, as is picking one that is ISO 9001 certified. If you’re required to get one, check out this guide to some of the cheapest ignition interlock devices you can find.
What Is an Ignition Interlock Device?
An IID is a small, handheld Breathalyzer for car ignitions. Once installed, the ignition interlock requires the user to breathe into the apparatus to confirm their blood alcohol content. If alcohol is detected, the device will prevent the ignition from starting the vehicle. The Breathalyzer is usually broad and easy to hold and has a button for ignition you can use after your breath reads clear.
How to Choose an IID: What You Need to Know
Like having a broken ignition switch, an interlock device stops you from starting your vehicle. Unfortunately, if you’re after the cheapest ignition interlock device, most companies won’t list a price until they know your location, as the different laws and rules in each state lead to different expenses on their side. Still, there are a few tips to keep in mind when shopping for an ignition interlock device. Here are some of the key factors to consider when choosing an IID:
Make Sure Your Provider Is State Approved
Before you order a device or book an installation appointment, check that your state’s department of transportation or motor vehicles approves your chosen provider. The paperwork you received mandating you to get the device should also list the providers you can use. Devices by other providers will not count.
Try to Find a Nearby Installation Shop
Ignition interlock devices are not a DIY job. Since IIDs are required by court orders due to alcohol-related traffic offenses, you will have to have a professional third party install one. It’s a good idea to find a shop that can install the device for you and is relatively close by since you’ll have to return every month or two for a calibration.
Make Sure You Get an ISO 9001-Certified IID
One thing you should always remember when getting an ignition interlock device is ISO 9001 certification. The ISA is an industry authority on quality management, and products with ISO 9001 certification meet or exceed the expected quality standards for the industry in which the product is sold. Put simply, IIDs that are ISO 9001 certified are guaranteed to be of good or excellent quality.
With these tips in mind, here are some of the highest-rated and cheapest ignition interlock providers, with devices and installation that are likely to save you more money. Please keep in mind that ignition device providers are often state-specific or region-specific, so make sure any device you’re thinking of buying is approved to fulfill your state’s IID requirement.
Top Pick #1: Intoxalock
A top-rated provider, Intoxalock can provide interlock devices that meet your state’s regulations, all at a competitive price. Their team has state specialists who can answer your questions 24/7. Some benefits of choosing Intoxalock are:
- More installation locations in the United States than any other national provider.
- Discounts for voluntary device installation and more that vary by state.
- Simple pricing and flexible payment options.
Top Pick #2: Guardian Interlock
Another top-rated provider, Guardian proudly calls itself the most affordable ignition interlock provider serving most of the West and much of the eastern United States. Some advantages of choosing them are:
- Same-day purchase and installation with a free electrical systems check.
- Low monthly rate for all future checks and services.
- 24/7 bilingual customer service.
Top Pick #3: Smart Start
Started in 1992, Smart Start can provide IIDs at locations in nearly every state. Some benefits of getting a Smart Start ignition interlock device are:
- Flexible payment options, including autopay.
- Disaster and Covid assistance hotline and services.
- Skipping check-up appointments and mailing your IID modules with the new FLEX IID.
Our Methodology
Usually, you won’t be able to get an IID installed by yourself or purchased from a third-party site since it’s a legally sensitive matter. When shopping for an IID, providers usually sell their starting interlocks in the same price range. However, some companies are considered more affordable in the long term, with fewer fees and more options to save money. Some ignition interlock device providers are known to have few customer service and that can install their devices in most parts of the United States.
Ignition Interlock Device FAQs
Here are a few common questions people ask about buying or using ignition interlock devices:
Does cold weather affect IIDs?
A quality ignition interlock should be able to work in very hot or cold weather. If it’s cold, you may want to do a warm-up breath or two into the device, slowly breathing into the tube without pressing the reading button. This helps the device warm up a little and can ensure it reads your breath at the correct temperature.
How often do you need calibrations and what are they?
Calibrations involve a service center checking your IID’s data and condition. The new FLEX model by Smart Start lets you skip this by mailing the removable data modules and exchanging them with new ones sent to you. Otherwise, the appointment should only take about 15 minutes. Usually, calibrations are required every one to three months, depending on the state. You are legally required to get calibrations done somehow, so try to never miss an appointment and reschedule as soon as possible if you do.
Should I tell a mechanic that my device has an IID?
Yes, whenever you book any sort of auto service job, it’s worthwhile to let the company know that your car is equipped with an ignition interlock. It shouldn’t block you from getting the most common auto service or repair tasks done, but you should always check with the service shop. Also, try to save your receipts and other information about any auto service work, as these prove you are looking after your vehicle.

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