5 Best Mains Powered Smoke Alarms

Author: Reece Thompson | Updated on March 29, 2019

The quick answer is that the Aico Ei141RC is the best hard-wired smoke detector, in our opinion.

We have installed 12 15 sets of mains powered smoke alarms in the last 12 months, so we feel that we have the authority to tell you what works and what doesn't!

Before we give our five best hard-wired smoke alarm systems, we're going to reveal an overall winner, a runner-up, and one that you should avoid! Check out the table:

Our preferred mains smoke alarm is the Aico Ei141RC because it's reasonably priced, easy to set up and install, and has a 9-volt battery back-up in case of the mains power going down.

If you've got more time to read, we're happy to tell you that we're going to reveal five of the best interlinked types. We base our rankings on:

  • Price
  • Ease of install
  • Quality

Naturally, all the systems we've done have been professionally installed by a suitably certified electrician that is NICEIC qualified.

If you need something similar installing into your property, make sure the tradesperson you use is registered with NICEIC, Elecsa, Napit, or another recognised body. You can read more about competent persons here.

Top 5 Smoke Alarms - Ranked!

Now that you have our preferred option, what about the rest?

Often referred to as an interlinked system by those in the trade, we now give our opinion on the five best mains powered units available on the open market.

Please note, we discuss portable smoke alarms and smoke alarms for deaf people on other pages.

1. Aico Ei141RC Mains Ionisation

Our Rating: 4.4/5

Aico Ei141RC hardwired

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Amazon's Choice for "Mains Smoke Alarm"

  • Manufacturer: Aico
  • Weight: 349g
  • Size: 18 x 15.4 x 6 cm
  • Cost: £
  • Quality: Excellent
  • Installation: Easy

This one is our favourite. Easy to source, easy to install, and well priced. You can connect up to 20 of these, meaning they’re perfect for large properties. This can be done by hard wiring all the detectors or using the wireless capability, if the local council allows it.

It comes with a 9-volt battery back up in case the mains power goes down.

We made a mistake (or our electrician did) by putting an AICO heat detector in the bedroom instead of a smoke detector. Fortunately, you can use the same base and simply change the head, so it was a five-minute fix.

(Tip:  Read our guide on maintenance to combat potential fires.)


  • Excellent value for the price
  • Available to buy from almost all hardware stores
  • Can fit up to 20 of these together


  • Not a well recognised brand internationally
  • A bit bulkier than other brands

2. Kidde Firex KF20 Interlinked

kidde interlinked
Our Rating: 4.5/5

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  • Manufacturer: Kidde
  • Weight: 340g
  • Size: 8.3 x 7.4 x 2.9 inches
  • Cost: £
  • Quality: Very Good
  • Installation: Easy

Installation with this Kidde Firex detector is easy. If you position the baseplate mounting appropriately, it goes straight on.

If you have an older baseplate from Kidde, the screw positions are the same for the newer versions i.e., you can do a like for like head replacement.

Attach it on, and it locks in to place with a quick twist.

It comes with a 9-volt replacement battery, and the device won't allow you to mount it unless you put the battery in. How smart.


  • Can be interconnected with up to 11 FireX alarms
  • Unique “battery missing” lockout
  • Green light signal indicates it's receiving AC power


  • Some have complained of a chirping noise
  • It can be limiting if you have a bigger home
  • Kidde should supply a conversion matrix

3. Nest Protect 2nd Generation Smoke (Wired)

Our Rating: 4.5/5
nest wired smoke alarm

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  • Manufacturer: Nest
  • Weight: 460g
  • Size: 5.3 x 1.5 x 5.3 inches
  • Cost:££££
  • Quality: Excellent
  • Installation: Difficult

We've talked about this one in our guide to the best carbon monoxide detectors, and it deserves a place here too.

Yes, it is expensive, and it can be costly once you start connecting several units, but it is the most advanced smart device for home safety.

If you're looking to upgrade, a huge plus point is that the wired Nest system can be hooked into the previous electrical wired system. The only difference is that the thermostat will need an additional wire installed.

All you need is the 120-volt hot (black) and neutral (white) wires in the electrical box connecting to the plug-in pigtail on the Nest.


  • Very advanced, can be used with Alexa
  • You can interconnect and unlimited number
  • Constantly receives updates internally


  • Very expensive
  • Traditional systems can do the same job mostly
  • Will need a qualified person to install

4. First Alert SCO5 Hard Wired

Our Rating: 4.2/5
first alert sc05

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  • Manufacturer: First Alert
  • Weight: 295g
  • Size: 8 x 7 x 2.5 inches
  • Cost: ££
  • Quality: Very good
  • Installation: Easy

This is a combined smoke and CO alarm, which includes a battery back-up.

We used this model when we initially started refurbishing houses. We were subsequently  asked to supply the CO alarm separately, hence why we started using AICO ones instead.

It's a good one for homes and larger HMOs as you can hook up 18 compatible devices.

In addition to electrochemical sensors, the device can pick up on smouldering fires through its photoelectric sensor.

As a bonus, it comes with an 'end-of-life' battery signal meaning you can replace the entire unit with a brand new one.


  • Can connect to other BRK or First Alert detectors
  • 10-year limited warranty
  • Can be heard by those with hearing issues


  • It's quite expensive compared to others
  • Some users complain of false alarms

5. FireAngel WST-630Q Radio Interlinked

Our Rating: 4.3/5
radio interlinked smokes

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  • Manufacturer: FireAngel
  • Weight: 1213g
  • Size: 13.2 x 13.2 x 4 cm
  • Cost: ££
  • Quality: Very Good
  • Installation: Easy

Like the ones above, these are straightforward to install.

The difference is that they are radio interlinked, i.e., no need to be lifting floorboards, connecting cables, etc.

Be careful that you don't buy an older model. These tend to be the ones that people have been complaining about, which gives off a false alarm.

The current model replaced the older model of the same smoke detectors.

You can unscrew the old base plate and install the new ones. After that, connect them up wirelessly.

Check with your local fire risk assessor if they will accept radio interlinked alarms as not all local government housing departments do.


  • Tamper locking pins
  • Very light and easy to handle
  • Can fit up to 50 of these wirelessly


  • Older model isn't reliable
  • A few have complained of chirping alarms

Where to Place Hardwired Smoke Detectors?

As mentioned at the beginning of this page, we've done approximately 15 Houses in Multiple Occupancy (HMO) this past year.

One of the leading legal requirements when doing something like this is to install an interlinked system.

We always put smoke detectors in living rooms and bedrooms. Rarely do we put a heat and smoke detector into a bedroom as we don't offer cooking facilities in the bedroom, i.e., we run our HMOs on a shared amenities basis.

This means that all the cooking facilities are positioned in the kitchen. In this respect, we have a heat & smoke detector instead of a smoke detector in the kitchen.

As the wording suggests, these two types of detectors are interlinked. So if a fire starts in one room and sets off a sensor, the ones in every single other room will start beeping too.

How many smoke detectors should I have in a house?

Ideally, you want to place one smoke detector per floor.

How many should I have in a HMO?

You must install an interlinked smoke alarm in each bedroom and any shared living space. The kitchen should have a heat & smoke detector, which should be interlinked with the other smoke detectors.

As stated above, if the bedrooms have cooking facilities, you’ll need a heat & smoke detector.

Can I use different brand when linking up hard wired detectors?

It is a better idea to be consistent and use the same ones as they are designed to work with each other. It is not mandatory to do this; you can use different brands of hardwired detectors. Be warned that there might be compatibility issues.

Do I need an electrician to install hardwired smoke detectors?

Yes, 100%. It’s essential to hire a qualified electrician that can offer this service competently.

We’ve been paying between £1300 and £2200, including labour and materials for a full system installation. The larger the property, the more detectors are needed.

As per our suggestion at the very top, we bought some AICO Ei141RC units from Screwfix.

Remember, once you've bought some of these, it's not the end of it. It's vital that you or your agent knows how to maintain smoke alarms, wired or otherwise.

Radio vs Wired

Which interlinked smoke alarm system is acceptable for local authorities?

In some cases, local councils do not like the wireless type, so you’ll have to opt for the wired ones. Speak to your local authority about this, and the decision might be made for you.

Otherwise, both are acceptable, but to answer which is better depends on one principal question: Is it a complete refurbishment where you can rip up the carpets and floorboards, or are you looking to fit them retrospectively?

  • If it’s a refurbishment, opt for wired
  • If you’re retrofitting, opt for wireless

In terms of cost, there isn’t going to be that much of a difference (once you factor in the labour).

Radio Frequency Interlinked


  • Wireless are useful for linking two areas where it’s difficult to get a wired connection
  • no messing around and cutting out for wires and cables
  • Less labour costs


  • Wireless ones can bridge to an adjoining property if theirs is wired. You don't want to be setting off other alarms.
  • Some local authorities don't like wireless ones

Wired Interlinked


  • Wired are less likely to suffer a ‘technical glitch’
  • Cheaper to buy
  • Wider range available


  • Will cost more in terms of labour
  • Lots of messing around with lifting carpets and floorboards

To read more articles like this one, please visit our Home Alarms page.

Aico EI141RC