Looking to upgrade your home to a "Smart House" without tearing everything out and starting from scratch?

Considering all the smart home products that have appeared in the last couple of years, it’s getting hard to resist the temptation to strip one’s house down to a wooden frame and start all over. Like the Six Million Dollar Man, we can rebuild it. We have the technology. We can make it better...more efficient...more connected than before.

The smart-home market often fuels this impulse by offering products that replace the “dumb” appliances and infrastructure of existing buildings, without regard for the decades-long life cycles and sunk costs that homeowners have already invested.

Luckily, more and more products are taking the “retrofit” approach: designs that piggyback on a home’s existing infrastructure to connect it to the Internet of Things, inexpensively and without the use of power tools.

Heating and Cooling

Air Conditioners

Price Ranges: $108 - $159
How they work: Infrared Hubs

Smart thermostats have been the poster child for the IoT ever since Nest hit it big, but they only work for homes that have central control over heating and cooling. Sensibo, Ambi Climate and Tado Cooling are three products for automating any standalone AC unit that can be operated with an infrared remote control.

Ambi and Tado can control multiple units in a single room, while Sensibo places a sensor on each AC unit in the home and ties them to a central hub with Zigbee.

All three systems use predictive algorithms, presence sensors, weather data, and other sources to optimize the indoor climate while minimizing energy consumption.




Meet Sensibo. a device that turns any a/c smart, and saves 40% on its energy usage.

Price: $159


Ambi Climate


Ambi Climate uses predictive climate control by monitoring the temperature and environment both inside and outside to minimize energy use and maximize human comfort.

Price: $129 (Pre-order)


Tado Cooling


Cooling turns any AC unit into a smart device: Auto-off, precooling, indoor presence detection and single room control.

Price: $110 (Pre-order)

See also:
For homes with central heating and cooling, Ecovent and Keen Vent are two products that allow airflow into rooms and zones to be controlled automatically based on presets and presence, improving the efficiency and effectiveness of indoor climate control.


Deadbolt Locks

Price: $89
How it works: Unknown (patented) attachment mechanism



Sesame is the first smart lock we’ve seen that doesn’t require removing or replacing a single piece of your deadbolt. It simply fits over the existing thumbturn on the inside of the door, and rotates back and forth in response to commands from a mobile app or a secret knock (when an authorized smartphone is within Bluetooth pairing range). Actually, the inventors say Sesame isn’t really a “smart lock” at all—it’s a robot that locks and unlocks the door for you.

Price: $89 (Preorder)

See also:

Postscapes’ Smart Door Locks roundup collects products that replace or augment mechanical locks to enable proximity-based and remote access. Our Smart Garage Door Openers roundup collects products that wire into an existing garage door opener to allow smartphone control and proximity access.

Safety: Fire, Smoke, & Carbon Monoxide Alarms

Price Range: $40-$99
How they work: Batteries and Audio



This little gadget takes a familiar 9-volt form, and is designed specifically for smoke alarms. Whereas a standalone product like Nest Protect or Point would replace your entire smoke alarm, Roost only replaces the battery. The swappable lithium cell lasts for up to five years, and embedded electronics keep it connected over Wi-Fi so it can push notifications when the alarm goes off and remind you—quietly!—when the charge is running low.

Price: $40 (Preorder)



Leeo is basically a digital ear on constant alert for the squeal of a smoke, fire or carbon monoxide alarm. It plugs into a nearby outlet and connects to Wi-Fi to push alert to a homeowner’s mobile device. Leeo also includes temperature and humidity sensors, and it doubles as a nightlight.

Price: $99

Windows & Lighting

Price Range: $40-$75How they work: Actuators, magnets and bulb sockets



A truly elegant retrofit, Rise is a completely self-contained solution for blinds that raise and lower on a looped chain. It can raise and lower the blinds on demand, on a schedule, or in response to light levels. The outward-facing side is a solar cell so the battery charges itself, and stores plenty of extra juice for cloudy days.

Price: $75 - N/A


Ember Socket

Smart lightbulbs are invariably made with LEDs, which have a super-long lifecycle that justifies their high price. But most of us are still in the process of running through our incandescent and compact fluorescent bulbs, so Ember puts the smarts on a screw-in socket attachment instead.

Price: $49 (Preorder)


Like the Sesame smart lock, Switchmate takes an overlaying attachment approach to a retrofit. The battery-operated device fits over any toggle or rocker light switch by clinging magnetically to the wall plate screws. The switch can still be operated manually at the touch of a button, or through a smartphone app -- Switchmate’s moving parts turn it on and off mechanically.

Price: $60 (Preorder)

Electrical / Power

Price Range: $40-$99
How they work: Breaker panels and electrical outlets


Neurio’s sensor connects to a home’s breaker panel, where it can monitor all of the electricity flowing in and out the house. Cloud algorithms detect the signatures of different appliances and other power draws, which enables smart notifications like “You left the oven on” or “You ran the washing machine, but forgot to dry your clothes”. It can then combine with automation platforms and other smart gadgets to trigger smart behaviors (like using a smart outlet to cut the power to the oven).

Price: $249

Smart Outlets

Attaching to existing power outlets to collect electricity consumption data, and enable automated and remote control of appliances.

Price: Ranges - See Smart Outlet Roundup


Price Range: $40-$99
How they work: Actuators, sensors


Water Hero

Like several other retrofits featured here, Water Hero is really a small robot with a single job to do: prevent disastrous flooding. One piece is a leak detector that straps to the outside of a home’s flowmeter, where the main water supply enters the house. If it detects a burst pipe or other unusual flow, the second piece springs into action with an actuator that cranks the home’s shut-off valve to the off position. It alerts homeowners over Wi-Fi, and can also diagnose slow leaks.

Price: $149 (Preorder)


HydroPoint 360

Designed by an irrigation control company, HydroPoint 360 attaches to the cold water line under a kitchen sink. It detects vibrations in the plumbing that correspond to water use throughout the home, building up a complete picture of consumption habits.

: N/A

Additional resources


Connected Car Devices

Capture your cars computer sensor data using your vehicles on-board diagnostic port.

Price: Ranges - See Roundup


Smart Bike Locks

Social Sharing - Allow your bike to be used by friends, family. Analytics -- Log your latest ride stats, total miles covered during the year and receive crash alerts -- Severe crashes can be detected using accelerometers and have alerts sent to family members.

: Ranges - See Roundup

Smart Shoes

Products: Boogio, Stridalyzer, Runscribe

These three products outfit any pair of shoes with sensors that collect information about balance, force of impact, and the way feet flex with every step.

: $129 - $189

Sports Equipment

Zepp is a small motion sensor that attaches to the handle of a baseball bat or tennis racket, or clips to a golf glove. It captures data from each swing and sends it to a mobile device over Bluetooth, so users can see 3D recreations of their technique, analyze swing speed and other data, and compare themselves with professional players.

: $149

Retrofits tend to be cheaper and easier to install than standalone replacement products, which make them more sustainable, and appealing as introductory products to homeowners unfamiliar with the IoT. They’re also great for renters, who may not be able to mess with things like wiring and plumbing without the landlord’s approval.

Deciding what counts as an IoT retrofit is not an exact science. In this roundup, we’ve chosen to focus on products that add connectivity and computational intelligence to something you already have in your home, but that can’t stand alone as a complete functional product without that pre-existing object. That means we didn't include multi-purpose sensors, even though they can provide a range of utility around the home (check out our separate roundup for examples).

More to come as this category develops.

Looking to develop your own Connected Home Product?