Add-A-Wire Accessory, Briidea Common Wire Kit for All 24VAC Thermostats (4 to 5 wires), White

I am an air-conditioning contractor, and have used products like this for the past 15 years. Even veteran contractors often do not know this product exists and it is a lifesaver. Due to the increase in use of Wi-Fi thermostats, which require a common, more people are using similar products. This is because Wi-Fi thermostats require a common . If a common ids required, you must have a minimum of five wires and many homes were wired with four wires if they had single stage heat abd mercury thermostats. This is a common issue with older hones. Another issue is that Low-voltage wiring is very fine and it is hard copper, not stranded. So, age can allow for deterioration and breakage causing problems.Since thermostat wires can be very difficult to pull, depending on if the wire is nailed inside the trusses, inside the walls, in a multi level home or condo, this product can also provide a replacement for a broken wire for a standard stat.This inexpensive product allows us to forgo running a new thermostat wire, at several hundred dollars expense to the customer. We can provide a replacement wire for a daily wine when pulling a new wire is difficult or cost prohibitive, or provide the common needed when needed for a wifi stat when only 4 wires exist. However, it is really designed for a professional to use not for the homeowner. It seems easy enough but truthfully a homeowner risks shorting tge unit or injuring themselves if they don't have the knowledge BBC a s it gets wired inside the air handler/furnace, as well as at the thermostat.

The product did the job, and it is a good solution for getting a difficult to access thermostat run with 4+ wires up to the 5+ required to correctly run something like a nest with basic heating and cooling. If you have any less in the wall, it's probably just not worth it for a standard HVAC system. Even with 4 wires and two of these kits, you can only get to 6 wire equivalent, which doesn't run quite everything you would find in a typical house (pick only one of 2 stage heat, 2 stage cooling, and humidifier). If it's even moderately accessible, just buy yourself a nice flex drill and pull in a new 7/8 wire thermostat bundle.Installation was a hassle on my furnace, though. First, the included wires are really short, to the point that I had to extend them just to reach a surface for mounting. Secondly, the extra wires would not fit on the terminal screws along with with the original wires, so I had to crimp spade connectors to each pair. Third, the expectation is to use a wire nut to connect the diode to the blue wire. A bunch of thermostats, mine included, use solid/stiff wire and small holes in the wall. The wire nut did not hold well under that stress, so you may need to either make a larger hole in the wall, or replace the joint with something more sturdy, like a tight mechanical twist and solder.Expect to make minor adjustments to get things working. This type of product isn't suitable for someone without a selection of basic electrical tools (drill, fasteners, shrink wrap, strippers, cutters, crimpers, spare wire, terminal connectors, etc.) and comfort working with them, but I would recommend it otherwise.

The instructions are not great but it works.

I went from a four wire thermostat R (24VAC), W (Heat), Y (AC), G (Fan) to one that required a common wire, C to power the new thermostat. Not wanting to rip open the walls to thread in a new wire I tried the add-a-wire and it solved my problem. Installation is straight forward only requiring a screw driver.

Works as intended. Purchased a new Thermostat with a wifi connection that required the C wire that my house wasn't equiped with when it was built. My HVAC tech was able to use it quickly and get everything up and running.

Works great for my nest thermostat.Easy to install.My unit didn’t have a c-wire and this works great as a substitute. Beats running new wire and rewiring entire set up.It does require you to wire to control panel.

Installation was very easy. I glad I did not buy 2-3x more expensive adapter. Now, with new WiFi thermostat I can control house temperature very easy.

Gets the job done. In one of those people that doesn’t really read instructions unless it's completely necessary. Despite that fact, setup was a breeze & it fits behind the thermostat flush. So no complaints.