New user with new-old house

Hi All,

I’m new to SmartThings and very excited to get going. I’ve been browsing the forums for a few months and when I saw that the V2 was coming soon I decided to wait. Now that I’ve pre-ordered it I’m really getting started in my planning. I’ve recently purchased a new home that is a bit older, built in 1949, and have some concerns about it’s wiring and compatibility with switches/outlets. I have an electrician coming by next week to take a look at what she can do, but one of my biggest concerns is the physical size of the Z-wave devices.

I’ve read on a couple posts that switches/outlets are larger than standard, and after removing the face plates in the house I can see that it’s already a tight fit in the existing boxes. I’ve decided to get the GE switches/outlets from Lowes but for the life of me can’t find any information on their physical dimensions. I’d prefer not to have to buy one simply to find out that it doesn’t fit without having to install all new boxes, and increasing the cost to implement. Any chance someone knows how big they are?


Here is the dimension for the Older GE. You can check out other switches by clicking on spec.

"IT’S BIGGER ON THE INSIDE. " (Sorry, couldn’t resist. :wink:)

The point however is that while zwave antennas are pretty big, A light switch device is still designed to fit into a one-gang switch box. There’s usually enough room to just swap it out for the existing switch unless for some reason it was a really really narrow switch box which would be unusual.

So if the switchbox is of standard dimensions, a typical Z wave or zigbee light switch will fit in it.


The size issue usually comes when you try to fit two different antennas into a standard single gang space. This is why a zwave-controlled outlet with two places to plug things in typically only has zwave control for one of those two and the other is a standard nonnetworked receptacle. But the outside dimensions will be exactly the same as the outlet that’s being replaced.

There is a new zwave standard, Z wave plus, which does have somewhat smaller antennas and we are starting to see more devices coming out using zwave plus. So we may start to see more options over the next year or so for outlets.

But the outer dimensions of all the devices are still the same standard size.

As Ray says read the dimensions carefully before buying anything but I don’t think you’ll run into that particular problem.


The most common issue people run into with US houses built between 1940 and 2000 is that they often do not have a neutral wire at the light switch. Most networked switches will need a neutral because they have to be powered on even when they act like they’re off, so that they can still hear the next “on” command.

However, there will be a neutral somewhere it just may not be at the switchbox itself. For example, almost all outlets will have a neutral. And if there isn’t a neutral at the light switch, there should be one at the light fixture.

So for older US houses an electrician can usually “fish up” a neutral from somewhere else in the wall. That allows the Z wave or zigbee switch to be installed.


The other issue you run into is if you want to keep your existing switch hardware, but put a micro relay inside the switchbox to give it network capability. Basically turning a dumb switch into a smart switch. These devices do still require a neutral for power. But they also have to physically fit inside the switchbox. This is where the question of narrow versus deep comes in. A standard switch box will typically be deep enough to easily fit the micro inside. But there are some narrow switch boxes Which are to code but may not have enough room for the micro.

So if you think you will want to use micro relays with the existing switch hardware, then you need to have the electrician check each switch box to make sure there will be room.

But if you just want to swap out a smart switch for a dumb switch, the outer dimensions should usually be the same. :sunglasses:


I have a house that was built in the 40s. Lots of plaster! The boxes were generally ‘standard’ size, which made for a right fit for z-wave devices, but in every case I could fit them in.

In some cases I had to ‘chip’ away plaster that ‘leaked’ into the box from the front when it was first built, but this wasn’t too big of a deal.

In other cases there were “bundled” cables in the back of the box which causes a tight fit, but again I was always able to get the devices in.

My biggest issue was the Neutral. Old house… not every box has a neutral in the back. I’ve been very lucky for the most part in that I’ve always found a way to get it to work… either there were tied off neutrals in the back of the box, or I was able to use one of the older Dimmers which doesn’t require a neutral, or I was able to fish a neutral line down from the attic. But definitely scout out neutral lines in a older home to find out if you have 'em.


Thanks for the info everyone! I will definitely be checking those dimensions against my measurements when I get back home today. I do have plenty of plaster to deal with so I’ll see if that is creating a problem anywhere.

Having the neutral wire is my second concern. Worst case scenario if I can’t install the smart switch I’ll invest in some smart bulbs. I’m already planning on grabbing a Hue starter kit to use for the living room lights to set the proper mood (movies, video games, quiet dinner on the couch), so getting a handful of the Lux bulbs seems to be a fairly functional work around to the switches. Not perfect, but I think it will still achieve what I’m going for.

One other thing to consider re: outlets:

When I first got started I got a number of the Z-wave outlets. If I had to start over again, I go with a lot more of the appliance plugs rather than physical outlets… especially in bed rooms. My wife and daughter like to re-arrange bedrooms occasionally and when this happens it means thinks like accent lights, radios, chargers, etc. all move to new outlets. And that means having to changes scheduling in my various smart apps.

Instead I should have just gotten the plug in modules. Then when the light or radio or whatever moves, the module moves with it to the new ‘dumb’ outlet. No changes in smart apps or remotes needed.


I like the GE Links as a white light only bulb to use with the Hue bridge. List $15, but typically $12 each on sale, so excellent value, and I like the color temperature better than the Hue lux. Check Home Depot, target, and Amazon for sales, they all run sales regularly.

You can also use the GE links without a huge bridge, they are one of the bulbs that can connect directly to the smart things hub.

Item descriptions will say that it needs the wink hub or the link bridge: it doesn’t, just the bulb and SmartThings is enough. :sunglasses: :bulb:

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Hey @Aelstrom, it’s like we’re twins or something.
Modular Installation to Old House

Once HubV2 is out I’m going to look into the Neutral Wire situation but as many people have said, Zwave LED Bulbs are pretty much the best option. I like what @chrisb said as well - using plugs rather than the outlets for a more modular approach.

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Plus… a lot of Z-Wave plug-in modules (dimmers, especially) have both a smart and dumb outlet on them and won’t even block two wall outlets, and can be used on an extension cord, etc., etc…

You lose the “built-in” look, but gain a lot.

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Agreed. I even found some cheap on/off ones of eBay a while back that were without the ground plug, with works great with things like radios or device chargers which don’t have a ground and should be used on dimmers.

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You could always get [these] 1 cheap bulbs. They work with ST!

Thanks for all the feedback everyone. I’ll definitely be able to create a solution with these options, and while waiting for word from my electrician I’ll keep on researching and planning.

Remember, Bulbs will NOT extend your network. Bulbs only repeat Bulb communication and will ignore all other devices causing problems.

I strongly recommend buying two or more plug in devices that will act as ZigBee repeaters. The Smartthings switch outlet device will do that for you.

If all you are using is bulbs, then you are good. I found the cheapest and most robust is the GE Link bulbs at $12.00 each from right now. The Cree Connected are nicer looking but are finicky and do not extend your lighting mesh network (in my experience), the GE bulbs do.

It’s a bit more complicated than that.

Zwave lightbulbs, like the Aeon or Linear, will act as zwave repeaters.

Zigbee lightbulbs can use one of two different protocols. Bulbs like the Phillips Hues which use the zigbee light link protocol (ZLL) will only repeat for other ZLL Devices.

Zigbee light bulbs which use the zigbee home automation profile (ZHA) will repeat for other ZHA devices, including non-lightbulbs, but will not repeat for the ZLL bulbs.

And a few zigbee lightbulbs use their own proprietary encoding over zig be standard, and won’t repeat for anything except their own brand. I believe this includes the WeMo lightbulbs.

So all the zigbee and Zwave lightbulbs repeat for their own brand.

Z wave light bulbs act as general Zwave repeaters.

Zigbee lightbulbs may repeat only for their own brand, or only for their own protocol (ZLL or ZHA.) If they are ZHA profile, they may repeat for other Zigbee devices also using the ZHA profile, including non-lightbulbs.

For example, Phillips hue bulbs will only repeat for other ZLL bulbs Associated with the same bridge. Osram Lightify bulbs, on the other hand, will act as general zigbee repeaters for devices using the ZHA profile.

More in the following topic:

Target has the GE bulbs on for $11.24 right now.


Finally had the electrician come through. I won’t be doing any smart switches, while there does appear to be a neutral wire, it’s being used as the traveler for the 3 way switches, which are the majority of what I have. I’ll be relying on the bulbs themselves, and will be taking the advice to build a more modular system with the outlets.

One good thing that came up is after taking the existing thermostat plate off the house has all the necessary wires to install pretty much any new thermostat, so I’ll begin researching that next.

In terms of the actual mesh network, the location the hub will be in is almost dead center in the house, no further than 25 feet to an outside wall. I’m hoping that the walls won’t present too much interference, but I’ll have at least one device that can act as a repeater in each room. I suppose the only way to know for sure is to get things set up, and be ready to make some tweaks on where the devices are located.

Thanks for all the advice everyone!

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