is it expensive
One last post, specifically on budgeting...
Like most DIY areas, project cost can vary widely. Most electrical devices, including home automation, fall into good/better/best categories with a very wide difference in cost. That's true for everything from a lightbulb to the sound system.
Some people like to plan a budget in advance, some just consider each individual device at the time that they want to purchase it.
I myself am quadriparetic, use a wheelchair and have limited hand function. So I only automate things that have an immediate practical purpose. And because my budget is limited, I won't necessarily do all the switches in one room. I might do just one in order to give myself voice control over those lights and leave regular switches for my able-bodied housemates to use.
Other people want to do the full Jetson House, even if it's just one room at a time, and automate just about everything that they can.
One option: a per room budget
My budget is based on spending about £200 to £400 pounds per room. My minimum spend from a practical standpoint is based on the following:
two repeating devices per room. (Z wave can only repeat for Z wave and zigbee can only repeat for zigbee and I like to use both. Almost all mains powered devices using these two protocols can act as a repeater, typically light switches, in wall outlets, Micro devices that go inside the walls, plug-in sensors, and plug-in pocket sockets.)
One sensor per room
One voice control device per room (the Echo Dot is £45)
One a/v Control device per room that has a television (I use Logitech Harmony, £99)
And then based on the typical occupancy of the room, one additional convenience device per person, which might be a handheld button controller or another sensor or a tablet dashboard. Not necessarily the same device for each person.
In the U.K., the sensors and repeating devices typically cost between 30 and 50 pounds per device. There are sometimes deals to be had and sometimes less expensive Chinese made versions. but I can meet my budget with this design.
Add ons that I count separately from the per room budget
Devices to be purchased separately from the per room budget are door locks, thermostats, garage door controllers, fire safety systems, and sprinkler systems. These are the individual pieces that some people will want and some people won't, where an individual device might be £500.
I also don't automate every room in my house. I spend most of my life in one of two rooms: my bedroom and the living room, and some time in the kitchen, one bathroom, and the corridor between them.
One of my housemates has some automation in his room, but not as much as mine. My other housemate doesn't have any automation in his room. We did automate the living room, where I watch television, but did very little in the large family room. That room isn't wheelchair accessible, anyway, as it has a step.
Some people start by just automating their home theater room. Or their kitchen. There's a lot of variation, but I would start by looking at the rooms where you spend the most time.
Again, this is just what works for me and what I typically suggest as a starting point for someone in a similar situation to mine. If you can't use your hands, voice control of the television is much more important then for an able-bodied person. At the same time, I'm not as concerned about aesthetics as someone else might be, and I don't care if all the switches in a room don't match.
There are other people who couldn't imagine not automating the lights in all the bedrooms. Or who begin by automating the children's rooms.
thinking about replacements
When I very first began, I set a limit of £1200 ($1500) for my phase 1, with the idea that I would just start experimenting with home automation but I would be OK if I had to replace the entire investment into years. I wanted to see what would work for me, but I knew the industry was changing very quickly at that time (this was three years ago) and I didn't want to have to worry too much about "future proofing."
then my phase 2 goal was based on that per room budget, with a whole house maximum of £4,000 ($5,000).
About 18 months in I somewhat changed the way I looked at the budget. I realized that there would always be technology changes, and that my own needs might change as well. I still stuck to the idea of 300 to 400 pounds per room, but I decided that that particular investment only needed to last for three years. So it was something like a mobile phone where what I mostly look at is the per month cost with an expected replacement cycle.
Looked at that way, after my initial investment i'm putting aside about £100 A month to cover eventual replacements. So around £3 A day to get all of the automation that fits my budget with a three year replacement cycle to keep me up-to-date on new technology.
So is that expensive? Well, in my case it's considerably less expensive than paying personal aides to do things like change the television channels for me. It's definitely not inexpensive, and it is more than just my mobile phone, but it's not terrible.
And it certainly much less than the expensive home automation systems cost. A good system from control 4 typically runs about 10% of the cost of the home plus an ongoing annual cost. Which is many times more than my budget.
I do think you should consider the cost of replacement when you look at what you're spending. There are many people on these forums who spend 150 pounds a month or more just on devices they haven't quite come up with projects for yet. Which again, is fine if you have the money and it's an interesting hobby for you. Just don't spend that kind of money and expect these devices to last for 20 years. Or even 10. Networked devices typically have a 1 to 2 year warranty for the good and better categories, and a five year warranty for the "best" group. And again, there will be updates you want to make just because newer technology is now available.
I should also say that there are people who set themselves a goal of spending absolutely as little money as possible, and do a lot with devices they build themselves and various kinds of maker skills. Again, there's a lot of variation.
So again, different people will approach this differently. My own advice would be to pick a per room number for your initial investment and give yourself 12 to 18 months to get there. Start small and learn your own preferences for how you want automation to work in your life. Be willing to toss out everything from your phase 1 and start over if necessary.
Once you've completed that first phase, reevaluate, and again my suggestion would be to come up with a per month budget with a three year replacement schedule. You might spend four months of budget all in one go, but you should be aware that you've done so. If your per month budget is £8, that's fine, as long as you know what it is.
So if you treat home automation like home Internet or a heating system I think you can plan for it, budget, and spend the amount you think is reasonable to spend.
If you don't have a budget and you don't plan for replacements and you don't have a sense of how you're going to scope your projects, then you can easily end up spending thousands of pounds and regretting a great deal afterwards.