HVAC Efficiency/energy monitoring


Active Member
This may be the wrong forum, though it could be considered tangentially related to HA....

I would like a way to continuously log energy usage for my entire house. I do this today with my water meter, but have not found a DIY accessible power meter. Any ideas?

Also, anyone have some good tips to improving energy efficiency of HVAC system ? It's your basic 3200sqft two zone SER 10 electric A/C system. I have some of my own logic controlling temperature settings based on the outside temp and our presence in each zone, but last month or power bill was still over 500 bucks. I can get an interest free loan to make improvements, so I am open to going as far as a 5-7 year ROI.
I like the energy detective product as well. There have been several posts about it on this forum, and positive reviews on other forums (do a search here and at HomeSeer.)

They are planning to release a version that has a computer interface for logging and analysis, but they have been promising this for a while. I think they would sell a bunch of these if they would get the thing finished.
Not only does it need a computer interface, but it needs to have a programatic way of accessing that computer data so interfaces can be written... These are great links though!

Now maybe I can catch up with my buddy at www.BWired.nl =)

Just thought I'd add my experience with the "TED" monitor. Been using mine since last November with good results. Just checked in a couple of days ago with "support" there and they said an announcement was due in 4-6 weeks on new stuff. By the way just out of curiosity I did peer inside the unit and the port on the side is already connected to an RS-232 interface chip, plus what appears to be a transistor or similar for a switched output. So with the the right interfacing cable/software, it looks like some capabliltiy is already there.

The only caveat here is that the TED, at least my unit, transmits its data at a 1hz rate very near X-10 and Insteon signals on the powerline. Lots of interference for me! In my case I had to add a pair of chokes ( out of a couple of futzed X-10 appliance modules ) to isolate the TED's signals from the rest of the AC lines. Since gone Z-Wave, so I can mount it pretty much anywhere again.

I called brand electronics and they hooked me up with a data logger that also has a real-time interface. I'll write up a review once I get to the bottom of things.
It's a "custom" whole house "one meter" unit (no model number). There are two boxes, a data sampler and a data logger. You put the data sampler near where the power comes into your house, it has two (or more) amp meter loops and a voltage tap. The data logger sends amperage and voltage data in real time to the data logger, which integrates the data over configurable intervals to get kwh. It has enough memory to store 120,000 intervals. The data logger also has a rs232 port and comes with windows software that allows you to download data from the logger, or monitor it in real time. ~$400 shipped. The key for me is that I can have 1 minute intervals and that I can see the data in real-time if I like.
I've been using the OneMeter for over a year for monitoring whole house usage. Works great. I'm doing the backend polling and analysis through scripting and putting all data into tables in mysql.

The methodology I'm using is to poll each 5 minutes, get the power used, and then reset the realtime data. I originally was using the built in data logger and polling at longer intervals, but found it easier to script and collect and reset.

Attached a few snippets from my test pages; I've done a similar layout to bwired.


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This is very neat. For the several of you using these devices, how have you saved electricity and what kind of $$$ has that translated into for you.
I'm very interested in doing this for the new house I'm having built. The electric is just going in now and the sheetrock is a way off yet. The One Meter sounds like a good solution.

I've looked at the documentation on their web site but I can't quite figure out from reading it *exactly* how the current probe connects (presumably) to the breaker panel. Can one of you who is using this already provide a bit more details? If I can do a neater installation due to the fact that the sheetrock is not yet in I would like to jump on this right away.

I'm also debating installing two data collectors - one for the entire house and one just for the dedicated circuit for my computer equipment. I've always wondered how much power my PCs really use and this would be a great way to know. Any thoughts?

-- Dave
(I would also do this for your water and gas meter as well)

Buy a system and give it to your electrician to install. These things typically have a current sensor (which is just a loop/donut your major current carrying line goes through) and a voltage tap. You will need a cat5 from where ever your computer/display is to the location the current and voltage sensor are. On my house this is outside at the main breaker box. When I install mine I will takes some pics and post.