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Any raters using any electrical energy monitoring systems as part of their energy audit? There is TED and new systems that directly interact with Smartmeters.

I have projects that have high utiltiy bills. BPI/HERS/Energypro audit seems focused on heat/air, WH and envelope. Any experience and opinions are appreciated.

Comments

  • I'm not really a rater, but I am frequently investigating high utility bills, usually electric bills. In those situations, the question is "where did all the electricity go?" and in most cases, the answer is difficult to determine without circuit-level monitoring. Electric loads are often inconsistent as equipment cycles on and off, intermittent problems appear and disappear, etc. Unless you have a way to capture the data, it is hard to be sure. Meter readings don't usually help much.

    On an inspection this morning, the owner (absentee, unoccupied vacation house) complained that his bill was more than twice the usual amount for the time of year. I could not get the heat pump to run, but got the system to heat in emergency mode using the heat strips. Based on that, I told him to have his system checked. I am 95% confident that's his problem, but how do I know the neighbor kids haven't been using his hot tub on the deck every night?

    On another inspection last week, I found an electric heater running full-blast in a well house even though it has not been freezing. Pretty sure that's the problem, but who turned it on and when? I couldn't find any other loads to explain the issue at the time, but that doesn't mean there aren't other problems.

    In another situation I had to visit a house three or four times--the last time at 9 PM--before I found that there was a 3500-watt baseboard heater on a faulty thermostat. It looked like it was off but would actually come on during the coldest periods. That never happened during daytime visits.

    Sure would be easier to solve these issues with a monitor on all of the loads in the panel, reporting wirelessly. Of course, how to you fit that into your business model if you're supposed to visit the house only once?
  • TED and a handful of other systems support "submetering" of AC and heat pumps, which makes correlation with envelope and hvac improvements much more useful. There are even ways to submeter gas for those who are motivated to do so, but as with everything else, it comes down to cost and effort.

    I bought a TED system with an extra set of CT's for my HVAC circuit. But I sold it because the firmware was poorly designed and implemented. I now use a Brultech ECM-1240 with Check-It web portal to monitor several of my large electric loads. It costs under $200 for the hardware and $99/year for the web portal service.

    The least expensive way to monitor an AC or heat pump for clients, and what I recommend, is a surplus utility meter. These can easily be installed by the electrician during construction, and in many cases, can easily be retrofit, depending on location of sub-panel, etc.). Analog meters are available through Vision Metering for $15 plus shipping and base-socket. But the homeowner must be willing to read the meter twice yearly. I have several clients who have opted to do that. I send them a reminder (something I need to automate).

    I am hopeful that the new emphasis on 'smart meting' will eventually lead to less expensive sub-metering solutions, but access to billing data through the utilities is problematic (privacy concerns, as well as utility desire to control vertical markets related to smart meter data).

    I will soon be developing an all-electric net zero community and one of the key features will be sub-metering of HVAC and DHW on all homes. One evolving technology I've been following for more than two decades is signature analysis (pattern recognition) by which a specialized signal processing chip monitors several parameters on the main electric line (phase shift, current, harmonics, etc). After initial training, it can separate various large sub-loads. This would greatly reduce the installation costs associated with current methods for sub-metering. Fraunhofer CSE is currently looking at this (http://vimeo.com/18472128).

    As you can tell, low cost energy monitoring is one of my passions, but I'm less interested in whole-house energy monitoring since it reveals so little about the sources of consumption.
  • David, why do you say the client has to read the sub-meter twice yearly? Once for heating and once for cooling?

    Thanks for the tip on the Brultech stuff. That's much more affordable than some of the others I've seen.
  • Correct. It depends on what you're trying to accomplish, but if we want to do a better job estimating heating and cooling energy and associated savings from improvement measures, we need to monitor these separately.

    I have one client who had his plumber install a surplus gas meter on his furnace. That's a bit overkill because regression analysis provides reasonable accuracy for extracting heating energy from monthly gas bills if you have at least a couple of years of consistent billing history.
  • Just have them take pictures. Homeowners seem to find that easier, and I like having the record. http://bit.ly/meterpictures As you can see, I leave notes right on the picture.

    I recognize some meters have analog dials. Here we have the crazy clock hand thingy's.

    Either way I would prefer to see the meter, and the picture time stamp, than count on a homeowners read.

    Anyplace I can increase my confidence in a number with little to no extra cost I try to.