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Monitoring of HVAC systems

Russgs | Posted in General Questions on

I would like to install some extra meters and monitoring points on my HVAC system for a new home build. I would like to be able to collect and graph all the data points like gas consumption, electricity, boiler water supply and return temperatures, fan coil run times and various temperatures through the home.
Essentially I am looking for a residential version of a Building Automation System (Honeywell, Siemens, Johnson Controls etc) 
Can anyone provide me with some ideas of where to go to get the software and interface modules and sensors I require?
Looking to bring back data points to a central controller and output the data to a computer for analysis. I don’t really need to “control” anything.
I am just a nerd that wants to collect as much data on how my systems are operating as I can.

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  1. bfw577 | | #1

    I do exactly what your looking to do. I monitor my mini splits using an Efergy electrical monitor and use an Acurite weather hub for temp/humidity. Acurite has a ton of various sensors with remote temp probes. All the data is acessed through an ap on my phone and can be exported. I have 6 space temp/humidity sensors throughout the house and monitor my mini split return and supply temps as well.

    Here are some screenshots of my data as well as the acurite sensor I use.

  2. Expert Member
    NICK KEENAN | | #2

    What you're talking about isn't simple. It's possible, it's just not easy.

    To the extent you system has the sensors already, they're not going to be easily accessible. Residential HVAC systems don't generally have data ports and if they do it's going to be proprietary to your brand. Where there aren't already sensors you will have to figure out how to retrofit them. There are a variety of techniques, but they will be specific to your device. For existing sensors you will have to either tap into it somehow or retrofit another one.

    For residential systems the interface to the world is the thermostat, which is a crude interface: on/off switches that call for the heat, cooling or fan to come on. There are smart thermostats that will log this for you, but it's not the level of detail you want.

    Once you have the raw information, you have to figure out how to log it and then display and manipulate it. This requires some sort of logging device with internet access.

  3. bfw577 | | #3

    The runtimes for anything electrical can easily be recorded with the Efergy. In fact before I installed my 2 mini splits I knew my exact heat loss at various outdoor temps using the efergy. I monitored my oil furnace electricity runtime and was easily able to get an exact heat loss number.

    My oil furnace is 80k btu/hr. I just looked at how long it ran each hour and you have a crazy accurate heat loss number. Actually I ran my oil furnace as I had company staying over Fri night. Here is the runtime graph of it cycling on off Fri night as an example.

  4. Russgs | | #4

    Thanks for the replies.
    Since I'll have a fully modulating condensing boiler I will need to measure more than run times. I will have to use strap on temperature sensors to measure the supply and return temperatures and with the GPM from the pump curve I'd be able to calculate the BTUh this way.
    Problem is finding something to data log the temperatures. I know Onset sells a variety of loggers I could use but I was hoping for something a bit more sophisticated where I could pull in all the data I want into one place.
    Thanks again .

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