I’ve been using HA for a while; having my home just “do things” for me without asking is fantastic. My lights turn on to exactly the levels I want when I enter a room, my grass and my plants get watered automatically, heating and cooling happens only when it needs to. There are lots of benefits. Plus, it’s just a fun hobby.
One thing I didn’t expect, though, is all the interesting things you can learn when you have sensors monitoring different aspects of you home or the environment.
- I can always tell when someone is playing games or streaming video (provided they’re transcoding the video) from one of my servers. There’s a very significant spike in temperature in my server room, not to mention the increased power draw.
- I have mmWave sensors in an out-building that randomly trigger at night, even though there’s nobody there. Mice, maybe?
- Outdoor temperatures always go up when it’s raining. It’s always felt this way, but now it’s confirmed.
- My electrical system always drops in voltage around 8AM. Power usage in my house remains constant, so maybe more demand on the grid when people are getting ready for work?
- I have a few different animals that like to visit my property. They set off my motion sensors, and my cameras catch them on video. Sometimes I give them names.
- A single person is enough to raise the temperature in an enclosed room. Spikes in temperature and humidity correspond with motion sensors being triggered.
- Watering a lawn takes a lot more water than you might expect. I didn’t realize just how much until I saw exactly how many gallons I was using. Fortunately, I irrigate with stored rain water, but it would make me think twice about wasting city water to maintain a lawn.
- Traditional tank-style water heaters waste a lot of heat. My utility closet with my water heater is always several degrees hotter than the surrounding space.
What have you discovered as a result of your home automation? While the things I mentioned might not be particular useful, they’re definitely interesting, at least to me.
My old furnace was hilariously oversized for the house.
One of the nifty things about smart thermostats like Ecobees is that you can pull usage data from their web portal. I grabbed a CSV file covering a cold snap last year that reached a 100-year record low, and using Excel I summed up the total heat output while we were at that low.
The furnace was only running 50% of the time, even when it was with a couple degrees of as cold as it’s ever been where I live.
Needless to say, when I got a new system installed I made sure it was more properly sized, and given that I had a convenient empirical measurement of exactly how many btus I actually needed in the worst case as scenario, that was easily done.
Not sure if you got this idea from Technology Connections but he recently didn a video using this exact premise.
I checked HA and found that A) my furnace fan is likely dying as the furnace overheats and power cycles frequently and B) despite the overheating, or furnace has only run at most 25% of the day during the coldest temps we’ve gotten this winter (which has been mild and only down into the low 30s). I think if/when we replace the furnace we can safely cut the BTU rating down while still maintaining our desired temperature.
I’d been planning for a new HVAC system for a while when that video came out, and it gave me the idea to cross-check the thermostat data with the Manual J calc I’d already done. They were in general agreement, though the Manual J block load was more conservative than empirical data for a design day.
In your case, since you don’t have data from a healthy system on a representative heating design day, I’d suggest using a web tool like CoolCalc to simply calculate an approximate Manual J total heating and cooling load, and use that to guide your choices.
Having an oversized furnace really isn’t a bad thing, and only having it run half the time sounds like a good thing to me.
It wears out the furnace doing short burts and the house doesn’t get heated evenly. I had the original furnace from 1968. When I upgraded everything with insolation and better windows, I went from a 80,000 BTU on/off furnace to a 40,000 but modular furnace. No more sweating after 10min and then cold. Just evenly bring up the temp over a longer time. https://youtu.be/DTsQjiPlksA
That technology connections video is great. It’s crazy how oversized heating systems are, especially when it costs us so much money.
A little headroom ain’t bad, but it had three times the required heating capacity for my area’s “design day” low, which meant that for most of the winter it was kicking on for maybe 5-10 minutes per hour and then leaving massive cold spots in the house, because the thermostat was smack in the middle and all the walls were bleeding heat.
My new heat pump is just about 2x the design day heat requirement, but that also means it’s got capacity to handle extreme lows without resorting to resistance heat, and in any case it’s fully modulating so the house has stayed quite comfortable so far.
Evcept you spend more on it for no reason
That was in a worst case scenario though. I’d expect my furnace to reach closer to 80% duty cycle in a once in a lifetime cold front.
It’s better to have it max out in a 100 year cold snap, as they don’t happen too often, and it’s ok to drop a few degrees when that happens. Much more important to save money on your heat pump investment than spend thousands worrying about weather that never happens.
Technology Connections video about this problem:
https://youtu.be/DTsQjiPlksA
I thought working 100% for hours on end wasn’t recommended for a residential unit. Love me a Technology Connections episode, thanks!
yeah, I could be wrong, but that was the takeaway I got from the video, yeah. I have district heating so I don’t have first hand experience.
Even 100% on the coldest day is not per se an issue provided additional heat can be used. Space heaters, gas fire places, and baking being big ones.
Well, if cheating is allowed…
Ecobee also let’s you connect over HomeKit and allows you to control when the internet is out 😉at my old house I actually blocked the mac address for non internal and just had HA automatons take care of the rest.
Can you explain this? Not sure why but I cannot parse that sentence. You blocked external Mac addresses?
I tend to post then disappear lol but what the other person said: at the router level, I added a rule specifically to block a given list of MAC addresses. That included IP cams & the ecobee, then had HA act on data from other sources to adjust temperature.
The one I was proud of was 433mhz door and window sensors that, if opened for too long, would turn off the heat / air and just leave a fan on.
Not OP, but I believe he means he restricted outside internet access to that device (restricted communications to the thermostats MAC address to other internal devices)