Thread for discussing money saved with OpenHAB

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I forked this discussion out of the Control a water heater and ground source heat pump based on cheap hours of spot priced electricity - #152 by masipila group with the purpose of focusing on boasting on savings achieved with applications on Openhab. @masipila promised to chip in. Here is my savings report for April 2023:

Just got my electricity bill for April 2023:

Consumption 854 kWh
Average cost 5,73 c/kWh
Margin 0,22 c/kWh
Monthly fee 4,36 €
Total bill 55,15€

References
Local energy company
Cost of energy 13,18 c/kWh
Monthly fee 2,5 €
Total cost would have been 115,06
Saved: 59,9€

Average spot price
April 6,661 c/kWh
Difference: 0,93 c/kWh = 14%
Saved: 7,95€

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What a great idea.

While my saving isn’t so dramatic, it’s worth mentioning.

When I first designed our house some 7 years ago, I put a PIR in the kitchen for two tasks.

To turn the light on when the room was dark and something moved (but not when it was naturally light)

Secondly to turn on an under cabinet water heater for 20 minutes, restarting the timer on every new movement.

This worked and I thought no more about it, until recently when I started working at the kitchen table, instead of my office (just for a change of scenery).

That very first day I noticed that our electricity bill was £2 more than the day before, and was ~£2 higher every day that I worked in the kitchen.

Had I not installed that PIR, the little heater would have cost us £2 every day, regardless of us being there or not.

So yeah, £60 for a fancy light switch with a built in PIR and a individual relay at £70 was an investment, by my thinking, it paid for itself in 65 days.

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I recently ordered automated z-wave shades (Bali Blinds via Costco), because my east-facing, top-floor condo traps heat in the summer and doesn’t let go of it. The double-cell celluar blinds I’m installing are supposed to reduce solar heat transfer by 60%.

I expect to reduce my air-conditioner usage as a result, but the reality is that the shades cost me $2k and I’ll never save enough on energy to break even. It’s more about increasing comfort and reducing energy consumption. :wink:

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Unfortunately it’s really difficult to come up with real numbers in my case but I could maybe back into some. If I remember I’ll come back later with a guestimate of my savings.

Where I live natural gas and electricity are relatively cheap and it’s the same code no matter when you use it. Electricity is so cheap it’s not always a good investment to put in solar power. However, our water is relatively more expensive (though it’s the fees and sewer that really adds to the cost). Unfortunately our Home Owner’s Association hasn’t caught on to the fact that we live in a high desert, have been living under drought conditions for two decades, and we are running out of water. They still require a certain percentage of the property be lawn and I’ve a relatively large plot.

I’ve installed a Rachio which has saved about $100 a month during the summer months alone. But the weather forecast isn’t always that good and there are days where it waters even when it doesn’t need to because a thunderstorm formed just over the mountains and dumped on our neighborhood unexpectedly (weather is highly localized here). So I’ve augmented the Rachio with weather info weather services to skip a watering when that happens. Eventually I plan on putting in my own weather station to get even better localized information.

But one reason it’s hard to figure out how much I’ve saved is because I have to retroactively check to see when the sprinkler was cancelled by OH due to weather and not the Rachio itself and I don’t have an easy way to do that. And I can’t just compare this year’s to last years bills because for the past couple of years I’ve been trying to get new grass established where a fungus killed it dead. We’re tired of dealing with muddy dogs.

I’d estimate we use about 1200-1700 gallons every time we water. At about a penny per gallon (not counting the service fee and sewer) that’s $12-$17 saved for every time I don’t water. I’d guess maybe ten times over the course of the growing season OH will cancel a water that Rachio wouldn’t have cancelled on it’s own anyway so it’s a savings of $120-$170 per year.

It’s not a huge savings but it’s something. It almost pays for the weather station I want to build. :wink:

I wish there were devices that would be easy/possible to retrofit to existing blinds, particularly roman shades. We have a really large west facing window (5’ x 7’). I custom made a roman shade with great insulation and blackout properties but it’s heavy. I’d like to be able to control it so in the afternoons it goes down on it’s own and comes up in the morning. But they don’t make anything off the shelf strong enough to open it. That would probably save a good bit on AC in the summer given the thermostat for the whole house is in that room.

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Maybe put in a Zigbee/Z-Wave soil meter? I’m actually surprised that Rachio doesn’t have a soil meter of their own.

Yeah, the choices are pretty limited at this point in time. I love my current cellular blinds, which open at the top and the bottom, but that’s not possible with automated blinds. If I have space in the windowsills, I might keep them in place so that I can have the best of both worlds (plus an extra sun-blocking layer).

I forgot to mention that the new blinds will retain more heat in the winter. That will help a bit until the condo corp replaces our aging windows in a few years.

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They do offer a weather station but it’s a little pricey. I think it lacks a rain bucket too so it can tell you that it’s raining but not how much fell, and it’s the later that matters when it comes to deciding whether watering is needed or not.

There are challenges with using soil moisture meters in the lawn though. Mowing, tripping, dogs digging things up all become a hazard to the sensor. Power and communications is a bit of a challenge to. I think that’s probably why they don’t do it. Just using the weather and rain sensors is probably close enough for most purposes. Anything more is diminishing returns, at least i most parts of the world where when it rains it rains everwhere. Where I am an area less than half a mile in diameter could see a half inch of rain and just a hundred feet outside that area receive none at all.

Gardening is challenging to say the least.

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I achieved even higher savings in March, as the local electricity company was then selling energy at 16c/kWh:

1-31.3.2023

Consumption: 1201,96 kWh
Average spot price paid: 7,26 c/kWh
Energy bill total: 90,81€ including tax and 0,22c/kWh margin

At the same time our local energy company was providing one of the cheapest fixed energy prices in the country at 16 c/kWh. 1201,96 kWh x 0,16€/kWh = 192,31€

Total savings in March 101,5 €.

Total savings since I got the spot price control of the heat pump working at end of feb is around 150€. I paid around 60-70 € for the Orangepi 3LTS board and wifi relay that I connected to the heat pump aux.

What do I do with all this saved money? :wink:

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I’m a Tibber Pulse customer in Germany. Without Pulse, I would be billed according to the dynamized Standard Load Profile (SLP) H0 published by Standardlastprofile Strom | BDEW.

Saving money by shifting usage of white goods into cheap hours:

grafik

Starting the dishwasher tomorrow(+) at 13:01 will save 0.22 cents (compared to highest price) - for details see Optimizing energy costs (washing machines, tumblers, dishwashers, ...).

A difficult question to answer is whether it makes sense to use the Pulse when there are no electric vehicles and/or photovoltaic systems involved.

I use KNIME Analytics Platform to compare the cost based on the SLP to the actual cost based on consumption measured (and billed) by my Pulse. Example for May 2023:

SLP calculated (one bar corresponds to one hour):

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grafik1829×927 25 KB

Consumption (arbitrary units):

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Comparison billed vs. billed without Pulse:

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If there is any interest in such “what if” analyses, I could write a tutorial on how to integrate the KNIME output into openHAB.

BTW, here are my final results for April 2023:

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So the preliminary answer for May 2023 and the definite answer for April 2023 is: yes, using Pulse makes sense and did save 4,01 EUR (compared to SLP) in April 2023 …

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Buy more stuff to plug into openHAB? :wink:

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Here is the heating plan for today calculated by the OpenHAB scripts based upon outdoor temperature and wind forecast, incoming solar radiation forecast and day ahead electricity spot prices. Yellow bar is the planned heating time by OpenHAB, blue area is electricity price during the day. Money saved.

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Here’s the output of my openHAB based Energy Management System for my own home month-to-date.
I run a heat pump on Tibber using the algorithm we discussed in the other thread.

‘Kosten ohne EMS’: cost without openHAB
‘Kosten ohne PV’: cost with EMS but without solar plant (i.e. EMS operating heat pump using Tibber)
‘Deine Rechnung’: total bill of my EMS operating household appliances on solar power and dynamic tariff combined with heat pump, factoring in grid feed compensation

savings2
savings21920×1027 96.8 KB

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TBH my big money savers derive from the fact that my house is “thermal friendly” (good walls and windows) and I have 11 months of non-cloudy weather per year, which allows me to make good use of solar panels (to produce electricity and hot water). But OH helps a lot in optimizing:

  1. Automatic temperature control of my heating: I have sensors to measure outside temperature and set temperature targets for heating (air conditioner and pellet stove). Reduces both electricity and pellets bill
  2. heating is controlled by zone using PIR sensors and calendar
  3. My solar panel to heat water comes with an electric resistence. Originally it switched on every night during winter. Now, with OH and a temperature sensor, it only switches on when needed, and only during the time required to achieve target temperature (dinamically calculated by number of people at home)
  4. garden watering: using moisture and rain sensors I keep my water consumption to the minimum

I estimate OH monthly savings ~20€ (5x cold months), and ~5€ in warm months.

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Tonight the electricity price is negative here in Finland in the night and near zero during the day.

It’s crazy. It’s party!

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kuva1432×877 28.1 KB

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Is that including transmission cost ?
Net negative cost is not all that uncommon, in Germany I’m seeing it at least once a month.
But with ~16ct for anything beyond pure kWh i.e. transmission, taxes etc that’s still no reason to party :unamused:

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Now that’s interesting, I think/hope. So far I’m optimizing by demand air ventilation (on humidity, CO2, VOC and presence) because that causes my biggest losses. But I’ve noticed the incoming solar radiation has a influence on heating. Of course the heatpump will respond to that but I’ve been thinking about anticipating. If I know a sunny day is coming, I could heat a bit less the night before.

So I’m curious how your script takes this factor into it’s calculations!

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If I understood your question correct, yes my script corrects the heating plan for tomorrow based upon the solar energy forecast for tomorrow. It does that by reducing the number of hours my heating stays on.

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The price is excluding transmission, which is 9€/month plus 3c/kWh.
Negative electricity price is not very common in our market.

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My biggest saving came from being able to control a pool pump.

Originally it ran 24x7 (0.9kwh)
As it is a 15amp, the easiest solution was Aeotec 40amp inline + Z-wave dongle

which is what got me into Automation and thus openHAB

So for an outlay of;

  • Raspberry Pi 3b (now 4)
  • Aeotec inline plug
  • Z-Wave dongle

say NZD$500 I pretty much saved that in the first 2x months of operation.

Now 6 years in …

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You did. I was interested in the how, but I found code (using a webservice) in the other (huge :innocent:) topic And some more, using the AUX on the NIBE heatpump to control on/of of heating and the remark that there’s profit in spring/autumn when heating and cooling may occur on the same day. I’ve also noticed that and my simple solution for now is manually disable heating at a certain day. So new ideas for the future, thanx!

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Börsenstrompreise am 21.05.2023


 0:00 | + |   6,21 Ct/kWh | ########
 1:00 | + |   4,76 Ct/kWh | #######
 2:00 | o |   4,03 Ct/kWh | ######
 3:00 | o |   3,42 Ct/kWh | ######
 4:00 | o |   3,56 Ct/kWh | ######
 5:00 | o |   3,36 Ct/kWh | ######
 6:00 | o |   3,66 Ct/kWh | ######
 7:00 | o |   3,28 Ct/kWh | ######
 8:00 | o |   2,38 Ct/kWh | #####
 9:00 | - |   0,25 Ct/kWh | ####
10:00 | - |   0,00 Ct/kWh | ####
11:00 | - |  -0,06 Ct/kWh | ####
12:00 | - |  -0,94 Ct/kWh | ###
13:00 | - |  -2,98 Ct/kWh | ##
14:00 | - |  -4,92 Ct/kWh | 
15:00 | - |  -2,33 Ct/kWh | ##
16:00 | - |  -0,05 Ct/kWh | ####
17:00 | o |   0,26 Ct/kWh | ####
18:00 | + |   4,92 Ct/kWh | #######
19:00 | + |  10,17 Ct/kWh | ##########
20:00 | + |  10,81 Ct/kWh | ##########
21:00 | + |  10,83 Ct/kWh | ##########+
22:00 | + |  10,70 Ct/kWh | ##########
23:00 | + |   9,94 Ct/kWh | ##########


Bruttopreise. Inklusive Mehrwertsteuer (MwSt.).

Börsenstrompreise am 28.05.2023


 0:00 | + |  10,36 Ct/kWh | ##########+
 1:00 | + |  10,00 Ct/kWh | ##########
 2:00 | + |   9,75 Ct/kWh | ##########
 3:00 | + |   9,27 Ct/kWh | ##########
 4:00 | + |   9,27 Ct/kWh | ##########
 5:00 | + |   9,10 Ct/kWh | ##########
 6:00 | o |   8,57 Ct/kWh | ##########
 7:00 | o |   7,72 Ct/kWh | #########
 8:00 | o |   4,49 Ct/kWh | ########
 9:00 | o |   0,00 Ct/kWh | ######
10:00 | - |  -0,37 Ct/kWh | ######
11:00 | - |  -2,15 Ct/kWh | ######
12:00 | - |  -5,80 Ct/kWh | ####
13:00 | - | -15,46 Ct/kWh | 
14:00 | - | -15,47 Ct/kWh | 
15:00 | - | -11,67 Ct/kWh | ##
16:00 | - |  -2,22 Ct/kWh | ######
17:00 | - |  -0,01 Ct/kWh | ######
18:00 | o |   5,95 Ct/kWh | #########
19:00 | o |   8,68 Ct/kWh | ##########
20:00 | + |   9,52 Ct/kWh | ##########
21:00 | + |   9,26 Ct/kWh | ##########
22:00 | o |   8,78 Ct/kWh | ##########
23:00 | o |   8,27 Ct/kWh | ##########
```
1 Like