Thank you so much both of you for your advice.
Our furnace fan runs when the a/c is on also. But that’s because that is what circulates the air. It’s not the actual furnace (no hot air), it’s just the furnace fan running. That runs at about 300 Watts for us, and it should only be running when the a/c is on - not continuously.
OK, that's what I sorta figured already, thank you. It is definitely not heating the house - I would have noticed that on our gas bill, which was pretty much NIL hast month. It is definitely not running 24/7, I already made sure of that. But thanks for reassuring me that it is in fact expected behavior.
I think you should start reading off your electricity on a daily basis and switch off one of the named devices every alternate day to see which one makes a difference.
I thought about that too, but have you ever tried turning off the A/C in central Texas between March and November? The house would heat up to more than 40-45°C within an hour or two. What I can do is turn off the PC and the light/fan in the office for 24 hours and see if they make a difference.
Are you sure your thermostat turns off you AC?
Yes, I can hear it turning on and off regularly during the day and less frequently in the evenings.
Could you have some devices doing the opposite? Like the new owner of our previous house who was having a fire in the wood stove, while the warmth pump was set to cooling the house down and running at full power. Now this person was not familiar with how the warmth pump worked. But could your central heating be trying to get the house on the temperature that the thermostat shows, while the AC is trying to cool it down?
While that would be possible in theory I don't think the current thermostat supports this. I have to actively set a switch to either "Cool" (left), "Heat" (right), of "Off" (middle), and I have a gas furnace in this house. Last month's gas bill was $3, which accounts for cooking and hot water, so I don't think that's the problem. I was considering something along these lines as main culprit as well.
I suppose no one from outside has somehow started to use your electricity?
That I can definitely rule out, yes.
Maybe your old AC unit was working so badly that it didn't use all it's capacity? If you calculate the difference between having the AC on and off, can you then calculate if that is normal use the for new unit?
I would if I could turn the A/C off but like I said: given the current outside temperatures I'd be boiling within less than two hours. It'll be late October / early November until I can safely turn the A/C off for more than a couple of hours. Also, as far as I'm informed that's not how A/C units work. The old unit was practically running 24/7 because the thermostat was set to 78F but the house was constantly at more than 80F. Accordingly, the A/C and fan were on all the time.
I did take notes of the power meter reading since last night, and apparently whole house consumption between last night, 6pm, and this morning, 6:15am, was 10 kWh, or 0.82 kW/h. I did, however, remember that I changed one setting on the thermostat at some point last month shortly after the new A/C unit was installed: instead of "Hold 78" I set a schedule for different temperatures during day and night. I have just reset this to "Hold 78" again and am going to keep my eye on the power meter. We've already consumed 229 kWh in the last 7 days, or 32,8 kWh/day, since the last reading. I'll see if that thermostat settings makes a difference or not in the next few days.