Electrical usage for your house???

[dmccarty]

Our last bill was around 1500 KWH for 30 days. With 720 hours in a 30 day month that averages 2.08333 KWH per hour.

And we are in a 2400 sf house with 10 foot ceilings which is a big volume of space to cool. We do keep the thermostat between 80-82 though. Your usage is almost 40% higher than ours for a smaller house! Course we aint in Tejas either and the weather has not been that hot over the last billing cycle but your bill still seem high.

I am likely repeating my self but its not the first time. Our city house was 1250ish sf. Not well insulated and it might have averaged 8 foot ceilings. Our power bills in the city house was about the same as our current house which is about twice the size. We had a new heat pump in the old house AND it was on city water so we did not have to run a well pump. The extra power was due to the heat pump. We were shaded too so we did not have alot of heat gain from the sun like we do in our country house. All of the appliances were new or newish with the exception of the water heater but it was only 40 gallons compared to the 80 gallon tank in the new house.

Is your extra power usage due to AC?

Later,
Dan

 

[EddieWalker]

Yes, it appears that the AC is killing me. My twelve month history show's November being right around 1,600 kWh. The graph shows a steady decline in how much electricity that I use from a peak in July. Every month to the end of the year is just a little bit less. The temps are down now and summer is over here. For the next couple months, the temps will be very mild.

I'm now wondering how much of my usage is because she has to have the AC on all night long. I'm also wondering if there is a chance that my compresor, or some other part of the HVAC system is bad and drawing more energy then normal.

Does anybody know how much they should use? What would be normal?

Thanks,
Eddie

 

[dmccarty]

Hopefully one of the TBN HVAC experts will jump in....

If one looked at the circuit breaker for the heat pump, divided it by half or a 2/3s it seems like that might be a good guess as to what the system uses once it is running. I know the compressor eats lots of power at startup but then is more efficient.

If the heat pump is on a 40 amp circuit it might be a good guess that it is pulling 20-30 amps, hopefully 10, after startup. If the voltage is 220 and the pump is pulling 20 amps that is 4,400 watts. Or 4.4 KWHs Running 12 hours a day that is 53 KWHs. For a 30 day month that is almost 1600 kWHs just in the AC!

Be curious to see if someone knows how much power the heat pumps consume.

Later,
Dan

 

[Scooby074]

Have a look at your heatpump unit. There should be a nameplate on it with Amps/Voltage maybe HP. THis would be a good place to start.

In our old house we had a first gen water to air HP. That thing was a energy pig!!! Wasnt sized properly plus the house wasnt all that well insulated (for a 1984 built home). A few weeks back i looked at a newer 3yr old house, with a Air to air HP, 2200 SqFt, total power bill for the year was $1700 (heat/ac/hotwater).

However your current usage doesnt seem too far off normal.

 

[heehaw]

i think the compressor will have the amps on the tag that shows the size an model etc. a clamp on ampmeter would answer that question really quick: any chance your duct work is disconnected somewhere an your trying to cool the world? that happens a lot an folks never know it. what i like to do is measure the current draw of a piece of equipment, an then figure how much it would use if it ran 24-7: that would be the worse case possible: things like my frig an freezer, either are any big deal..$10-15 a month if we left the doors wide open an they never shut off: then some time try to time how long the ac runs and how long its off before it comes on again.. i know theres probably a meter that could be hooked on the system to measure that for you, but my timex gets me in the ball park.
now what is a "mulitplier?"..are they saying the meter measures 1/8th of the electricity used, so then you mulitply by 8?? or because you are commercial, you mulitply the $$$ by 8??
heehaw

 

[dex3361]

Yes, it appears that the AC is killing me. My twelve month history show's November being right around 1,600 kWh. The graph shows a steady decline in how much electricity that I use from a peak in July. Every month to the end of the year is just a little bit less. The temps are down now and summer is over here. For the next couple months, the temps will be very mild.

I'm now wondering how much of my usage is because she has to have the AC on all night long. I'm also wondering if there is a chance that my compresor, or some other part of the HVAC system is bad and drawing more energy then normal.

Does anybody know how much they should use? What would be normal?

Thanks,
Eddie

Just installed a 14 seer Goodman Heat pump 3 ton and it pulls about 9 amps (87degrees outside 74 inside) and it will vary depending on the temperature seer rating of the unit even the humidity inside/outside. If you could give the brand and model # of the unit it could be looked up. Mind you the amps will vary within a range.

 

[EddieWalker]

Not sure if I got the right information, so please let me know if I missed something.

The picture is a big fuzzy, but I'm hoping that it's clear enough to those who know what they are looking at to see what I have.

Here is what I wrote down. It's not everything, but what I think is pertinent.

Ameristar

mfr date 5/2005

Mod No 2A6B2030A1000AA

Minimum Circut Ampacity 18.0 Amps

Compra Mot 13.5 RLA

O.D. Mot .90 FLA

208/230 V 73 LRA

200/230 V 1/8 HP

f ID F75

 

[BobRip]

Not sure if I got the right information, so please let me know if I missed something.

The picture is a big fuzzy, but I'm hoping that it's clear enough to those who know what they are looking at to see what I have.

Here is what I wrote down. It's not everything, but what I think is pertinent.

Ameristar

mfr date 5/2005

Mod No 2A6B2030A1000AA

Minimum Circut Ampacity 18.0 Amps

Compra Mot 13.5 RLA

O.D. Mot .90 FLA

208/230 V 73 LRA

200/230 V 1/8 HP

f ID F75

Compra Mot RLA - Running Load Amps (pretty sure of this) for your compressor. Your meter will probably read a little less than this at the temperatures that you mentioned.

LRA - Locked Rotor Amps - If the motor is held from turning over this is what you would measure. This is like start up current.

Not sure what O.D. Mot is but it sounds like the fan. So the .90 is the Full Load Amps of the fan.

Do you clean the evaporator and condensers coils (inside and outside coils) every six months. This can be a big factor in power consumption. I think you should have a pro check you AC out.

 

[dex3361]

Eddie
I can only find the newer model of the 3 ton amerastar AC but the amps will be very similar and they are listing the Run Load Amps as 9.5. Here is a link to the Spec sheet and you can see look at the model #2A7M3030A1. Keep in mind it can swing down from that depending on the out/inside temps.

http://www.trane.com/webcache/un/split system air conditioners (ss)/product/12-1218-03_04012009.pdf

 

[tallyho8]

Eddie, I've only serviced air conditioners for 38 years and it was mostly window units so I might not be as experienced as some of the others but, I figure that your air conditioner should pull 14.5 at 95 degrees outside temperature. At 85 degrees it might only pull about 13 amps.

Your unit seems to be pulling higher than normal amps if you checked it at 15 amps when it was in the 80s. Now you need to find out why it is pulling high amps.

In post 32 I told you that a dirty condenser coil can cause it to pull high amps. Your coil must be clean on BOTH sides because only one side gets dirty.

Corroded wiring will make the unit pull high amps. After the compressor has been running a while you can turn off the circuit breaker and quickly feel all the wires especially near their ends to see if they are overly warm. Be careful around the capacitor, it may still have a charge so don't touch any bare wires. Be sure to feel the wires right near where they hook to the compressor and to the circuit breaker box and by the main relay. Also see if your circuit breaker feels warm.

Any corroded wires will be much warmer than clean connections. If any hot wires are found they should be disconnected and checked for cleanliness.

I have also seen units with compressors that pulled too many amps due to internal wiring problems. A weak capacitor will also make it pull high amps.

I assume that your condenser fan motor is hooked up to the proper speed and has the proper factory fan blade on it.

 

[dex3361]

Eddie
I can only find the newer model of the 3 ton amerastar AC but the amps will be very similar and they are listing the Run Load Amps as 9.5. Here is a link to the Spec sheet and you can see look at the model #2A7M3030A1. Keep in mind it can swing down from that depending on the out/inside temps.

http://www.trane.com/webcache/un/split system air conditioners (ss)/product/12-1218-03_04012009.pdf

Eddie that is just for the outside unit, you would check the amp draw at the disconnect beside the outside compressor. The inside unit would be checked seperately.

 

[Scooby074]

Eddie, from what ive seen so far i dont think your AC is out of the ordinary. Readings can vary depending on your meter and the motor itself. Check any other components of the system with their respective nameplates.

 

[smfcpacfp]

I have a 1,500+ sq foot log house in one of the colder parts of the country. Our monthly bill shows a graph of the monthly useage. It averages about 1,000 Kw from a high in the winter of 1,100 to low of 800 in the summer. I always felt like a electircal hog, but I feel better after seeing what others use. We don't have air conditioning. There are only two of us now. My remberance was that there was more useage when our two children lived here.

I think something is wrong Eddie.

 

[heehaw]

"Keep in mind it can swing down from that depending on the out/inside temps."
how does it do that?
heehaw

 

[irvingj]

Amperage on a refigeration unit will vary according to load.

In AC, high outside temps = high pressure on high side = higher amps; high inside temps = expansion valve opening to allow more refrigerant into evaporator = higher head pressure = higher amps.

As the load or outside temp tapers off, amperage will drop as well. Just like driving a car uphill vs. on a flat or downhill. (Heehaw--lots of people don't realize this.) As pointed out, FLA means "Full Load" amps, which should be a max under normal circumstances.

 

[dex3361]

Amperage on a refigeration unit will vary according to load.

In AC, high outside temps = high pressure on high side = higher amps; high inside temps = expansion valve opening to allow more refrigerant into evaporator = higher head pressure = higher amps.

As the load or outside temp tapers off, amperage will drop as well. Just like driving a car uphill vs. on a flat or downhill. (Heehaw--lots of people don't realize this.) As pointed out, FLA means "Full Load" amps, which should be a max under normal circumstances.

Well said

 

[Chuck52]

like Tallyho said, cleaning the coil can make a big difference. My SIL is in HVAC and he serviced my unit a couple of years ago for me. It needed a little freon, but the major difference he mad was in cleaning the coil. I didn't keep track of the electric usage but the difference in how much the system ran was dramatic. Since then I've kept is hosed down myself.....doesn't take an HVAC expert to pop the top and squirt water through the grid.

Chuck

 

[EddieWalker]

Tally got me to wondering what the coils and terminals look like in the compressor. I had a really busy day today, so I asked my dad to take a look. I also printed out some of your comments and suggestions. With that, he looked at the coils and determined them to be nice and clean. He looked at the terminals and also said they were good. He set the AC to 65 degrees and while it was running, he felt the wires, which were cool.

He then went to do the same on the inside, blower unit. I'm drawing a blank on what it's called. The filter was clean. I change it the first of every month. I've never opened it up, but Dad did. The heating coil is spotless.

But he did find a big suprise.

The insulation that lines the sides of the unit was sucked into the fan or blower. It's a wonder tha any air got through the insulation since it was sucked in there so badly.

He had already pulled it out when I got home, but he didn't know what to do in order to stop it from happening. The first picture shows it starting to get sucked back into the fan/blower again. Just in the picture, it's amazing how much air the insulation blocked.

I found a metal screen/grill type of thing in my scrap pile that fit after cutting it down to size. Then I wedged in a length of scrap 2 inch PVC pipe to hold the grill in place. There is now a large gap between the insulation and the fan.

I'm hopeful that this will allow the air to flow freely, which should require allot less power and electrical usage.

Thank you.
Eddie

 

[irvingj]

Yep, Eddie you got it! With a lack of airflow over the evaporator, the coil would likely ice up, further restricting airflow.... it's a vicious cycle that will:

a) cause your house thermostat to say, "Hey- we need more cooling! Keep running!" (and not get any...)

b) Do bad things for the compressor (eventually), as the liquid will NOT evaporate in an iced-up evap coil (no source of heat), and potentially --likely, after a bit-- send liquid back to the compressor...

That insulation "plug" alone would make your compressor run a lot more than it should. If it sounds OK (no loud rapping noises like loose valve-lash on rocker arms in a gas engine), it's probably OK- compressors are pretty tough, actually. If it did pump liquid, the valves-- spring-loaded flapper type, most likely-- are usually the first to go. You might wish to check it's efficiency: you should get about a 15 degree drop over the evaporator, between incoming air and discharge air, assuming humidity isn't extremely high. (I keep thermometers on my heat pump all the time for that purpose- one at the filter and one in the discharge duct.)

Your wire mesh-over-the-insulation solution should be perfect.

 

[jinman]

Eddie, good work by your dad and you both. Too bad you didn't find that back in April before the cooling season. It's so cool now that you probably won't know if it'll make a difference until next spring/summer. I'm sure you will also heat your house much better with the increased flow, but our heating needs are so low here in Texas that it won't make as big a difference is my guess.