aux heat pump coming on?

[warmastoast]

Thanks to my electricity company finally providing energy consumption the day after, I can now see how much a couple of the biggies are using.  I've noticed that when the HVAC comes on, a lot of electricity is being used even though the temperature is set at only 68 degrees,  the overnight drop is to 63 degrees and it hasn't gone below freezing outside = lowest has probably been about 35 degrees outside overnight.
Then, this morning I had to go into my attic.  It must have been 90 degrees in there!!  This attic is very well insulated so it can't be warm air leaking up there and even so,  it was really much warmer up there than in the bedrooms below.  Initially I thought the ductwork must be leaking,  but I had everything checked and serviced on 11th december. Unlikely to be that although they did miss a problem last time they came.  So, I've called the HVAC people and they're coming back to check tomorrow.

Then I remembered that my son had noticed that the air coming through the vents initially was cold, and he's right it was because I had also noticed it.

I think my aux heat springs must be coming on unnecessarily.   High energy consumption,  a heated up attic and cold air at first.  What do you think?  What can I do?   My nest thermostat downstairs would make sure this doesn't happen by heating up the rooms slowly (it's designed to do this to save money) but upstairs I have a regular honeywell programmable thermostat.  I read that the aux heat will come on if there is a sudden need for increased heat , like when the thermostat is programmed to start up the heating and the temperature differential is too much for the regular compressor to cope with.  What can I do?  Where can changes be made?  I don't really expect the aux heat to come on when the temperature differential is only 5 degrees.

[lthenderson]

Then, this morning I had to go into my attic.  It must have been 90 degrees in there!!  This attic is very well insulated so it can't be warm air leaking up there and even so,  it was really much warmer up there than in the bedrooms below.

Then I remembered that my son had noticed that the air coming through the vents initially was cold, and he's right it was because I had also noticed it.

Not sure from your description but is your attic part of the conditioned envelope of your house? Are you accessing your attic from a stairway and the insulation you are referring to is in the ceiling? If this is the case, hot air rises and it will naturally be warmer than any of the rooms downstairs, even with no duct work going to it. If it isn't part of the conditioned envelope of your house and you access it through a trap door and the insulation is in the floor joists you are walking over and it is hot in winter, you most likely don't have enough insulation and/or ventilation. Most house don't have enough insulation. There should be 8 or 9 inches of fiberglass insulation.

With any forced air system, the initial air coming out of your vents will feel 'colder'. After your heat system shuts off, the air left inside the vents will cool down to ambient temperature. When the system kicks back on, this ambient temperature air needs to be purged from the vents before you will feel the heated air. You can mitigate this to some extent by insulating your duct work to prevent the temperature from cooling down rapidly.

[Uturn]

I'm not an HVAC expert, but my understanding is a heat pump does not need to turn on the aux heating coils until it gets below about 45*.  Are you having temps that low?  If not, I would contact your HVAC folks and have it looked at. 

The initial air coming out of your vents will feel cold for a few seconds, normal.  It will also feel hot in the summer.  I wouldn't worry.

Unless you have one of those super high efficiency houses built in the last 4-5 years, I doubt your attic is conditioned space.  If it's warm in there, I would suspect a leak.  Duct leaks are easy to fix, the hard part is only stepping on rafters and not drywall.   

[warmastoast]

Thanks for your replies so far guys!
Learning curve on all this has been a bit of steep one.  After more investigating and thanks to Google I discovered that we don't have heat pumps,  we have air conditioners and the handler in the attic has a strip heater to provide the warm air.  This done in 2009 by the previous owners.  Can we all join in with the face slapping?  Better, they replaced the 2 outside condensers, the downstairs handler but the upstairs handler is the original from 1985.  The ductwork is well insulated and doesn't feel warm to the touch.

The attic space I'm talking about is outside the building envelope.  We have 12 inches of insulation in the attic floor, the air handler is in this un-conditioned space.   I just got the service people back and they believe that all is running normally and that there is no leakage.  That the space is getting warm just from the outside temperature.  I can't quite believe this since yesterday's temperature in Austin was a high of 72F and a low of 48F.

Not sure where to go on this one.   My electrical consumption is high, my house is heated only to 68F for 1 hour in the morning and 3 in the evening. For the money it's costing me, I'd expect to heat it more.  House is well insulated - it's not perfect but pretty good.

[gecko10x]

If 100% of your heat is from strips, you might be better off to just set it super low and just use space heaters for whatever room you're in.

[Uturn]

All electric heat is terrible.  Through the 70's and 80's, the powers that be decided that electricity was more economical than natural gas.  What this really meant is it was cheaper for the developer to build neighborhoods without having to run gas pipe.  Heat pump efficiency in the early - mid 80's wasn't quite there yet.  Now, it is just dumb not to have one. 

If I had all electric, I would look at various space heaters.  Not the coil only ones.  I like my oil filled radiator type.  I hear the ceramic ones are good too.  You might be able to turn off the electric heat and use the oil radiators from letting the place get too cold, then use the central heat sparingly to be comfy.  Or the other way around, depending on which way is cheaper. 

You might also want to look at replacing your HVAC and water heater with a heat pump and see what the ROI is on that.  I would guess that Austin is about the right climate for heat pumps to make a lot of sense.