How big is your home and how many tons is the system? Is it a variable speed air handler? Was you system properly sized? Is it short-cycling -- on 10 min/off 15/on 10/etc.? Were duct and load designs (manual D & J) done?

We have a 3100 sq ft 1.5 story ICF home and our monthly consumption is about 1000kwh (33/day) total for 2 separate 3-ton systems. We have spray foam attic insulation and a vented attic, with one system in the attic. But then, we had a complete energy-audit of our plans/D & J design done before we started.

The pros need way more info.

You think you are storing heat in your attic... try sealing it up and see what happens... it will be twice as bad. You probably need more ventilation. 50% soffit vents and 50% roof vents square inches wise is needed. Your large attic space will ventilate well if there is enough. Don't depend on what your builder put in to be adequate, they usually only do the minimum required to meet code. The height of the roof will cause a good draft due to the heat rising. I've read that ridge vents aren't the best method for the roof becuase they require the hot air to turn back on itself to release. Do you have insulation covering your soffit vents. Sounds like that may be a problem. Easy to clean off with a blower from the outside.

i have an encapsulated attic, radiant barrier no venting. basically my attic never gets hotter than it is outside. live in nor cal were we get 100+ in the summer. 1 hvac system is in the attic.

Mbarycki;

Your statement:

"I've read that ridge vents aren't the best method for the roof becuase they require the hot air to turn back on itself to release."

Could you clarify, please? Not sure what you mean, but I'm very interested since I have a soffit/ridge vent system.

Thanks.

V

msm859... what is an "encapsulated" attic? And, an RB needs at least 1 inch of air space between it and the attic below it in order to work, so how is your attic roof "encapsulated?"

If the OP's home is 9 yrs old, and the furnace up there is original, then it's very likely not high-efficiency with outside-air-source venting. So, the attic cannot be sealed because the furnace requires combustion air.

thought you would find this of interest!
study on spray on Radiant Barriers...
note that the OP used a company for his install
and not a diy.
it really makes a difference!
his RB achieves the same temp difference as my
install of single sided foil RB that I used button
cap nails to install.

http://www.hvac-talk.com/vbb/showthread.php?t=177709

dallasbill.... my attic is part of the insulated envelope. i have sprayed in foam insulation under my roof. i then have a radiant barrier that is double foil bubble wrap. i do not have any ventilation in my attic. my attic basically never gets hotter than whatever the outside temperature is. i have a 2 story and one of my ac air handlers is in the attic.