I need to replace two 30 year old heat pump units. I'm feed up with $600-$800 month electric bills. So, I'm considering going with the Frigidaire iQ 23 SEER 4 ton units. First question, what do folks think about this model? Second, do you think the energy savings are worth the upfront cost compared with say a 14-15 SEER unit? Lastly, I'm considering trying to convert from electric to gas and I know the Frigidaire iQ comes in both a gas and heat pump version and I'm still trying to get a handle on the cost of upgrading my gas service to accomodate the gas units, but putting that aside somewhat, is the gas version going to save me a lot more down the road compared to the electric heat pump version to make this switch worth it? I'm dealing with the North Texas climate area. Any help is appreciated. Thanks!