Here is an idea! If your unit looks like the one on the left. You can use River Rocks and crushed granite to build a solid foundation for less then $20. We just installed/replaced the one on the left with the one on the right. [6 seer to 15 seer] 3.5 ton Heat Pump system for $7300 [about $2500 savings] and didn't leave anything out. We have a limited qty of system at such a deep discount. Call us if your interested to see how much we can save you.