I used Design Air for installing a new geothermal unit that replaced my conventional furnace and air conditioner. Their quote for geothermal was the best price I got when compared to other places. They are kind and courteous. They also got the job done in a reasonable manner. Cleaned up after they were done. They sell Water Furnace brand geothermal units which is a trusted brand. The geothermal unit has been up and running for around three weeks so far and no problems or issues. I really like the geothermal and the work that Design Air did. Looking forward to a lasting relationship with Design Air as they continue to service the new geothermal in the years to come.