I have used Northwind for years and have always had good experiences w them. I am a Realtor and also use NW clients’ homes to come in after inspections and give use the real scoop on equipment condition. Several years back I had a vacant new construction house for sale. No one could figure out why my client was having outrageous electric bills. NW figures out that the AC systems were 2 stage had been programmed wrong and were running all the time, costing homeowner a fortune. Once the problem was resolved the electricity bills were literally 50% what they had been.