Outside PCB in between ₤ 300- ₤ 2000 dependant on the size of the system and maker. https://www.beoku.com/cart/addtowishlist?backpage=https%3A%2F%2Fcanvas.instructure.com%2Feportfolios%2F2807580%2FHome%2F_Why_Proper_Air_Conditioning_Installation_Matters_for_Your_Comfort_&prodid=6005