Yes, if you install radiant heat in a slab it does have a slow responce time but I believe there are ways you can work around this. It may not be enough for you to worry about, first of all. If you can wait 6 to 12 hours to get up to the temp you want than leave it. Another option is to see if theres a control that will accept signals from a phone line or computer access to turn it up when you tell it youre coming. I am sure these are out there but I just dont have a link available for you right now. If you cant find anything out let me know and Ill do a little research.