We recently built a 1400 sq ft, 1.5 story (with a full basement - unfinished) vacation home in Wisconsin. The HVAC contractor installed a "high efficiency" Frigidaire furnace (sorry, do not have the model number). The builder told us that we should not turn down the thermostat lower that 55, and that Frigidaire actually suggests no lower that 60. Why do we need to keep the house that warm if no one is there for weeks at a time. We thought 48 degrees would be better. With the price of propane, is 55-60 really necessary?

They are worried that the heat exchanger in your furnace can not take the rapid expansion from a very low temp to the heat of the flame, it might crack the exchanger. However, I set mine at 48 and never have experienced a problem since installing it in 2005. If you have a router you can control your temp from any computer or smart phone with a Honeywell TH6320WF1005 WiFi Focus Pro Thermostat I bought mine at Home Depot form $100. Let me know if you have a router and what to try this.