Those are not the ideal stats for HP or dual-fuel setups.
Those are low (cheaper stats) installed by unprofessionals.
I've seen my top competitor install those stats for Geo systems; and this customer had the gall to tell me that his Geo cost alot to run; he said it wasn't worth it (i wonder why?).
Generally only after the initial recovery run do the walls and furniture lag behind on temp, and its not for a few hours. Those of us that use set back know this, and are comfortable with it, since the walls and furniture catch up when the furnace runs the next time.
Originally Posted by motoguy128
A properly size furnace has no problem recovering a small 4 to 5 degree set back. Except on design condition days.
I believe both of you are forgetting that some thermostats allow the temp to drop 2 degrees before it brings the furnace on. So your saying that the furniture will never be warm in a house with one of those thermostats because the temp drops 2 degrees.
Envelope improvements will usually save more money then just set back. But set back does save money, and cost a lot less to do. And there are many home owners that can't afford to do the improvements to the envelope that would need to be done.
Back in the 80s energy crisis. Schools in this area were setting their stats back all the way or even shutting off their heat on weekends. Along with 10 degree set backs during the week. Those burning oil reduced their oil consumption by 100 to 1000 gallons a month by doing so(varied with size of school and outdoor temps for the month of course).
Back then I would have agreed with both of you that set backs don't save. But the evidence from those schools proved other wise. So I learned see back does save.
Yeah, spending 20 plus grand on envelope improvements will save more. But a good thermostat doesn't cost nearly that much, and does save money on the heating bill. And can save money on the cooling bill also.
Setbacks have a VERY important place when time of use/variable peak price electricity rates are involved. In our area power rates are typically 4 times as much between 2-7pm weekdays. 5 cents off peak, an average of 22 cents on peak. Setback saves BIG between 2-7pm. Don't think TOU/VPP rates are just in our area, they are becoming more widespread as smartmeter technology becomes more affordable for utilities.
Also consider AC units operate more efficiently as outdoor temperatures drop. Higher indoor temperatures during the peak hours of the day saves money on the utility bills. High temps can come from thermostat setback OR slightly undersized equipment. The smaller equipment would also have the advantage of no cycling losses during the hottest time of the day. No cycling losses while the small AC recovers after the peak heat of the day either...