Programmable Thermostat

For comfort, ceiling fans produce a better air flow. IR Remote controlled ceiling fans about $150eh. Even have them for 12v RV's now for about the same cost.

With the tight built homes of today, a person really should be adding 25% of outside make up air/hr. That gets rid of all the off gasses of our mfg products, some really nasty chemicals.

Use the exhaust air to preheat/cool the make up air. A air to air heat exchanger can be made out of most auto raditors or condensors for a resonable cost. Besure to use new materials. And sanitize them twice year, bleach works well here.

T_Bone

With higher efficiency air cleaners becoming more and more common, the stat with programmable fan capabilities is becoming more common too. The reason they have become so popular is because of the fall and spring seasons where your furnace or air conditioner might not run...therefore the fan would never come on and give you the advantage of filtration...but a stat with this capability does.

It offers a fan mode of "On", "auto", or "circ".

In "circ" mode, the fan (only) is run randomly about 30% of the time the system would otherwise be off. I use this feature to get de-stratification and improved air filtering. This mode works really well with a heat pump that has an ECM type blower -- in "fan only" mode the blower runs at 1/2 speed and uses 1/4 of the electricity of full-on mode. Since the ductwork is sized to be reasonably quiet for the full speed of the blower, the fan-only mode is almost dead silent.

The TH8000 also offers outdoor temperature sensing and display, and the ability to lock out the "aux heating" unless the outdoor temp is below a threshold set by the user.

The RTH8500 looks like it is based on the same chassis, BUT the internal programming appears to have been "consumerized" and emasculated for the "big box store" market. A study of the owners manual shows no fan mode other than "ON" and "Auto". So it won't do what you want.

The other poster probably had it right -- the naive consumer thinks "the furnace is running" when it is just the fan. So Honeywell dumbs down the unit for sales to "Handy Andy".

You can buy a real "VisionPro" from several different internet vendors, assuming you can handle the product support and low voltage control issues yourself.

I really like my unit, but installation is definitely not for the faint of heart -- it takes 10 wires to hook up all the features (Power, return, 3 heat, 2 cool, fan only, outdoor temp sense, fault display).