Thermostat for HVAC fan when too hot?

[Sosalty]

New to wood stove heat 2 yr ago. I've learned and adapted a lot! Now, if I could just get a thermostat for my HVAC that would switch on only the fan when the room where my homestead/hearthstone woodstove is gets too hot.

We can control our heat via woodstove from about 75 to 80 in the living room, if burn is monitored the 1st 2 hrs, there's ample heat. Our mild cold heat is a reverse heat pump. Like others, our problem is the other end of the house being 8-9 degrees cooler than the living area with stove. Not fun to shower and even the bedroom isn't warm. (I know, wife has a 50 degree nose when it's 60, so lots of warmth in order.)

What we need is a thermostat that will start the fan when 80 is reached to cool down the living room and warm the other end of the house some. Seems wasteful to just turn the central HVAC fan on all nite. No AC or heat desired, just fan. Then if the living room goes under 75, the heat pump can assist until I get around to it.

When I search for such a thermostat folks get fixated on the fan only option, which we can presently do but not what we need. Is there such an HVAC thermostat to even out the heat without running the fan all nite?

 

[webby3650]

A simple box fan in the hall way is way more effective than a central furnace blower running. Not always the case, but for most homes there's too much heat loss in the duct system to be of much benefit.

 

[electrathon]

There are a few ways to do this. A lot will depend on your HVAC system. The crudest way is to simply install a relay that will disconnect your furnace fan from the rest of the system and kick it on with a basic line voltage thermostat. If your system is newer, there may be logic in your thermostat that allows programing the fan to do this. Many thermostats have manual fan control, this is the most likely. You can use a secondary low voltage thermostat to kick on the fan independently, bypassing the current thermostat for that feature.

 

[Sosalty]

Seems just asking the question clarifies some ideas. The box fan doesn't make it to the restrooms though it warms our bedroom. While there's some heat loss in the ducting, it's not problematic as the crawl space keeps above 50. If the living area is 81, the air from vents is 79. Thinking we can have the HVAC guy out to double insulate those ducts, enlarge the bathroom vents, and relocating the thermostat on an outside wall. Hopefully we can reset the fan for medium rather than high speed, then run the fan all nite. I know it won't be a complete solution but a noticeably help. Being new to wood heating, our system is working, we're pleased. Space heaters pep up warmth for a shower now, but a little more even temp thru the house would be ideal. It's our almost new 2 yr old retirement home and we're still tweaking it for max comfort.

I'm hesitant about double thermostats or changing the wiring though I appreciate the tips. The HVAC works as should now and I can kill perfectly working items.