My idea is to move cold air upstairs when there is a differential of more than say, 5 degrees. I would like to push the air in near the woodstove as it would help regulate the house in the winter when it is toasty upstairs and frigid downstairs. But it would also save some energy in the summer, when the AC sinks into the basement. Ideally, I’d like to push air from the hvac room up through the ash trap for the fireplace that has the insert wood stove in it, but I imagine there is probably some (justifiable) code saying that I shouldn’t do that. What are the rules about ducting air around gas furnaces and wood stoves? Any recommendations for price effective and quiet hardware I should get (fan and duct). I was going to look at amazon but I realize I may pay a premium for inferior products. Lastly, I’ll need to wire up a couple thermostats to calculate a differential, but I could use a switch for the short to medium term.
Insert woodstove is directly above hvac room. Also, I have a heat-pump water heater in the hvac room (small, with louvers).
I can't imagine trying to move air the opposite way than it normally wants to convect, especially not quietly. I would think you would need powerful fans to push hot air down and cold air up. Sorry, don't have any suggestions on how to do that.
I am thinking a supplemental fan to the HVAC, to distribute the air between the floors without multi-$k contractor to balance the HVAC and ducting. I try running the hvac fan and it doesn’t do much to get the cold air up or the warm air down. Someone on here mentioned that it is more effective to move cold air, since it is denser. Alternatively if I could source the air for the blower from downstairs, it would have a similar, if lesser effect.
If your HVAC system with sealed ducting and high CFM fans won't do it, whatever you come up with is going to have a hard time too. You may be able to use your current system...on the cold level, close off the supply vents and leave the return open. Do the opposite on the hot level. If that doesn't make a noticeable difference then moving air probably isn't the right solution to even out temperatures.
“Sealed ducting” is debatable. I’m not sure when the ducts were put in, but temperature distribution isn’t great within the house even on the same floor. Let’s pretend there were no return registers in the basement. Wouldn’t some supplemental air flow in the form of an extra fan or duct, help out the situation? I know modular ducting isn’t real commonplace, but I imagine there are some efficiency gains to be had. I have pretty much stayed off of the gas heat 90%+ by heating with my fireplace insert for the last few years, however the basement is quite chilly, where my “home office” is, when the hvac rarely kicks on. Also, the evenings tend to be a bit hot/cold on the main floor.
mrfancyplants Do some research on AC Infinity Fans. CLOUDLINE T6, Quiet Inline Duct Fan System with Temperature and Humidity Controller, 6-Inch This one has a temp and humidity sensor that can control when the fan turns on and it has a pretty long cord to the controller so you could locate it on your main floor to control the fan. They also have inline mufflers to quiet the fan noise if needed. The fans are pretty quiet unless run at the higher speeds. See my post in the EPA stoves area discussing what I did: Zero clearance fireplace vs woodstove in new build I ducted directly from the fireplace which was built for a duct system so mine works well. We're pushing hot air up from the basement though. I have turned it on in the summer and it pulls cool air up to our main floor like you are describing but I haven't left it running since our HVAC system works well. If you can seal your basement off from letting warm air escape upstairs, I would lean towards pumping hot air down to the basement in the Winter if you have an efficient way of capturing hot air directly around the stove that is much warmer than the room air. If you do the opposite and push cool air up around the stove, you're still going to be pulling cool air into the basement from other areas of the house. I'm envisioning a larger sleeve installed around the stove pipe with a T adapter that feeds air into a duct. This way you are capturing heat that was going up the chimney possibly making your stove more efficient and not pulling heat away from the stove. You would place the fan in the HVAC room and you could pull hot air down. If it were me I would run the basement duct work into a wall vent outside the HVAC room so you avoid messing with any air in the HVAC room. Your furnace is going to be pulling combustion air in when in use and you don't want to overheat the HVAC room. See attached crude sketch for the stove pipe contraption I'm envisioning. I don't think you would notice much difference in warming up the basement unless you have much warmer air being captured and pulled down. The air coming out of our vent on the main floor is between 120-140 degrees depending on the speed of the fan. On high it settles around 125 or so. The middle speeds end up having higher temperatures because the air being pulled in around the fireplace has more time to heat up. These AC Infinity fans use pulse width modulators on DC so they are very energy efficient. See the chart I pulled from one of the Amazon reviews on this motor for the energy used at the different settings. Fire code I think is your bigger issue so you will want to make sure you don't create a fire hazard with what you are trying to do.
Awesome, this will give me a lot to think about, and I’m sure I’ll be rereading it a few times. Thank you for the input. And I think that is just the sort of hardware I might need. We have an open stairs between the levels, but I was thinking if I blew cold air up from the basement past the stove, I could have another one set of at the far end of the house taking air down.. it would be a double benefit of drawing the warmer air through our bedroom and down into the guest bedroom that gets really cold when the furnace isn’t kicking on. I like the idea of harvesting that stovepipe heat, but not sure if I could with an insert(stove in the fireplace. Of course I wouldn’t risk any fire hazards; but I wasn’t sure if ducting through the ash trap towards the stove would be a no-no(only guessing).
Ah, I missed that you have an insert Disregard my design suggestion A few pictures might help to understand what you are working with.
I know, not a lot of space to work with. That’s why I was thinking the ash trap could be ducted to bring up air to the blower.
That’s helpful to see. After seeing the picture, I would suggest having someone from your local insert dealer out to see if they have any suggestions. The open floor plan between levels I think is going to make it almost impossible to keep the warmer air from rising and cooler air from sinking. If you do get the basement comfortable, it’s probably going to mean the rest of the house is too warm unless you can seal off the basement to keep the warm air down there. Our first home was an open split level design with a fireplace on the lower level that was open to the main floor and 3rd level. You could feel the heat from the fireplace while sitting next to it but all the warm air just went up to the rest of the house
I know it is s tall order to heat a house with an insert, but it is so much fun chopping and hoarding, I figure why not. I have done a pretty good job minimizing the gas bill, but the main thing is when we have guests in the guest room, I pretty much need a space heater down there to keep them comfortable, especially if the stove is running. I feel it couldn’t hurt to mix up the air between the levels some, but ideally I’d run some sort of radiator in the far corner of the house.
You might want to look up "whole house fans". Basically a big fan upstairs that would pull the air up, I am not sure how it would work in the winter though. I think they were popular pre air conditioning. Also, there is a stove design where you can vent your insert so you have holes on the 4 corners of the frame. This allows air to enter and exit from around the stove rather than relying on a blower. If you do hobby technical things you could probably make a thermostat with a raspberry pi. I bet they have kits for that. If temp > (temp - 5) turnOnFan
