Does anyone "insulate" their masonry fireplace before installing an insert?
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If the insert you buy is worth anything, you won't need anything but a block off plate. My insert sits right on my hearth and there really is not much heat coming off the back as they are designed to send it out into the room.
Depending on the speed of the fan the outside of my insert is anywhere between 80-120F on the sides/back and 400-600F on the top. I've been up and down that thing with an infrared thermometer and was very surprised by the lack of heat in the back of the fireplace. The boiler has more of a impact on the temperature of the old firebox than the insert, thanks to a 600F stack temp of the old system. Even with the stove off the walls of the firebox were in the mid 80s while the rest of the house was in the low 60s. That will no doubt change this year with the boiler upgrade last Spring. They have seperate flues but are together in an exterior chimney.
Having played with AL foil enough (both with atticfoil in my attic and AL foil here and there with my stove... don't askBeGreen said:
) I'm inclined to believe what pook is saying here, assuming the foil is somehow secured against the masonry well enough. You don't want the foil touching the insert at all or else it's all for nothing (AL foil prefers to transfer heat by conduction and is incredibly efficient at doing so, but it hates to accept or send its heat by radiation). But lining the masonry back with foil assuming it won't touch could be a viable way to do it. Assuming the insert doesn't touch the foil, the foil on the masonry back will reflect almost all IR radiation from the back of the insert right back at it, which will also make the insert a little warmer back there. That's conserved heat energy at the very least--heat energy that is *not* making its way outside via the masonry back. If you had some ability to touch the masonry behind the foil while the insert is in operation, I'd be willing to bet it'll be stone cold, or at least significantly cooler than the rest of the masonry nearby that is *not* foil-covered.It's not the traditional "R-Value" form of insulation, but having R-value insulation (rockwool, cement board, etc.) would work pretty well too obviously. AL foil just might be the cheapest way to do it. It's a MacGyver trick I'm keeping in my back pocket now that I've played with it a bit. Probably would look ghetto to most chimney sweeps but it's worth a shot if money is tight or options are tight. Always better to do it "right" though.
It occurred to me that no-one has given the ussual warning to the OP: "Do not pack insulation on or around your liner!" Insulate the fireplace it you want, but you must have an airspace around the insert jacket to make sure it doesn't overheat.
On the AL foil debate I'm siding with Pook (what's with the full sentences, punctuation & lack of "=" signs Pook?). For evidence I submit a simple experiment: Wrap a frozen burrito (or anything really, I just like burritos) in foil, shiny side out & throw it in a toaster oven (not convection). Don't do this if your really hungry, 'cause dinner will be a very long time cooking.
On the AL foil debate I'm siding with Pook (what's with the full sentences, punctuation & lack of "=" signs Pook?). For evidence I submit a simple experiment: Wrap a frozen burrito (or anything really, I just like burritos) in foil, shiny side out & throw it in a toaster oven (not convection). Don't do this if your really hungry, 'cause dinner will be a very long time cooking.
Really? in a toaster oven? I did this in mine & had a frozen burrito 30mins later.
Touche btuser. I'd be insulted if that weren't so funny.
Touche btuser. I'd be insulted if that weren't so funny.
Joe, Take a look at my install link below.. I freely admit that I went way overboard but I did the work myself and had the luxury of taking my time to achieve the most efficient install possible with an exterior masonry Chimney setup. It would be cost prohibitive to expect to pay an installer to go to such lengths. I must say I realized a significant increase in heat output from my insert. Most of the methods I used I got from other DIY installs I came upon surfing the many posts related in these forums..
Good luck with your install..
Link to my 2008 model install where most of the work was done:
https://www.hearth.com/talk/threads/27409/
Good luck with your install..
Link to my 2008 model install where most of the work was done:
https://www.hearth.com/talk/threads/27409/
bren582 said:
Thanks Bren. I've been thinking alot about this and I think I'm going to do something a little odd sounding and basic: I'm going to shove loose rockwool batts along the sides and then face them off with the heaviest duty aluminum foil I can find, attached to a grout line with a very thin line of quickset mortar.
If the installers don't do a block off plate, I think I'm simply going to shove loose bats up around the (insulated) liner pipe to prevent hot air from rising up the chimney as well as to keep the heat down around the insert.
It sounds really cheap, but it's also super basic and modifiable should I desire that in the future. And I think I'll get 98% of the benefit without alot of work, which would be hidden behind my surround trim anyway.
potato is getting baked with convective heat of oven air temp. side of wood stove is radiating heat horizontally & the foil reflects the radiant rays be4 it hits the wall. all convective heat off the woodstove will rise as hot air so foil on top aint gonna do much unless trying to bake a potato chimni & not have it dry outBrotherBart said:
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