The Hampton HI300 just doesn't seem to be throwing enough heat. What am I doing wrong?????????

[SherryAnn]

Before purchasing our Hampton HI300 wood insert, we had read many reviews singing it's praise. We have a brand new unit, in a house which is about 1700 sqare feet, 900 on the bottom and slightly less upstairs. In the room where the insert is, we both imagined, and heard from friends, that it would be like 85 degrees. It just isn't throwing as much heat as we thought. Let's eliminate the obvious, we are burning very seasoned wood. When I'm home constantly during the day, we can keep the downstairs at about 75, and I'm adding wood quite frequently. As soon as we have only red coals, it seems to cool right down. HELP Also, the handle that adjusts the air flow rattles, don't you think that for $4200 installed it should rattle like a tin can?

 

[edthedawg]

Let's assume the handle is supposed to rattle a little - you don't want it to bind, but it also should have some tactile feel to it, like it's actually doing something. If you feel it isn't providing you with any actual control to the air intake, then definitely contact your dealer / installer.

If you are getting the room to 75, you must be doing some things right. Where are you putting the air control? Are you running it wide open the whole time trying to get the fire hotter? If so - and you are never backing it down during the burn cycle - then that is the first place to look. It needs to be backed down after the first 10-15 minutes of hard burning or else you just exhaust the load.

Cooling right off when it goes to coals indicates all your heat is leaving the firebox too quickly. What is your chimney setup? Did you put in a blockoff plate? Full liner/cap? Assuming this is on an exterior wall of your house, did you insulate the liner?

And finally, what is your reasoning for claiming this is very seasoned wood? Not that it is or isn't - just curious if you've had it split & stacked for a year or more, used it in other stoves/fireplaces, have not had any hissing or steam/bubbling - or if you bought it and were told by the truck driver that "it's seasoned". I fell prey to that one this summer

Looking fwd to hearing your responses Good luck!

 

[stejus]

I have the same stove and can tell you about my one month of experience. The first two weeks I was using OAK that had been ageing 1.5 years. It got the HI300 up to 475 degrees (reading on the mantle top) very quickly and maintained that temp for hours when I backed down the air.

I ran out of the good aged OAK and now burning OAK that's about 7 months aged. I don't get nearly the same reading. I can get to 400 after leaving the air open much longer. I can't back it down as early or as quick so alot of the heat is going up the flue.

Make sure you have the blower turned on auto when burning with air. Fully dampered down (long slow burn) you should not use the blower.

My flex liner is not insulated and I have a makeshift soft blockoff plate. This will all be fixed in the spring.

Next burn season will be much better as I have next years wood stacked and the flex pipe will be insulated.

Good luck.

 

[Chettt]

How old is the house and what kind of windows and how much attic insulation do you have? If your room cools quickly it probably isn't the stove. Also do you have a temperature gauge for the front of the stove and how hot does it get? If it gets up to 500 degrees, the stove is doing its part.

 

[SherryAnn]

I'm starting to think I have installation problems.....here's the story.
I load it up in the morning when there's a nice bed of burning coal. I leave the door slightly open until everything inside is burning, then I close it up and leave the air fully open for another 15 mins or so, then I back it down halfway until for another few minutes, maybe 5-10, then almost completely shut for the remainder. I have the rutland thermometer on the front, i"ve tried it in several places, always seems to read the same. I have NEVER seen it get above 400 degrees, and that is rare. It is usually at 250 or 300, barely in the burn zone. Why doesn't it get hot? We have been running the fan on high constantly, and if we shut it off, we feel little heat at all.
The chimney is exterior, as you suggested, we had a full stainless steel liner installed, I am pretty sure there was no insulation. I'will call him and check (the installer)
We did get two chords of wood that definately were unseasoned (although he claimed it was) It would catch, we could tell it wasn't burning well. Now we have two chords more that are cracked on the sides, and burn nicely with no hissing or popping. Some pieces are nice and gray,(pieces on top?) others are not, but all are cracked. They feel pretty light and make that hollow sound if you drop on on a pile of them. Are we on the right track?
I can not tell you how happy I am to have some help, we have been VERY frustrated. I want to be running around in shorts like everyone else!1

 

[stejus]

I'm starting to think I have installation problems.....here's the story.
I load it up in the morning when there's a nice bed of burning coal. I leave the door slightly open until everything inside is burning, then I close it up and leave the air fully open for another 15 mins or so, then I back it down halfway until for another few minutes, maybe 5-10, then almost completely shut for the remainder. I have the rutland thermometer on the front, i"ve tried it in several places, always seems to read the same. I have NEVER seen it get above 400 degrees, and that is rare. It is usually at 250 or 300, barely in the burn zone. Why doesn't it get hot? We have been running the fan on high constantly, and if we shut it off, we feel little heat at all.
The chimney is exterior, as you suggested, we had a full stainless steel liner installed, I am pretty sure there was no insulation. I'will call him and check (the installer)
We did get two chords of wood that definately were unseasoned (although he claimed it was) It would catch, we could tell it wasn't burning well. Now we have two chords more that are cracked on the sides, and burn nicely with no hissing or popping. Some pieces are nice and gray,(pieces on top?) others are not, but all are cracked. They feel pretty light and make that hollow sound if you drop on on a pile of them. Are we on the right track?
I can not tell you how happy I am to have some help, we have been VERY frustrated. I want to be running around in shorts like everyone else!1

Move your Rutland on top of the mantle like shown in this pic. This pic was taken without my surround pieces attached. Make sure your blower is off. Get the reading right before you can close it down. With dry wood, you should be getting close to 500 degrees and your secondary burn should be dancing around.

If you are not getting this type of reading, you may have too much draft in your chimney or you're loosing a lot of heat up the clay liner. I didn't see you mention a block off plate. If you don't have one, just stuff some insulation inbetween the liner and damper plate (known as soft blockoff plate). Look into getting that sealed shut and insulated later this spring.

 

[woodgeek]

Perhaps you are shutting it down early or not really stuffing the box? I tend to look at these things mathematically. If you know how much wood you loading in, figure ~4,000 BTUs per pound total heat output, divided by the length of your burns to get average BTU/hr. If that BTU/hr is anywhere close to the full demand of your house (assuming you have an open plan, open doors and heat rises) then you will def have a hard time getting to 85F! You can always close some doors to make your living room a sauna when the mood strikes. IF your estimated output, however, is well above what your house requires, then indeed, you are missing some BTUs.

So, the other part is estimating your house BTU demand....
First, figure the nominal output of your central heater (usually on a label). IF you can time the on/off cycles of your furnace when the wood stove is cold (and hopefully when the sun is not shining in the windows), you can figure your demand at a given outside temp.

For example, my boiler puts out 110,000 BTU/hr, and runs about 40% of the time when its in the teens outside, so my demand is 44,000 BTU/hr. I would need to burn wood at an average rate of 11 lbs/hour just to keep up (probably more like 15 lbs/hr with my low eff POS stove).

Hope this helps....

 

[cocey2002]

I worry with the statements that your Rutland should be reading over 400 close to 500. If you get to 450-500 I think your probably overfiring. 375-400 IMO is about as high as you want to go. I could be wrong but at 400 my tubes were red. And with my experience with this stove you have to stuff the box with as much wood as possible before shutting the air down. I stack larger spilts on the bottom and then smaller ones under the tubes. I can tell you that I get my livingroom where the stoves at up to 83-85 degrees. Upstairs stays between 69-73. Two story house 2300sqft.

 

[edthedawg]

I'm starting to think I have installation problems.....here's the story.
I load it up in the morning when there's a nice bed of burning coal. I leave the door slightly open until everything inside is burning, then I close it up and leave the air fully open for another 15 mins or so, then I back it down halfway until for another few minutes, maybe 5-10, then almost completely shut for the remainder. I have the rutland thermometer on the front, i"ve tried it in several places, always seems to read the same. I have NEVER seen it get above 400 degrees, and that is rare. It is usually at 250 or 300, barely in the burn zone. Why doesn't it get hot? We have been running the fan on high constantly, and if we shut it off, we feel little heat at all.
The chimney is exterior, as you suggested, we had a full stainless steel liner installed, I am pretty sure there was no insulation. I'will call him and check (the installer)
We did get two chords of wood that definately were unseasoned (although he claimed it was) It would catch, we could tell it wasn't burning well. Now we have two chords more that are cracked on the sides, and burn nicely with no hissing or popping. Some pieces are nice and gray,(pieces on top?) others are not, but all are cracked. They feel pretty light and make that hollow sound if you drop on on a pile of them. Are we on the right track?
I can not tell you how happy I am to have some help, we have been VERY frustrated. I want to be running around in shorts like everyone else!1

I can feel the frustration here! :grrr: To answer your (highlighted) question - you're making plenty of heat - it's all going up your flue!!

Seriously - your wood and burn practices do sound good. A couple follow-on questions that still need addressing:

You are getting good secondary burns, right? or do they disappear after just a few minutes?

How tall is that chimney/liner? if it's really tall, you may want to look into some way to add a flue damper to your system - possibly a tall order for an insert...

Have you looked up into the top of your stove and observed the tubes baffle plate, etc are intact, in proper place, etc? (someone experienced with Hi300 pls step in here) If you have a baffle plate that has shifted fwd, that will let heat escape right up the flue, as opposed to keeping those high-temp combustion gases lingering a little longer in the stove (thereby heating IT up more).

Good luck SherryAnn!

 

[wtb1]

I have a question that pertains to the thread. Last week I had a Hampton i300 installed with a full SS liner. I have had several fires but I have not gotten the heat I thought I would. I get the fire hot enough to get secondaries but they seem to stop after a few minutes if I shut the air down completely. As I was coming home yesterday I noticed that I still had my old chimney topper which is basically used to keep out the birds and has a solid "roof" to keep out the rain. There is no damper per se to restrict the draft.

Do I need to put in a different top to help slow the draft some and therefore maintain more heat in the firebox? I called the guys who installed it and they said what I had should be fine.

Thought?

 

[stejus]

I worry with the statements that your Rutland should be reading over 400 close to 500. If you get to 450-500 I think your probably overfiring. 375-400 IMO is about as high as you want to go. I could be wrong but at 400 my tubes were red. And with my experience with this stove you have to stuff the box with as much wood as possible before shutting the air down. I stack larger spilts on the bottom and then smaller ones under the tubes. I can tell you that I get my livingroom where the stoves at up to 83-85 degrees. Upstairs stays between 69-73. Two story house 2300sqft.

I agree with the loading up the HI300 and then shutting down the air. If you don't load it up, you will get less heat btu's. To get the most heat, I do the same as cocey2002. Rake as many of the coals forward. Lay three large splits on the bottom, two smaller splits on top of these, and then fill the remaining with small rounds. Basically you want to stuff as much wood in there as you can. If you do this and run it 1/2 shut down, you should get around 5 hours of good heat. If you totally shut down as I do at around 9:00PM, I still have a good coal bed in the back of the stove in the morning around 6:00AM.

 

[SherryAnn]

cocey2002, How often do you add wood. I stuffed mine at 10:30 this morning, when I came back at 2:40, the house was cold and all there was in the stove was red coal covered in ash, i couldn't see the coal until I moved it around. I have to me home to keep the house warm.

I loaded it up, let it run 1/2 hour wide open and thermometer still reads only 250. Could that be broken too? I'm thinking there's a hex on me!

I have a call into my installer, I don't know much about the installation, I'm embarrased to admit, because I thought I'd hired a professional who would do it right. Silly me for trusting. I should have known when it wasn't level when first installed that something was up, we couldn't leave the door ajar without it falling open. On the receipt all it said was 'installation with a 6" stainless steel liner system $1200. It took him about 3 hours to install. That's a good pay rate! I'm scared we got rooked! As for looking up into the stove, everything looks fine. I think the Chimney is about 30 feet. I am so new at this and there seem to be so many variables. Th

 

[stejus]

cocey2002, How often do you add wood. I stuffed mine at 10:30 this morning, when I came back at 2:40, the house was cold and all there was in the stove was red coal covered in ash, i couldn't see the coal until I moved it around. I have to me home to keep the house warm.

I loaded it up, let it run 1/2 hour wide open and thermometer still reads only 250. Could that be broken too? I'm thinking there's a hex on me!

I have a call into my installer, I don't know much about the installation, I'm embarrased to admit, because I thought I'd hired a professional who would do it right. Silly me for trusting. I should have known when it wasn't level when first installed that something was up, we couldn't leave the door ajar without it falling open. On the receipt all it said was 'installation with a 6" stainless steel liner system $1200. It took him about 3 hours to install. That's a good pay rate! I'm scared we got rooked! As for looking up into the stove, everything looks fine. I think the Chimney is about 30 feet. I am so new at this and there seem to be so many variables. Th

You may be overfiring if you let it run wide open for 1/2 hour. I have the benefit of seeing my stove pipe because my surround peices are not on yet (due to missing part). If I let it go longer than 10 or 15 minutes, my flex liner starts to get red. You should start shutting down in stages as soon as all wood has started to char and flame. The sooner you close it down, the more heat builds it the stove. Leaving it run wide open this long runs the risk of overfiring and heat up your liner and less sustained heat.

Questions: How cold is it where you are? How open/closed is your floor plan? How high are your ceilings? What is the temp at the ceiling level vs seat level. What type of wood are you burning?

I just installed a ceiling fan in my kitchen because the ceiling was 78/80 degrees.

 

[edthedawg]

You need the installer to come out and/or talk some more about the installation. I'm very willing to bet you didn't get a blockoff plate above the firebox - it's extra work, you can't see it, and it's just easier for any installer not to do. Having one is highly recommended. And with an exterior chimney, it should be an insulated liner - not just a bare SS tube in your masonry flue.

The bigger thing (IMO) is to try and get a damper into that flue right above the stove. Maybe there is some way they can put a long arm on it thru the front surround plate, or maybe Hampton sells a kit you could use? 30 feet of 6" liner - that's a LOT of suction pulling the heat out of the box. I have only a little more than that and I'm doomed without my damper. (Edit: see Stejus' comments above re: glowing red liner. He's describing doing what you are - sending all the heat right up the flue.)

Not calling your installer bad or lazy - a lot of times these guys think they're doing it right but they just don't really know better. But you have 3 things now (insulation, blockoff plate, and flue damper) that you really need to discuss... And don't accept "they never need that!" for an answer - if you weren't having problems, you wouldn't be banging on the door, right??

At the very least, get your Professional Installer to come out and get your insert thermometer to 500*F. (without using dynamite)

 

[SherryAnn]

You may be overfiring if you let it run wide open for 1/2 hour. I have the benefit of seeing my stove pipe because my surround peices are not on yet (due to missing part). If I let it go longer than 10 or 15 minutes, my flex liner starts to get red. You should start shutting down in stages as soon as all wood has started to char and flame. The sooner you close it down, the more heat builds it the stove. Leaving it run wide open this long runs the risk of overfiring and heat up your liner and less sustained heat.

Questions: How cold is it where you are? How open/closed is your floor plan? How high are your ceilings? What is the temp at the ceiling level vs seat level. What type of wood are you burning?

I just installed a ceiling fan in my kitchen because the ceiling was 78/80 degrees.

I'll try closing it down sooner. We live not far from you I'm assuming, since I am in Rhode Island. So we have similar weather. We have normal 8 foot ceilings. The fireplace is in the left wall of the house in the back. There's an open staircase up the middle. Living room, family room, and dining room are all very open, with 5-6 foot doorways, the heat definately goes up the stairs quite well. Maybe we are so open that the heat disperses quickly which is why it doesn't seem very hot in the room where the insert is. I am pretty sure it's all oak and maple. I have so much to learn.....I know it isn't pine......

 

[SherryAnn]

You need the installer to come out and/or talk some more about the installation. I'm very willing to bet you didn't get a blockoff plate above the firebox - it's extra work, you can't see it, and it's just easier for any installer not to do. Having one is highly recommended. And with an exterior chimney, it should be an insulated liner - not just a bare SS tube in your masonry flue.

The bigger thing (IMO) is to try and get a damper into that flue right above the stove. Maybe there is some way they can put a long arm on it thru the front surround plate, or maybe Hampton sells a kit you could use? 30 feet of 6" liner - that's a LOT of suction pulling the heat out of the box. I have only a little more than that and I'm doomed without my damper. (Edit: see Stejus' comments above re: glowing red liner. He's describing doing what you are - sending all the heat right up the flue.)

Not calling your installer bad or lazy - a lot of times these guys think they're doing it right but they just don't really know better. But you have 3 things now (insulation, blockoff plate, and flue damper) that you really need to discuss... And don't accept "they never need that!" for an answer - if you weren't having problems, you wouldn't be banging on the door, right??

At the very least, get your Professional Installer to come out and get your insert thermometer to 500*F. (without using dynamite)

I told him (the installer) that the thermometer wasn't registering very high, he said I should call hampton and ask them about a thermometer, he knew nothing about it. He doesn't actually burn wood in his house, maybe that should have been my first question when hiring someone. I did call hampton and they told me that they don't work on this type stove, so not to bother. he said they belong on the pipe of a wood stove. Why am I getting such ridiculous answers?????????? The people at Hampton DON't seem to want to talk customers, the one conversation I had was nothing compared to the help you all have given me. I even tried a few emails. When they get back to you, maybe a week later, they give a short answer and direct you to your installer.

So how often should I be adding wood? Now I've been up and running full force for 1 1/2 hours and I already have absolutely no flames at all in the stove. This is when I want to shove more wood in, but it seems like I've lost flames too soon.........

 

[SherryAnn]

I take that back, when I got down on the floor and looked in the back of the stove, I have some blue slowly dancing flames in the rear of the firebox. Is this secondary burn?

 

[stejus]

You may be overfiring if you let it run wide open for 1/2 hour. I have the benefit of seeing my stove pipe because my surround peices are not on yet (due to missing part). If I let it go longer than 10 or 15 minutes, my flex liner starts to get red. You should start shutting down in stages as soon as all wood has started to char and flame. The sooner you close it down, the more heat builds it the stove. Leaving it run wide open this long runs the risk of overfiring and heat up your liner and less sustained heat.

Questions: How cold is it where you are? How open/closed is your floor plan? How high are your ceilings? What is the temp at the ceiling level vs seat level. What type of wood are you burning?

I just installed a ceiling fan in my kitchen because the ceiling was 78/80 degrees.

I'll try closing it down sooner. We live not far from you I'm assuming, since I am in Rhode Island. So we have similar weather. We have normal 8 foot ceilings. The fireplace is in the left wall of the house in the back. There's an open staircase up the middle. Living room, family room, and dining room are all very open, with 5-6 foot doorways, the heat definately goes up the stairs quite well. Maybe we are so open that the heat disperses quickly which is why it doesn't seem very hot in the room where the insert is. I am pretty sure it's all oak and maple. I have so much to learn.....I know it isn't pine......

Just for giggles, get a temp reading as close to the ceiling as possible. You can have 10 to 15 degree temp difference and adding a ceiling fan may help. I just installed mine over the weekend and it made a big difference. I managed to get the room to 82 degrees (at the ceiling level) once. I loose a lot of heat to the stairs, like you, that lead to the upstairs bedrooms. So the only way to get back some of the heat is to move it off the ceilings.

Don't get discouraged. It's really cold out too. When temps rise just a little, say 20 to 25 overnight and 30 to 35 during the day, you will notice a big difference. Trying to heat a house when the temps are around 0 in the morning is tough. Some folks get up in the middle of the night to reload to keep the heat going. I don't and it's 60 degrees in the house (stove room). It takes a while to recover to 75, sometimes by late morning or early afternoon. Once we get back to normal temperatures, you'll see big difference in the amount of heat in your house.

 

[edthedawg]

Running full force? wide open? if so - not good!

Another thing i didn't pick up on fully before - you exhausted a full load in 4 hours from load to cold. That's way too fast. It really sounds like you have good wood here (and it would be helpful if you can confirm you are NOT getting hissing or water bubbles from the ends of your splits!) You are just getting way too much draft and need to slow that baby down.

So here's my thought - a couple of them in fact:

1 - try backing it down sooner, and get yourself to about ~1/8 open on the primary within 15 minutes, and see what that gets you. Don't shut it all the way - just leave it there - you might be surprised. You need to aim AWAY from your current experiences (short-lived, overdrafting, hot fires w/ all heat going right up the flue) and aim FOR longer lasting, more restricted, better-contained fires. Raging tall flames? NO. Lazy secondaries dancing on the top of your firebox? BINGO. Look up "secondary burn" on youtube - lots of folks post vids of good secondaries.

2 - suck it up and find yourself a new installer. This area is rife with them - someone with some solid experience needs to look at this thing. Sorry you may have invested in the wrong horse here, but you DO have a good machine regardless - now you just need to find the right mechanic to tune it up and make it purr for you.

 

[cocey2002]

Ok- here is what I typically do when I get home from work at 3:00. Stuff as much wood in and run wide open for about an hour. Throw a couple more splits in and then wait about 20 minutes and close a quarter of the way. Wait another hour and then a few more small splits and close to about 35%. After about 3 hours my downstairs is over 80 degrees. I then let it get down to a nice coal bed and then load it up around 9:00 and run it half way. I wake up at 4:00 am and I have a few coals left to stuff her before I go to work. For longer burn time I put the splits in horizontal. Faster quick fires vertical. I run the fan on high through the switch. It usually kicks on around 200 degrees.
On colder nights I do the same but I turn the fan off until the temps are over 350. At that point I turn the fan on high and then cut the air to around 40%.

 

[stejus]

I have a question that pertains to the thread. Last week I had a Hampton i300 installed with a full SS liner. I have had several fires but I have not gotten the heat I thought I would. I get the fire hot enough to get secondaries but they seem to stop after a few minutes if I shut the air down completely. As I was coming home yesterday I noticed that I still had my old chimney topper which is basically used to keep out the birds and has a solid "roof" to keep out the rain. There is no damper per se to restrict the draft.

Do I need to put in a different top to help slow the draft some and therefore maintain more heat in the firebox? I called the guys who installed it and they said what I had should be fine.

Thought?

I would say no and here's the reason. My sweep recommended putting on a hood as you described. He doesn't like the caps (the one I have) because they tend to clog up and reduce draft. I only went with the cap because it came free with the liner and I know the sweep will be back in the sring to insulate the liner. At that point, I am taking my cap off and installing a full hood over the entire chimney (two flues).

If you shut it down too soon, this will happen. You should shut down in 3 or 4 stages. For my overnight burn, I let it rip for about 15 minutes and start to close it down in 4 stages to a complete shut down in about a half hour to 45 minutes.

Do you have a block off plate or insulation around your damper where the flex liner passes through?

Is your chimney capped at the top of the clay liner?

 

[iceman]

ok many good suggestions here but lets back up

stove is not throwing heat because ....... everything is going up your chimney, exterior chiminey , no block off plate .. might not be insulated all bad
also your wood isn't that seasoned some of it may be but majority prolly isn't..... not good but can be dealt with
question... when your stove is barely burning can you feel cool air from behind it? when the stove is not burning (no fire) do you feel cold air from the back or around the sides? if so its prolly coming down your chimney... not good but block off plate will help/stop it
now place your thermometer where the pic in the earlier post has it... get a fire going and leave the air till you get a good fire going the go to half way... do this with only a couple of splits ... leave it there and monitor the temp don't worry about the stove temp as it won't overfire.. but let it go until its all hot coals... then load up the stove and repeat but after getting the stove hot close it down gently don't leave the stove at the half way point forever watch the fire and you will be able to tell when to start closing it down.. my stove hits 700 almost everyday for a little bit so don't panic

 

[burntime]

I agree, problem with wood. I have the same stove, insulated liner in interior chimney. I have yet to hit 400. 250 to 350 is fine, remember you are not measuring the firebox, rather the air coming out! You will find the sweet spot on your control to find out how far you can choke it down. Mine without the insuated liner was closed and then opened an inch to inch and a half. Now that I insulated the liner and block off plate, good wood, got it dialed, I close it all the way down. You will find the sweet spot will change with the tempature of the outdoors. You will be able to damper it down more the colder it is. This will make sense in a month or two of use. Go buy some expensive grocery store wood. I bet you get good and hot. You will need 2 bundles to fill it up. You will be able to choke it down to the sweet spot anytime your top reads 200 or better +/- so as you learn the stove it will be easy! This is assuming your wood is properly seasoned. Good luck!

 

[cocey2002]

Just a quick reminder that our Hampton will not measure temps very well. Most of us put the Rutlind on the shelf and aim for over 300 degrees. At 300 degrees you are probably around 550 degrees measured on other stoves.

 

[SherryAnn]

Iceman, See this is the problem, my thermometer NEVER reads over 300, I think we got it to 350 once by repeatedly stacking it as soon as we had only red coals. If I did that all the time, I'd have to put wood in it every two hours or so. Then I end up at the end of the day with a stove full of semi hot coals that need to burn down, which takes hours and the whole house gets cold. Maybe my thermometer is broken????????? I have that same one in the picture and that is where I have kept it all day, previously I had it on the door. Doesn't really matter, always reads the same almost nothing! There is definately something wrong. The installer hasn't called me back yet. There is a huge space between the unit and the fireplace at the top, I know there is no way around this since it is made from rocks which are uneven. I asked him if any air would come in through the space and he said it was sealed off with cement, but I have no idea where. Is this what you are referring to? Again thanks so much. I've really spent most of the day trying to figure this out, actually most of the past six weeks! I'd like to think I'm faily intelligent, it's only FIRE, so I do think something is wrong.