Under size or over size stove in a home?

[wmbriano2grad]

I have heard that it is better to under size a stove in your home than oversize b/c your stove will never burn as hot as it should if you oversize (unless you want to bake!). On the other hand, you have to make sure you don't overfire a smaller stove to get more heat than is intended.

If my home is about 1800 sf, fairly tight and insulated, two floors, in VA, will I regret going with a Jotul F3 rather than the F400? the room the stove is in is the room we sit in most of the time to watch tv, etc. That's a consideration b/c we want to heat the house w/o being smoked out of the living room.

I think I would rather have the f400, but having a hard time finding a used one that hasn't already been sold.

Thanks!

 

[wg_bent]

I have a stove more similar in size to the 3cb than the 400 and mine heats my 2200 sqft home reasonably well. My stove is in the same room as the TV. My wife thinks the stove could be bigger, and I agree, but only because I'd like to get more wood in it rather than make it hotter.

In Virginia...I'd say the 3cb would be enough, but there are a lot of factors involved.

Layout of the house is one of the primary issues. Ceiling fans?

One other thing to consider here is that you won't perfectly heat a house with one stove, but rather heat 1-3 rooms pretty well, and the upstairs will likely be cooler. We find that to be perfect for our needs and if on super cold days we have to kick on the oil burner, then the stove is sized just right. In Virginia, you won't get days that are as cold as ours in NY, so you may never see your central heat kick on. I know mine doesn't until temps drop below 10. Below 10, the stove begins loosing ground.

 

[suematteva]

We oversized...

1900 sqf house, the mansfield is good upto 2500-3000 acording to brochures..We are well insulated and in Quebec.

Burn habits & times, climate, install room (centralized?), is going to be primary heat, climate, etc all influence performance.

We are glad we went bigger.

 

[Corey]

Looks like you are on the right track and I'm sure you will get some pretty good advice here, too.

IMHO - you have to look at how you will use the stove, too.

If you plan to keep a fire burning all the time, or use it as occasional supplimentary heat, then a stove on the smaller end of what your home needs will probably be adequate. In my case, I let the fire go out during the day because no one is home and try to use the stove for the main source of house heat. So I am looking for a big blast of heat in the evening to get everything back up to temp. Consequently, I have a stove that is on the larger end of what my home really needs.

It's also a good idea to consider your home location and any special circumstances. Are you down in a valley, up on a wind-blown hill, have abnormally low or high temps for your area. If so, you may want to take that into account when sizing a stove.

Corey

 

[babalu87]

Bigger
You can crack open a window if it gets too hot or just let it go out.

 

[elkimmeg]

Not stated here is manufactures claims are over stated. Take a 1/3 off and this is what to expect Do you know how hard it is to manitain a fire the constantly puts out the maxium range? Higher wood consumption more loading and fiddling with controls. Wood not as dry as it should be. In the real world it is easier to get a larger stove operation at 70% than a smaller one near 100%. Then there is the wood box size factor, smaller stoves do not have the vollume to burn as long.. There is a good arguement that is best to run a smaller stove hoter more effecient,but once you chop pf 33% for real world conditions. (These stoves are tested in a labatory)
chimney draft issues I would recomend one size up. I do not know you layout the openess and your planned usage. or wood supply moisture content. Actually either stove will work. I just swapped out a stove to get 18% more capacity. I'm in New England. burning two cat stoves 24/7 I like smokeless top loading easier to fill the fire box I like the thermotacially controled secondary air for constant heat range over a long period of time. I like the cat for extracting more heat and cleaner burning I like knowing I an using one of the cleanest burning wood stove ever tested by the EPA. I like my stoves knowing it supports American Foundry and Manufacturing Jobs right here in good old USA

 

[RoosterBoy]

good man elk i agree support good us jobs and buy American clean burning. i went with none cat because i did not want the stove company to go out of business in 5 years then i cant buy cat's for my stove but mine is clean burning 2.6gph

thanks
Jason

 

[Corie]

If you want to give me a basic floor plan of your house, along with the insulation amount and construction materials I could give you a pretty godo estimate of how many BTU/hr you're going to need.

 

[jjbaer]

Here's part of one I posted on another page in the forum. Hope it helps size a stove:


Sizing tips: look at your energy consumed to heat your house in your coldest month and convert this to BTU’s. Divide by the number of days in the month and divide again by 24 hrs. Then multiply this by about 0.9 to get a rough idea of the average number of BTU’s required to heat your home per hour during your coldest month. Then, look at your room size as compared to your total house size and determine what fraction of the total BTU’s required for the entire house are required for the stove room itself. Then determine how many more BTU's/hr you need to put into this room and your ability to distribute these added BTU's elsewhere in your home without overheating the room the stove is located in.

Example: Note: this is a natural gas example but you can do a similar conversion if you heat with propane or electricity. Let's assume you heat your home (70 F average for instance but it really doesn't matter) and your hot water, with natural gas and your Dec gas bill shows 200 CCF consumed. 200 CCF is 20,000 cubic feet of gas (there are 100 cubic feet per CCF). Assume your hot water consumes 15% of this so the other 85% (17,000 cubic feet) is consumed by your furnace for heating your home. Each cubic foot of natural gas has about 1,000 BTU’s in it so 17,000 cubic feet is 17,000,000 BTU’s consumed in Dec. Divide this by 30 days in Dec and again by 24 hrs in a day and you get 23,611 BTU’s of gas consumed (at the furnace burner) each hour to heat your home! Now multiply this by about 0.9 because only about 90% of this heat is delivered through your duct work to your rooms with the rest being vented to the outside via exhaust. This gives about 21,249 BTU’s per hour being required to heat your home to 70 F. NOTE: this 90% figure assumes you have a high efficiency furnace. Use a lower figure if you have a more inefficient furnace.

Now let’s say your home is 1800 sq ft in size and the room you want to put this stove in is 300 sq ft. If 21,249 BTU’s are required to heat your entire 1,800 sq ft home, then the BTU’s required for this 300 sq ft room are only 300/1800 times the 21,249. That is, only 3,541 BTU’s/hr are required to heat this room! This surprises most people because they think in terms of 40,000 BTU/hr and larger stoves when in fact, for this example, only about 3,500 BTU’s/hr are required to maintain this room at 70F.

Now that hard part: you need to decide that if you put significantly more BTU’s into this room than the 3,500 BTU’s/hr calculated, will you be able to distribute these added BTU’s to other rooms in your house without significantly overheating the stove room? If you think you can distribute these additional BTU's and you want to heat your entire home, you need about 21,249 BTU/hr on average output from your wood stove. If you don’t want to overfire your stove, on average you’re looking at needing approximately a 50,000 BTU/hr stove so that your average output is about 25,000 BTU/hr or so (which is approximately your heating requirement of about 21,000 BTU/HR).

If not, then a small stove is in order. You can try to distribute heat by turning on the circulating fan on your furnace or by natural convection if you have an “open design” in your home or by using a blower motor on your stove, etc. or you may simply pour more BTU’s into this room, thus elevating it above 70F and hope that residual heat is distributed to other rooms. This is where the “trial and error” comes into play and hopefully you find the happy median where your stove room is warm, but not too warm while maximizing the warmth of the other rooms.

hope this helps

 

[blthomas]

That's alot of math.... :gulp:

But that's some great info. Even though several folks spoke up about the OSburn I'm considering, I need to sit down and do this math over a beer.

Make sure I have my situation covered before I make a purchase I regret.

 

[jjbaer]

Almost any stove will provide more than enough heat for one medium sized room that's even moderately insulated. What normally happens is that when the room the stove is in is nice and warm, the other rooms are generally too cold. So we compensate and overheat the stove room and try to move the extra hot air to other rooms.

 

[Wyatt]

FYI - Carpniels has a used F400 Castine listed in the For Sale section of this forum!

 

[fastrac]

I can tell you some thing I tell my customers

Imagine you have a stereo in the romm the stove is going to be installed in.

then imagine you want to hear the stereo in the entire house ,But there is only one speaker and its in where the stove is.

Now imagine in order to hear the stereo in other parts of the house, What would the volume level be in the room with a stove? could you still be in the room, Would the room still be useable

I always feel the mistake is when you grossley oversize a stove and your not able to burn clean

But the best people to ask are folks who have done it allready

More and more folks are coming in these day not looking for the biggest (as there freind has an oversized stove and they cant stay in the room ) and they really want something to do the job and struggle with the load

 

[tradergordo]

Its been mentioned - but I think house layout is possibly the most important factor really. A lot of people on these forums believe the manufacturers overstate the estimates of square footage their stoves can heat - but I do not believe this is true.

Manufactures should (and most do) give a big range - that range has to cover a huge number of variables including climate, insulation, and house layout to name a few. This is my first year heating with wood so I don't have the experience that others do, but my Vermont Castings Dutchwest Large, according to VC's sales literature, is only rated to heat 1000-2400 sq. ft. So far, I have been heating my ENTIRE house, 2800 sq ft with this stove. Now we haven't had any sub-zero weather yet, so I don't know what to expect going forward, but we have had low 30's and the entire house, every room, has been comfortable, I can easily get the upstairs bedrooms to 75F. The stove is on the 1st floor, the house is a modern open floor plan house with good insulation and vaulted ceiling in the family room where the stove is located. Ceiling fan at the top of that room. Upstairs generally gets about 2 degrees HOTTER than downstairs where the stove is. I am using the stove exclusively for heat, no furnace, and no furnace blower.

FYI, regarding castiron's calculation comments. That is a good starting point, but I question his ".9" factor - this is supposed to compensate for the efficiency of your furnace - but you should get the furnace number from the label on your furnace instead of using .9 (many people have more like .8) or try to get the real number somewhere else. But there is an even bigger fudge factor - and that is the loss of efficiency to the ductwork - which many believe to be as high as 30-40%. This is also why most here on hearth.com agree that it is generally NOT a good idea to try to circulate your air using the HVAC ducts and blowers (this has been discussed here before). The HVAC blower is probably using 300 watts of power if not more, and is terribly inefficient (electric bill goes up with only sub-par heat distribution).

Also castiron's assumption of 15% for the hot water heater is probably not very accurate. Just look at a couple summer bills and you can get a pretty exact figure for how much goes to hot water, cooking, & clothes dryer combined.

If you go to the bottom of my web page you can see how I approximated the amount of wood I would need this year, which is a very similar calculation. But the truth is there are so many variables that it is pretty hard to be precise.

 

[jjbaer]

Tradergordo,

My calculation is a good approximation as to what is required to heat a house. For my own calculation, I did go to my summer bills (where all the gas consumed was for other than heating purposes) and I used that gas estimate and subtracted it from the Dec bill to see what amount of natural gas was consumed at the burner head in Dec for heating. In this manner I was able to isolate the amount of natural gas that was used only for heating. And I DID caveat my use of 0.9 to figure in furnace loss and duct loss. My furnace is 7 yrs old and it has an efficiency of 95%. My ducts (which run through my crawlspace) are taped and heavily insulated so I figured that there's a 5% loss in the furnace and 5% loss in the ducts, and thus I assumed that 90% of what's consumed at the furnace actually gets distributed to the rest of the house. I also stated that if a person has a less efficient furnace then use a lower number but my methodology IS much better than ANY other approximation I've seen anywhere in this forum. Your comment that "But there is an even bigger fudge factor - and that is the loss of efficiency to the duct work - which many believe to be as high as 30-40%" may actually not be applicable for some people. Many people who have their furnace in the basement also heat the basement in which case duct losses actually don't count (in which case you only have to figure in furnace efficiency) because the escaping heat from these ducts (which run entirely within the house) actually helps heat the house! In my case they escaped to the crawlspace so I deducted them.

Also, your comment of "The HVAC blower is probably using 300 watts of power if not more, and is terribly inefficient (electric bill goes up with only sub-par heat distribution)" isn't entirely true. As I stated, my furnace is 7 yrs old and at that time I got the variable speed motor which consumes FAR less electricity than does a normal motor. Use of these motors is becoming a far more common-place occurrence and the wattage consumed in fan-only mode is only about 100 watts. So, when I fire-up my stove between 5 PM - midnight, I run this blower about 6 of these hrs. That's about 600 watt-hours a night which is about 6 cents per night to operate this blower at a 10 cent per KW-HR rate. This is a whopping $1.80 per month so for me it's not much of a consideration. And you're correct that use of the blower may or may not help some people. In my case it heats the kitchen, dining room and adjacent family room and gives some, but not much heat to the bedrooms...but then again, I have a ranch style layout.


I did enjoy your post and link!

 

[tradergordo]

Castiron - a furnace with 95% efficiency is pretty impressive, and only 100 watts for the blower is also impressive but I don't know how big your house is. I haven't looked at furnaces in years, so I have no idea what average is these days. Mine is 7 years old, and its a only 80% but hopefully I'll never have to use it again! As for the loss to ductwork - I kind of disagree with you about heat seeping out into the house not being "lost" if most of that heat is seeping into non living areas (such as the INTERIOR of your walls or a rarely used basement or crawlspace). I got that 30-40% loss of efficiency figure from this Hearth & Home article:


(broken link removed to http://www.omni-test.com/Publications/Efficiency_article.pdf)

"Some surprising facts are
revealed when energy usage on an
overall home scale or on a national
scale is considered. When all
aspects of heating appliance use
are taken into consideration, wood
stoves, pellet stoves, masonry heaters
and fireplace inserts replace more fossil
fuel energy through their use than
the comparison of appliance efficiencies
alone would suggest. This is, in
part, because most traditional gas and
oil furnaces, which are the mainstays
of home heating in the United States,
have lower overall effective efficiencies
than is obvious at first glance.

"Without going into detailed and
messy calculations, here’s why: First,
studies have shown that there is typically
30 to 40 percent efficiency loss
due to duct work for forced air furnaces.
Second, furnaces with draft hoods
induce a much higher air exchange rate
in a home, bringing in more cold,
unheated air than airtight wood heaters.
Third, most wood heaters are considered
zone heaters, while gas and oil furnaces
are centralized. It is generally
accepted that zone heaters are, in practice,
more efficient than centralized furnaces
since only specific areas during
specific times are heated when zone
heaters are utilized, thus avoiding energy
waste. In all fairness, it must be noted
that new technology furnaces and home
designs with furnaces can also be quite
energy efficient. However, the overwhelming
majority of homes and furnaces
do not fall into that category."

 

[tradergordo]

furnaces with draft hoods
induce a much higher air exchange rate
in a home, bringing in more cold,
unheated air than airtight wood heaters.[/b]

On another note - what do other wood burners do, if anything, with their furnace draft hoods (that's a chimney in layman's terms) if you don't use your furnace? I hadn't really thought about this before - should I disable the furance (an obvious important step) then stuff some insulation in that thing and seal it up? Or does it not really matter? I think that vent is shared by the natural gas hot water heater. No idea if cold air would downdraft from that thing? Even if it is shared with the hot water heater I could seal off the part connected to the furnace.

 

[jjbaer]

Hi Tradergordo


You said: "Castiron - a furnace with 95% efficiency is pretty impressive, and only 100 watts for the blower is also impressive but I don’t know how big your house is. I haven’t looked at furnaces in years, so I have no idea what average is these days. Mine is 7 years old, and its a only 80% but hopefully I’ll never have to use it again! As for the loss to ductwork - I kind of disagree with you about heat seeping out into the house not being “lost” if most of that heat is seeping into non living areas (such as the INTERIOR of your walls or a rarely used basement or crawlspace). "

Comment: my furnace is a Carrier Weather Maker Infinity Model 58MVP bought in Nov 1998. The nearest link carrier has to this model now is the 58MVB located here:

(broken link removed)

which is now 96% efficient and I think mine is 95% efficient.

I would agree with the ductwork analogy where most people lose 30% but hot air rises and some of this will find it's way to the 1st floor level. That said, you're right that there's a lot to be gained. A roll of Aluminized duct tape and the 2 hrs work it takes to tape duct joints will save most people a boat load of cash. Anyone can do it. I taped mine in my crawlspace and the ducts are insulated and the side-pipes carrying heat to the rooms above also have insulation. So, combining my 95% or higher efficient furnace with taped and insulated ducts lets me use 10% loss (i.e., 90% efficiency) for heat delivered. Also, Carrier also had (can't find it now) a slide showing the fan consumed only 60W when operating at low speed. I was being conservative when I used 100W....think it's a bit lower.

As far as "furnaces with draft hoods induce a much higher air exchange rate in a home, bringing in more cold, unheated air than airtight wood heaters."

Comment: my 7 yr old Carrier uses outside air for combustion and vents exhaust through a PVC pipe, also to the outside. The furnace is so efficient that the exhaust gas is only about 100F hence it can be vented using PVC. Based on these, I don't think there's much of any induced draft...at least none that I notice.

I agree with the comment in your article of "In all fairness, it must be noted that new technology furnaces and home
designs with furnaces can also be quite energy efficient. However, the overwhelming majority of homes and furnaces
do not fall into that category.”

Comment: I think the min efficiency for furnaces is still 80% however, depending on gas prices, there's almost as much $ to be saved in getting a high-efficiency variable speed motor (versus a standard motor) as compared to going from an 80% to 93% efficiency furnace.....that is, the electricity savings by using a DC variable speed motor can often outweigh the gas saved in going from an 80% furnace to a 93% furnace....depends on the price of gas vs electricity. I opted to get both the 95% furnace and the variable speed motor.

As far as my house: 1-story ranch, 1600 sq ft, 3BR, 1.5 Baths, LR, FR, DR, Kitchen, 1/4 basement and 3/4 crawl space. R-15 in walls, about R-45 in attic and R-19 on underside of floors in the crawlspace. I live 10 miles south of Dayton Ohio and my natural gas bills (hot water AND heating combined) were as follows (Note: I'm NOT on level billing...this was the true gas cost for these months...my May-Sep bills are $28/mo).

Dec 2005 $147
Jan 2006 $98
Feb 2006 $97


Regards

 

[jjbaer]

furnaces with draft hoods
induce a much higher air exchange rate
in a home, bringing in more cold,
unheated air than airtight wood heaters.[/b]

On another note - what do other wood burners do, if anything, with their furnace draft hoods (that's a chimney in layman's terms) if you don't use your furnace? I hadn't really thought about this before - should I disable the furance (an obvious important step) then stuff some insulation in that thing and seal it up? Or does it not really matter? I think that vent is shared by the natural gas hot water heater. No idea if cold air would downdraft from that thing? Even if it is shared with the hot water heater I could seal off the part connected to the furnace.

Tradergordo,

Just saw your latest post after I sent you my last one. Now I see what you're asking. High efficiency furnaces draw their combustion air from the outside and also vent exhaust gases to the outside, thus not pulling a vacuum on the house and therefore no outside airflow is induced into the house. However, older furnaces suck combustion air out of your basement, burn it with natural gas and vent the exhaust gas through your chimney to the outside. When it does this, the house pressure drops and pulls in outside air from every crack in the house to compensate for the air the burner removed from your home. When not in use, the same can happen. A strong outside breeze blowing across your chimney top can also drop the local pressure, thus pulling air past your furnace burner and up through the chimney to the outside. To compensate for lost air, the house pressure drops and pulls in fresh air from the outside through leaks everywhere in your house. Same can happen to your hot water heater. So, what to do about this when not using the furnace? Don't know...I'd consult a pro, otherwise you risk plugging something, then having an accident if you later fire-up the furnace and don't clear the obstructed pipe.

 

[elkimmeg]

Aluminized duct tape and the 2 hrs work it takes to tape duct joints will save most people a boat load of cash. Anyone can do it. I taped mine in my crawlspace and the ducts are insulated and the side-pipes carrying heat to the rooms above also have insulation.

Like alot of impormation on the internet ther is equally miss information Alumium duct tape is not considered a permant solution I begins loosing its adheisive properties ouce temps approach 120 degrees and ther for looses its seal in humid climates the adhiesive in HVAC systems is not water repelent and condensation also will cause it to loose its adhiesive properties
Studies made by ENergy Star homes al support these findings The recomendation is overwhelming in support of Duct Mastic There is a reinforced fiberglass duct tape good to 200 degree adheisive that can be uses.

Castiron I applaud you intent and effort but you unfortunately used the wrong product. again aplaus for that effeciency furnace
As far as basement living space as being with in the insulation envelope this is particially true but only if the walls foundation walls are insulater according the the zone you live in.

Then there are some situations where people just cut in heat registers to have heat acccess in the basement for the most part this has just unbalanced the system and also true supply without retuer is useless

Attic location second exchangers/ furnaces outside the insulation envelope do approach 35% heat loss in transmission and burner gasket leakage.

Castiron brings up a good point supported by energy star homes.. The best HVAC system is designed and installed within the living space. worst is exposed crawlspaces.

Insulation does not solve duct leakage duct sealant on every joint flange and elbow has proven effective.

As for sizing a stove If I may I will use another industry example when sizing a burner/ boiler to heat your home it can be oversized up to 125% and no more
the reason is the demand and effeciency curb It has to cycle x amount of time to gain and reach operating temps and supply the demand effeciently Over sizing a boiler creates a situation called short cycling simple explnation It gives out short strong blast an all at once and then takes longer to cycle back on this over shoots the apex of the effeciency curb and defeats effeciency Too many homes are also way overloaded in cooling tonage

One has to get a stove to reach and mantaine a certaint temp oversizing it it never reaches that temp undersizing you have to work it beyond its capabilities Everboud has different layouts climates needs budgets. Stove are area or zonal heaters any other heat that makes to other sections of the home is a nice bonus subtract 25 to 30% of manufactures clames it the same as oversizing you boiler 125% Going beyond that point is quite arguementive here

Slow down guys way too much hair riasing on the backs of posters recently. The subject matter gets lost in a sea of nonsense. I'm one of your worst offenders an I admit it.

 

[tradergordo]

So, what to do about this when not using the furnace? Don't know...I'd consult a pro, otherwise you risk plugging something, then having an accident if you later fire-up the furnace and don't clear the obstructed pipe.

That's why I mentioned disabling the furnace as an important step if I were to plug that exhaust pipe. I would just take the access panel off, which triggers a switch disabling the furnace so that it cannot be turned on - then plug it, and put a sign on the access panel door saying "unplug the exhaust hood if you are replacing this door!"

Still not sure if this would really buy me much. What is the diameter of your PVC exhaust pipe? I can't remember if my metal furnace exhaust is 4 or 6 inch?

p.s. It almost seems a shame that your top of the line furnace might not be used anymore! I wish my builder (7 years ago) would have given me more options, but there was no choice - they probably just picked the cheapest thing they could find rated to heat the house. Do you happen to have some amazing efficient air conditioner by any chance? Because that will probably be my next project (for next summer). My electric is REALLY expensive (>15 cents per kWh - 57% above the 2006 national average, despite living right near a coal power plant in the most coal rich state in the country, and almost within sight of a huge nuclear power plant).

 

[elkimmeg]

Trader Honestly I did not follow all your questions in the ppost but when I get back from bowling I will try to read what you ask

 

[jjbaer]

Tradergordo,

I don't have a super efficient air conditioner simply because when I did the trade-off 7 yrs ago of getting a much higher SEER (Seasonal Energy Efficiency Rating) unit, it wasn't worth it. SEER standards in effect in 1997 mandated a minimum SEER of 10 and that's what I bought and still have now. Here in the Dayton, OH area, summers aren't that hot. My worst electric bill in the hottest month is under $100 and that's the total bill for A/C and blower motor, and electric devices such as a stove, microwave, dryer, washer, garbage disposer, sump pump, fan on my water heater (water heater vents via PVC to outside but uses room air for combustion so I get some induced draft here...there's a small blower on top of the tank that exhausts the burned hydrocarbons), two garage doors, lights, power tools, etc. Newer 2006 regulations that just went into effect mandate I think a minimum SEER of 13.

As for my furnace not being made anymore, only the EXACT model number isn't made anymore.....but, Carrier still sells furnaces just as efficient (or more so) as compared to the Carrier unit I have....in fact, I think Federal law says they have to be a minimum of 78% or higher efficiency and Carriers models range from 80-96%, with some models also having the higher efficiency blower motor. And you guessed it, builders typically foist the 80% efficient furnaces with regular blower motors (insert energy HOG motor) onto the unsuspecting home owner. Then you pay through the nose for it.

You asked about the exhaust/air intake pipe on the furnace: it's two concentric PVC type pipes....air intake is one of the concentric pipes and the exhaust is the other concentric pipe hence no induced draft that can suck air out of the house and bring in cold air because it's a closed system. I think the outer diameter is about 6 inches or something like that.

As far as electricity cost, all you can do is do an energy audit of things in your house and cut back or replace with less energy consuming devices where applicable. Here in Ohio, our costs are about 10 cents/KW-HR. My last bill was 427 KW-hrs for $45 (this is not level billing but actual usage and bill). One place to start is to replace standard light bulbs with compact flourescent ones. I did this and reduced my bill by 5%....sounds small but it all adds up!

regards

 

[jjbaer]

Aluminized duct tape and the 2 hrs work it takes to tape duct joints will save most people a boat load of cash. Anyone can do it. I taped mine in my crawlspace and the ducts are insulated and the side-pipes carrying heat to the rooms above also have insulation.

Like al of impormation on the internet ther is equally miss information Alumium duct tape is not considered a permant solution I begins loosing its adhesive properties ouce temps approach 120 degrees and ther for looses its seal in humid climates the adhesive in HVAC systems is not water repelent and condensation also will cause it to loose its adhiesive properties
Studies made by ENergy Star homes al support these findings The recomendation is overwhelming in support of Duct Mastic There is a reinforced fiberglass duct tape good to 200 degree adheisive that can be uses.

Castiron I applaud you intent and effort but you unfortunately used the wrong product. again aplaus for that effeciency furnace
As far as basement living space as being with in the insulation envelope this is particially true but only if the walls foundation walls are insulater according the the zone you live in.

Then there are some situations where people just cut in heat registers to have heat acccess in the basement for the most part this has just unbalanced the system and also true supply without retuer is useless

Attic location second exchangers/ furnaces outside the insulation envelope do approach 35% heat loss in transmission and burner gasket leakage.

Castiron brings up a good point supported by energy star homes.. The best HVAC system is designed and installed within the living space. worst is exposed crawlspaces.

Insulation does not solve duct leakage duct sealant on every joint flange and elbow has proven effective.

As for sizing a stove If I may I will use another industry example when sizing a burner/ boiler to heat your home it can be oversized up to 125% and no more
the reason is the demand and effeciency curb It has to cycle x amount of time to gain and reach operating temps and supply the demand effeciently Over sizing a boiler creates a situation called short cycling simple explnation It gives out short strong blast an all at once and then takes longer to cycle back on this over shoots the apex of the effeciency curb and defeats effeciency Too many homes are also way overloaded in cooling tonage

One has to get a stove to reach and mantaine a certaint temp oversizing it it never reaches that temp undersizing you have to work it beyond its capabilities Everboud has different layouts climates needs budgets. Stove are area or zonal heaters any other heat that makes to other sections of the home is a nice bonus subtract 25 to 30% of manufactures clames it the same as oversizing you boiler 125% Going beyond that point is quite arguementive here

Slow down guys way too much hair riasing on the backs of posters recently. The subject matter gets lost in a sea of nonsense. I'm one of your worst offenders an I admit it.

Comments:

1) I'll check the type of tape I used...may have misspoken but recall using the type specifically for ductwork. Will check. Thanks!
2) I agree about duct leakage in basement...walls should be insulated...many with finished basements meet this requirment.
3) Also agree on it being a terrible idea to put A/C in attic or furnace in a crawlspace.
4) As for "short cycling", it's not "short" but the same thing happens on hot water heaters. About 50% of the energy is used to maintain the water temp....that's why demand heaters with instant hot water which have been used in Europe for over 30 years are now showing up in the USA.

 

[ourhouse]

We over sized, our house is 1400' our Quad 4300 is rated at 1800-2200 square feet. it is doing a great job at heating it.