Looking to add pellet stove to home

[Ksuwildcat2010]

Here's my situation, last year I added a Harman pf100 pellet furnace to my home I just moved into. I did this because it is a very large house, 4,000 sq ft plus some unfinished basement, and has two 35 year old propane furnaces. The original part of the house is about 100 years old. The harman is running through my old ductwork that heats only the main floor of my house, which is probably almost 3,000 sq ft. Problem is it didn't keep up very well, even with Kansas' very mild last winter, and the far end of my house and the upstairs gets quit cold, did not run my upstairs furnace.

I was wondering if adding a pellet stove, or would probably prefer a multi-fuel stove (if there is any quality ones) to the far end of my house right next to the only stairs leading up would heat that area of my house? Do you actually get much heat upstairs? Do stoves provide very even heat? I would also consider just replacing my upstairs furnace to a more efficient unit but it's in an unconditioned attic and that makes it much more difficult.

Thanks for the help and sorry for all the questions.

 

[Ksuwildcat2010]

One more question, would it be best to place the stove nearer to the center of the house, which gets more heat from the furnace, or near the end of the house that is colder and closer to the staircase?

 

[sinnian]

While I am not a big fan of the pf100 it should have been able to keep up easily. What kind of pellets did you use?

 

[Ksuwildcat2010]

I have used several different kinds, can't remember all of them. I've recently been using Ozark Hardwood Pellets. Always burn premium or super premium pellets. The furnace will be on max setting and just doesn't keep up. I can't remember exactly how many tons I burnt last year, between 8-10. Just curious why don't you like the pf100? I think i need to upgrade my blower motor, which i plan on doing shortly, but my house is just not very efficient and my duct-work isn't spectacular no cold air return. I've also never checked my draft, don't know how much of a difference that would make. Also would outside air be much help, it is sitting in a very big basement that has plenty of air flow.

I know my setup isn't ideal, but i still don't see this small efficiency improvements being able to keep up with a normal winter when last winter was very mild.

 

[jtakeman]

How much pink stuff is in the house?

Also you would be surprised how much heat loss is in the ducts and no air return. I'm betting on a cold day you loosing 20 to 25% of the heat. Sealing the seems and insulating the duct is not all that costly. Nor is adding the air return. A lot less than the price of the stove. Even if you added another stove, Your main heat source isn't efficient and you just throwing cash out the window.

IMHO I'd fix up the ducting and see what happens. If you still struggle to stay cozy? Then add the stove.

 

[SmokeyTheBear]

How many and what kind of windows are in that tiny shack you are trying to heat?

Air infiltration can also be a big waster of heat.

 

[Defiant]

4000 sq ft, some over 100 yrs old Post up some photo's, we love pics

 

[Ksuwildcat2010]

No idea how the insulation is, I know i'm losing a lot of heat in my duct-work that isn't insulated and is running through an unconditioned crawl space. Also the floor of of the original house has no insulation under it, which is where the ducting is running. I was planning on insulating the duct-work this summer but it is in a very tight area and I'm not sure how to go about it, it even has some trunk going through it.

As far as windows, 60, with many of them being large and about half are probably 100 years old, they do have storm windows if that helps much.

My next question, is since I doubt I'm going to get my ducts insulated yet this year, would a bigger blower help with the heat loss. It would seem to me that if you increase the velocity of the airflow, there would be less of a temperature difference and you would lose less heat, but I'm not engineer. Just for reference I'm currently running only a 1000 cfm blower that is quit under-powered for my duct-work, but I can feel heat through all of them, just no real air flow through some.

 

[Ksuwildcat2010]

I'll try and take some pics sometime soon. That's why I'm not real disappointed in the pf100, i knew i would be working it hard, it did a pretty good job overall. Used nothing but wood pellets to heat it all of last year.

 

[Ksuwildcat2010]

Also what real benefit does the air return do, other than help circulate the air flow?

 

[Ksuwildcat2010]

O, and probably 1,000 sq ft of it has probably 20 ft or so cathedral ceiling.

 

[jtakeman]

What insulating the duct and adding the air return do is take(isolate) the basement out of your loop. Right now your heating the basement. It may not be as warm as upstairs, But your warming it up a great deal. The air return isolates the basement from the heated air that has to return to the furnace. The air that goes back to the furnace thru the air return doesn't heat the basemant except for the little heat loss you get. Your basement will be much cooler and its will keep the heat upstairs. This will also save you money as you will not use as much fuel as well.

 

[IHATEPROPANE]

Your duct sounds like mine...I spent a lot of money on propane just heating the duct work in my crawlspace and attic...my house is smaller and my furnace could barely keep up so I am not surprised with your inability to heat tour house well with your pellet furnace.....
I think you best bet would be insulating and adding the return.....or maybe no pellet furnace but two free standing units???

 

[Ksuwildcat2010]

So doing nothing but adding a return I will actually see improvements? I can pull that off without too much trouble, if you can't tell I'm doing all the work myself. I don't know what to do about the ducts, I've thought about tearing it all out and replacing it with flex duct, but with the trunk running down there too i don't know what to do.

 

[DexterDay]

Yeah, the Cold air return will eliminate the basement heating. The furnace itself will provide some radiant heat and keep it warmer and moisture levels down. While keeping the upstairs warmer.

 

[jtakeman]

So doing nothing but adding a return I will actually see improvements? I can pull that off without too much trouble, if you can't tell I'm doing all the work myself. I don't know what to do about the ducts, I've thought about tearing it all out and replacing it with flex duct, but with the trunk running down there too i don't know what to do.

Yes, Not using the basement as the air return will show major gains. But to see the full benefit you need to do the whole package. You'll still heat the basement with duct loss(heat that radiates off the ducts). And don't worry, The furnace itself will probably radiate enough heat to keep the basement from freezing.

 

[Trickyrick]

Guys. We need to look at this like any other heating system. The op had 2seprate furnaces because one would not keep up. We know it is forced hot air but no return and there is no insulation where ducts are moving through unseated space....

Before the op invests in another heating system they need to clean up the low hanging fruit.

1) fix your source duct. You need to get the hot air to the living space. Tape seal and insulate all of your ductwork. Where the ducts are in unseated space get them insulated....

2) return air get it piped back to the furnace. If you do no you are just wasting energy heating outside air to inside temps. The flip side is that you are pushing warm from the inside air out through every crack.

3) insulate your house. Keep the heat in the house and you will be amazed how much warmer you are.....

4) if all else fails investigate a stove for supplemental heat. But this should be your last resort as it will cost you more than all the others combined and will also cost you more fuel. Better to insulate your house and save more each year then have to buy more pellets......

 

[TheMightyMoe]

112k BTU pellet furnace sounds like you are cutting it TIGHT even for a well insulated 4k square foot home. (I live in a 1.8k 4.5 Star requires 54k BTU per energy audit).

HOWEVER

I AGREE 100% WITH THE ABOVE. Focus on tightening up the house! Install return air where possible! Insulate! (Get that attic to R50, it is very easy, and a do it yourself job) And you will probably be fine.

 

[Ksuwildcat2010]

TrickyRick, I believe the house originally had 2 furnaces and ac's more for the ability to have separate temperatures upstairs and downstairs. The propane furnace downstairs that is i believe 125,000 btu and is 35 years old heats the house very well, but costs an amazing amount. That's what i don't really understand, based on the efficiency of that furnace i should be putting out more btu's but I'm not getting near the heat, the only difference in ducting is that the propane furnace has the air return hooked up, which I guess I will try next.

 

[SmokeyTheBear]

You need to do something about the amount of glass and air infiltration as well. Look up interior storms and build some. You can also bank your house if you can find the materials. That will somewhat insulate the foundation and crawl spaces.

As has been mentioned, all joints in your duct work need sealing, you are losing air flow if they are not air tight. You might benefit from a higher cfm blower, but even then you really need sealed duct joints and that duct work should be insulated when it passes through non-heated areas.

Do a quick volume calculation on the inside of your house both including your basement since you haven't got the return air hooked up and without the basement. Take both figures and divide them by the cfm rating of your PF100's convection fan, that will tell you how long in minutes it takes it to move the air in your house assuming there is no air infiltration. Everyone gets hung up on the square footage, when it is the volume of air that needs to be heated that counts.

Visit hearth.com member garygary's site http://www.builditsolar.com/ and take the heating calculator out for a test drive.

 

[Trickyrick]

TrickyRick, I believe the house originally had 2 furnaces and ac's more for the ability to have separate temperatures upstairs and downstairs. The propane furnace downstairs that is i believe 125,000 btu and is 35 years old heats the house very well, but costs an amazing amount. That's what i don't really understand, based on the efficiency of that furnace i should be putting out more btu's but I'm not getting near the heat, the only difference in ducting is that the propane furnace has the air return hooked up, which I guess I will try next.

I would bet a ton of pellets the reason ofr two furnaces was that they couldn't keep up with one. If they wanted to zone it and already had the piping(ductwork) there that would have been much less expensive. Nahhh they needed more BTUs. Either way you didnt run propane last year upstairs and heat rises. The upstairs of your home robbed from the 3000 SQ feet you were expecting to heat.

The PF100 is rated to burn 112,000 BTU per hour at 89% efficient So the absolute best you get out is 100,000 BTUs then add in heat exchanger efficienies which drop depending on how clean the exchanger is kept. On the best day you are looking at a 20% drop in heating capacity vs what you pulled out.

To make up for that you will need to do the insulation thing. I think you can get there but you need the return air, insulated ductwork and insulate the home. All of these together will stil be cheaper in capital and long term costs than adding another local stove.

If you have a monthly bill (gallons used) from Jan on any year (tell me the year) when you heated with only propane I can tell you how many BTUs you used that month and we can compare it to what you have now and we can see what is going on.

 

[Ksuwildcat2010]

Well the second furnace was added when the house was added on, but I'm sure that 112,000 btu isn't enough to heat the whole house appropriately No sure on what gallons have been used, but it was a lot. Well I guess I'll try and figure out some better insulation, thanks for the help everyone.

 

[DexterDay]

What CFM size is on the Gas Furnace?

My Pellet furnace is an 800 CFM unit. It heats my home just fine. But compared to the LP furnace (just over 2,000 CFM) its a drop in the bucket. I am heating close to 3,000 sq (2,200 up amd about 800 basement/ no cold air return hooked up) but I have fully insulated ducts and a woodstove cranking about 15 ft away. So the furnace sucks the 90° air out of the basement from the woodstove and distributes it throughout the house, via the HVAC from the Pellet furnace. Works pretty good. Without the woodstove going, it has to work quite a bit harder, as my pellet Furnace is only rated at 50,000 BTU.


Insulating (ducts, house, attic, and windows) will help tremendously. As will a Cold air return (of proper size to keep static pressures in check) and possibly a bigger distribution blower for the Harman (they make a 2,000 CFM) if your longer runs are not getting the flow needed?

 

[jtakeman]

To make up for that you will need to do the insulation thing. I think you can get there but you need the return air, insulated ductwork and insulate the home. All of these together will stil be cheaper in capital and long term costs than adding another local stove.

Not to mention it will save you money in fuel every month as well. So there is a return on the investment. Just adding the stove will probably not have a return at all. My 2 cents.

 

[Ksuwildcat2010]

I can't find the cfm on the gas stove, just shows it being 3/4 horse. The farther end of the house is where I'm not getting much flow. And to be clear my attic is insulated, it has some blown in on the floor, I'm sure not nearly enough, I was just saying that the rest of my attic isn't insulated so you can't really put a high efficiency propane furnace up there.