Combining Hard Fired Stove & Forced Hot Air Heat

A friend of mine has a small house, less than 1000 sq feet with a basement and 2 additional levels of living space. All heated by an oil burning forced hot air. The house is an old construction and originally heated by a stove in the basement that exhausted up a central chimney stack. The stove was removed before my friend purchased the house and and forced air furnace installed. Regardless, its an old furnace and very inefficient and a season's oil bill is over $1500 for such a small area. This doesn't include DHW which is provided by a propane tankless heater.

1. Friend would like to reduce oil costs. A new furnace is out of the question at the moment. Furnace is exhausted into the same stack that the previous stove used. We are wondering if the furnace can be powervented out to the side of the house. Can powerventing be added to any type of furnace or are we stuck with exhausting into the chimney stack.

2. Adding a stove. Assuming the furnace can be powervented, this would free up the chimney for a stove. There is a concrete pad next to the chimney in the basement where an old stove once stood.

3. Reason we think a stove would work to reduce oil consumption is for two reasons. Having a stove running in the basement would over time heat the floors above it. Warm air from the basement would slowly rise up and warm the living areas above. However, the main reason is because the forced air furnace's cold air return is located in the basement next to the stove (there is actually a return duct that has several openings in the basement. this duct also rises up and returns air to the furnace from the first floor as well) We think that if the air being fed to the furnace return was already warmed by a stove in the basement, than that stove's heat could be more easily distributed around the house by the forced air system. That system should burn less oil to warm the air if the air entering it is already warmed by a constantly running stove.

Anybody see anything wrong with this idea?

NJJoe wrote:1. Friend would like to reduce oil costs. A new furnace is out of the question at the moment. Furnace is exhausted into the same stack that the previous stove used. We are wondering if the furnace can be powervented out to the side of the house. Can powerventing be added to any type of furnace or are we stuck with exhausting into the chimney stack.

My starte home had an oil fired furnace with a powervent poked out the wall. Just make sure you have some type of relay set up that the oil furnace wont fire unless the power vent is running or bad things could happen. Nothing like a mac truck exhausting in your basement.

With an area that small, I say chuck the oil furnace and replace it with a used forced air coal furnace.

I recently did that. No regrets I found my furnace on Craig's List for $650. He would only burn 3 tons max. A used furnace would pay for itself the first year.

For resale keep the oil furnace, and keep an eye on craigslist for a higher efficiency one for sale..
You can't sell a house or even refinance a house without a 'conventional fuel' heat system.. Mortgage companies have no imagination.

Adding a stove is a fine idea, but try to find one that has a fan then get creative with making a hot air duct for the stove, and make a
cold air return for the distribution fan on the stove, this makes it into a mini-furnace. Just heating the basement is not a good way to
heat the house above, the cold basement walls absorb a lot of the heat.
Read in the plumbing, chimneys, ducting forum about distributing heat, there are MANY threads on the subject.

Powerventing a oil burning device is a good idea, the powervent only runs when the oil burner runs, so it doesn't cost much
or wear out fast.

Let us know what stove you have in mind, we'll share our knowledge on the stove.

Greg L

Lightning wrote:With an area that small, I say chuck the oil furnace and replace it with a used forced air coal furnace.

I recently did that. No regrets I found my furnace on Craig's List for $650. He would only burn 3 tons max. A used furnace would pay for itself the first year.

The first cheapest by far improvement would be to connect the cold air return to the living space. You can not pump air in without pulling air out and leaving a door open to the cellar is another poor idea as you have added that to the heated space. A sloppy install of an oil furnace is not the fault of the oil furnace just the ignorance of the installer stealing money from the home owner for the life of the system. There is 25 to 50% savings there.
Dave

Two people that I work with pull cold air off the basement floor, heat it and then pump it into the house with no way for it to get back to the furnace. It's so frustrating that I can't seem to convey how grossly inefficient this type of arrangement is. Some people just can't be reached lol. They have no concept that air is matter and has mass and volume like anything else.

This is an old stove that I connected to the cold air return on my furnace. It blows hot air in the living space upstairs using the cold returns and god forbid if the furnace is used the air going to the furnace is preheated to approx 200* furnace does not stay on long, I think I used 20 gallons of fuel the winter and 2 and a half ton of coal! My basement is nice and warm as well. Your situation brings up a point of putting the stove on the first as well as the basement. I paid 4 hundred bucks for my stove 2 yrs. ago, there are deals out there!

Lightning wrote:......... They have no concept that air is matter and has mass and volume like anything else.

......excellent point and once I understood that principle, heating my home became much easier!

Lightning wrote:Two people that I work with pull cold air off the basement floor, heat it and then pump it into the house with no way for it to get back to the furnace. It's so frustrating that I can't seem to convey how grossly inefficient this type of arrangement is. Some people just can't be reached lol. They have no concept that air is matter and has mass and volume like anything else.

The bottom line is the blower is an air circulator not a pump that can pressurize the house by a great deal. If there is no return air in the heated space there is no circulation and little heat is delivered. If you let the return air go back to the basement with a basement door open you are chilling the heated return air back down to basement temperatures and adding the volume of the basement to the heated area including all it's heat losses as well. The R value of concrete or stone is very low. There are dozens of reasons it is a bad idea. A few well placed returns would do wonders for their heating bill.

Also if you put a stove in the basement with the blower running and do not have enough make up air what is stopping the negative pressure from the blower from pulling flue gases out of the stove and into the house? The answer is nothing.
Dave