What's the best type of furnace?

[Dawg]

I once had a heating/cooling tech tell me an oil furnace is the best furnace as of keeping you warm but the only downfall is they spread a dirty film on everything.

I can relate to this as I grew up in a home with an oil furnace.

But then I see there are gas furnaces, and have wondered in comparison to an oil furnace how efficient are they.

I lived in a residence once with an electric furnace....I didn't think it did a good enough job keeping the place warm....didn't help much it was a mobile home.

My current residence (one story house) has a heat pump. Not too sure I'm real fond of it.

Anyways just wanted to get your input on what's the most efficient, what's not, etc.

BTW I reside in NC but I grew up in IN.

[LazyPup]

We often hear the age old arguments about which furnace is better, but in the end they all perform one basic function, they transform either electrical or fossil fuel energy into heat energy.

The key to success is you have to begin by doing a thorough heat loss study on the structure to determine how many BTU's you actually require in the worst case scenario, then design the entire heating system accordingly.

The furnace symply produces the heat. Once the heat is produced you are confonted with the problem of distribution. The most efficient furnace in the world would soon prove inadequate if it cannot distrubute the heat evenly throughout the structure.

Often homeowners make the mistake of installing a new high effeciency furnace while still retaining the old 1940's ductwork or piping. The end result is inefficiency.

When a duct system is first installed, the installers take great care to properly size the ducting to meet the demands of each room or zone within the structure. They then go throughout the system and adust dampers and registers to insure a balanced airflow.

Enter the homeowner and they immediately begin fiddling with the dampers and registers in the vain hope they might save a dollar or two by closing off the seldom used room. Little do they understand that closing off one room will instantly upset the balance to the next one.

So to get back to your original question, which is the best furnace. The best furnace is the one that will produce the amount of BTU energy to supply the needs of your home, providing it is connected to a properly installed and balanced distribution system.

The determination as to which is the best fuel source depends upon the average availability and pricing of the fuels in your region.

Technically speaking electric heat is the most effecient because there are no associated flue losses, therefore electric delivers 100% of the energy it consumes. But if we were to break it down to cents per BTU, given the fundamentally high cost of electrical energy electric usually is way down the list in economics.

Although many people will argue the point,non the less, the facts prove that a woodburning fireplace is absolutely the least effecient source of heat, due to the extreme amount of combustion air and flue losses.

If one were to attempt to decide which fuel based upon operating cost you would have to begin by determining the BTU requirement for the structure. You then have to determine the actual percenatage of delivered heat for each furnace based upon its percentage of efficiency, Then compute the gal/hr cost of the fuel for that furnace based upon the average cost of fuel in your region. By example, in the northeast fuel oil is very common and the prices are fairly reasonable, while here in western Pa and Ohio fuel oil is almost non-existant. In fact some communities in this region do not even permit installing an oil burner.

Given that this part of the country is one of the richest GAS reserves in the world one would think gas is economical here, but in fact natural gas prices here are amongst the highest in the entire USA, all the while 80% of all gas producing wells in this region are capped. Go figure.

[imeduc]

The best and only way to go today Go to http://www.warmair.net and compare fuel cost there where you are. All we sell in Cen.Missouri is heat pumps right now

ED

My mistakes dont define me they inform me.

[Kidd6488]

No one made any mention to geothermal... Aside from the upfront costs, we are waiting to see the comparison to our old in-ceiling cable heat...

~Jonathon Reinhart

[Kidd6488]

No one made any mention to geothermal... Aside from the upfront costs, we are waiting to see the comparison to our old in-ceiling cable heat...

~Jonathon Reinhart

[Dawg]

quote:Originally posted by LazyPup

The key to success is you have to begin by doing a thorough heat loss study on the structure to determine how many BTU's you actually require in the worst case scenario, then design the entire heating system accordingly.

Often homeowners make the mistake of installing a new high effeciency furnace while still retaining the old 1940's ductwork or piping. The end result is inefficiency.

When a duct system is first installed, the installers take great care to properly size the ducting to meet the demands of each room or zone within the structure. They then go throughout the system and adust dampers and registers to insure a balanced airflow.

Enter the homeowner and they immediately begin fiddling with the dampers and registers in the vain hope they might save a dollar or two by closing off the seldom used room. Little do they understand that closing off one room will instantly upset the balance to the next one.

So how would you determine what BTU your home needs?

What is wrong with having 1940's duct work with a modern day furnace?

So if I have one room I never use and I keep the duct closed that's actually hurting my heating capabilities?

[LazyPup]

Back in the 30's, 40's and even up into the early 60's fuel was comparitively cheap and there were no EPA regulations. (EPA began in 1971). In those days coal was the primary fuel, followed by wood and in some regions oil. Natural Gas and LP were in their infancy as a heating fuel, and often they simply used a coal furnace with a conversion burner stuck through the cinder door on the bottom of the combustion chamber.

Most furnaces of that era were gravity convection type, although they were in the stages of bringing in blowers and forced air. Heating ducts were huge, with 20" to 24" primary being common. Often on multi-story homes the heat was only put into the ground floor and they installed registers through the floor from the ground floor to the upper floor, which allowed the heat to go up from natural thermal convection (as the heat rose to the ceiling it then went through the register to the upper floor.)

The alternative was steam radiation, which was piped throughout the houe.

Hydronics (circulating hot water) we also in their infancy at that time.

Although there was some effort to install return air, for the most part return air was unimportant as most of the heated air went right out through the roof and walls, and the basements were so drafty there was a constant source of both combustion and makeup air.

Here in North east Ohio our winter temps average near zero and we commonly get snow on Thanksgiving which is often still on the ground on Easter Sunday, coal was $9 a ton delivered to your home, and we could heat the entire winter with 6 to 8 ton so there was really no demand for high efficiency in either house construction or heating systems. The down side was that you had to manually stoke the fire every 2 hours, bank it down with fresh coal and ashes at nite, and wake up to a cold house in the morning, not to mention, you had to constantly carry the ashes out. But then, we dumped the ashes on the driveway so we could get through the ice and snow so it all seemed to work out.

The idea of really designing effecient heating systems didnt come into play until Air Conditioning became poplular in the mid 60's. Air conditioning demanded electricity, which was a fairly expensive utility, so along with air conditioning came improvements in house construction as well as carefully designed air flow HVAC systems.

Once the EPA was enacted in 1971 we were no longer permitted to install the old smokey joe coal furnaces or dump the ashes on the driveway. The trend was then to find a more convenient and clean burning fuel. In those days natural gas was a byproduct of the petroleum industry which was used for cooking, water heaters, or industrially, but the majority of it was burned off in atmospheric flare stacks at the refineries. Now they had a viable market for it. Within a very short time that market was so good that they actually were drilling GAS wells as well as oil wells.

In the old days of coal furnaces, if you were cold you opened a register, and when you got hot you closed it. Along came designed forced air flow systems with ducted return and people simply did not understand the technicality of air balance. They continued to open and close registers at will, not realizing that if you close a register you cause a backpressure on the trunk line, which in turn upsets the balance to the entire system.

Modern furnaces have high limit switches and in some cases air flow sensors. shutting off too many registers will cause a back pressure on the plenum, causing it to overheat and shut the burner off. The end result is short cycling the burner.

As far as closing off unused rooms. That is fine, if you have a heating system that is designed for zone operation, but if it is set up for whole house operation shutting a room off will cause an imbalance that may even result in higher fuel costs.

Properly, when a modern HVAC system is installed, the first step is to do a complete Heat loss study of the structure to determine the required BTU demand for your house.

When conducting a heat loss study, you have to examine every room in the house, one at a time. First you determine the total linear footage of outside wall, then examine the construction of that wall. You then have to factor in for doors, windows and other openings, as well as consider what is under the floor? Is it another heated space? A slab? an unfinished basement? etc etc. They you factor in what is above that room, another heated space? an attic? flat roof? etc etc. Then you move on to the next room until you have the entire house.

You then have to factor in Infiltration, which is the amount of air that can permeate the exterior walls and celings.

Once that is done, you have to factor in wind and solar load, which is effected by geographical conditions. Trees, hills, elevation above or below average terrain, proximity to other buidings etc.

We often hear people give a square footage for thier home and want to know the BTU requirement. While there are some rough rule of thumb formulas that are used, in truth, that method is little more than a semi-educated guess. In fact, if a contractor were to build ten homes on the same floor plan, using the same materials and workmanship, due to geographics, solar and wind load variations, all ten would still work out to a different BTU requirement.

Once the total BTU demand is figured out, they then consider the actual volume in cubic feet of each room and design the duct to supply precisely the correct volume of air to that space. Properly the ducting system should be designed to give 3 to 4 air exchanges per hour. Therefore, if you have a room 10 x 10 x 10 it has 1000 cubic feet of volume. To get 3 exchanges per hour you design for 3000 cu.ft/hr which when divided by 60 minutes per hour, the duct is sized to allow 3000/60= 50cu.ft/min. Closing that regester off now dumps an additional 3000 cu/ft/hr into the other rooms, which then literally blows the air back to the return before it has time to adequately heat the space.

[Dawg]

Wow.....lots of good reading.

My mother grew up on a farm in rural southern Indiana. She told of how at night the fireplace kept you nice and cozy but in the morning you woke up to a cold house and could see your breath.

The house I grew up in was built in 1948. I think it was built with electricity and an oil furnace but I am not 100% sure. My parents said it had an oil furnace when they moved there in 1977. They converted to gas in 1998.

I recall a friend of mine whom used to live a few miles from me in an old farm house. I recall one room downstairs had what looked like a round disc in the wall which I believe was once where a furnace or stove once sat.

I also recall one of the bedrooms upstairs had a vent in the floor....you could look thru it and see the downstairs below. I imagine this is what you were getting at by saying "Often on multi-story homes the heat was only put into the ground floor and they installed registers through the floor from the ground floor to the upper floor, which allowed the heat to go up from natural thermal convection (as the heat rose to the ceiling it then went through the register to the upper floor.)"


What's more....across the hall was my friends brothers room. It had also a disc on the wall where it looks like a furnace once was. This is on the same side of the house as the downstairs disc sat. So I imagine it was one big chimney where 2 furnaces connected to?

Oh....the house I live in now has a heat pump. Which is why I was inquiring about if I needed all registers open or not.

[LazyPup]

The house I grew up in had a huge coal furnace in the basement, about 6 feet in diameter and 7 feet high. Those old furnaces had a big lever that you pushed and pulled to shake the grates to get the ashes to fall into a pit under the firebox, then you had to shovel those hot ashes out onto the floor and let them cool before you hauled em outside. About every two hours you had to shake it down, then add a couple shovels of coal to the firebox.

At nite just before going to bed you would add about three to four big shovels of coal, then get a couple shovels of ashes from the pit and sprinkle then on top of the coal to retard the burning rate. That was called banking the fire.

First thing in the morning you had to take a long poker rod and stir the fire to break up a big clinker that formed from the ashes and burning coal, then add a couple shovels of coal to get the heat going again.

In the kitchen we had a huge white enamel finished stove with a cast iron top about 4 feet wide and 2 feet front to back. There were round cast iron lids about the size and spacing of modern burner elements. You took down a steel handle and lifted those lids, stirred the coals and added some more coal to get the stove going. You opened a little door on the side and there was a crank to shake the grates to shake the ashes down.

The only heat to the bedrooms on the second floor was three of those through the floor registers and as the fires burned down at nite, it was common to have frost on the inside of the bedroom windows by morning. Grandma had three large fire bricks that she kept in a little warming compartment on the lower left side of the stove. Just before bedtime we would take one of those hot bricks and wrap it in a towel, then we would take it to the bedroom where we tucked it under the covers at the foot of the bed to keep your feet warm.

There was a big old two gallon coffee pot that was perked the nite before, then left on top of the stove all nite so you had a hot coffee to wake you up..and i mean wake up..after sitting on the stove all nite that coffee was blacker than the coal, in fact. to this day i often affectionately call my coffee "Swamp water"

Everybody kept their work shoes or boots under the kitchen table so they would dry out and be fairly warm in the morning. There was many a winter morning when we would rush off to the barn to start our chores because it was warmer in the stable with all the cows than it was in the house.

We also had real running water..one of us boys had to take a five gallon bucket and run out to the spring to get it, which was about 150 yards through snow and ice.

For a real eye opener in the morning, the bathroom was a little 4 x 4 privy about 50 yards behind the house. I gurantee nobody sat on the john to read the paper in them days. We had a Sears Catalog in the privey, but it wasnt for researching your christmas wish list.

I was 14 years old when they finally installed a pump for water and built an addition so we could have indoor plumbing. Imagine that, a real bathtub with hot running water. No more galvanized pails heated on the stove and carried to a cold bedroom for a sponge bath. (maybe that is why i enjoy working on plumbing today.)

[Dawg]

Man, if only some people knew what it used to be like.

My mother also told of them having an outhouse and how in the winter it was cold to go out and have to sit on the toilet and how in the summertime flies buzzed away inside. I'll bet anyone who had to use one back then did their buisness and got it over with right away.

She also told of how they had a big round tub that you had to go out and fetch the water, then bring it in and let it sit on the stove just to have a nice warm bath.

So did the modern day furnace come about in the 60's? Did they not have them in the 40's and 50's?

[LazyPup]

I was born in 1947 so my earliest memories would be from the mid 50's on. There were some gas furnaces avalable, but for the most part all the homes i remember seeing with gas heat had open burner gas space heaters that were attached to the gas line by means of a rubber hose attached to a petcock. A pettcock is a valve with a tapered tubular output so you can slide a rubber hose onto it. The hose was only held in place by the friction of the rubber.

The space heaters were cast iron frames with open flame burners, although some had ceramic inserts that disipated the flame and produced a bit more heat. The looked very similar to the gas logs you now see for fireplace inserts. There were no pilot lights, no automatic gas shutoff valves and worst of all, no flues or vents. You turned the gas valve on and lit the burner with a match then regulated the height of the flame by opening or closing the gas valve to throttle the gas.

There were two gas lines to the furnace, the primary fuel line and a small diameter pilot line. The pilot line had a small hand operated gas valve. When the valve was open there was gas to the pilot, whether the pilot was lit or not. They then used a solenoid valve to control the main gas line so when the thermostat called for heat it electrically opened the main gas valve, and if the pilot was lit, the burner would lite off, but if it wasn't the house got filled with gas.

Most of those furnaces did have a rudimentary safety control called a BASO switch which had a thermocouple in the pilot flame to hold a manual reset switch closed. The low voltage from the thermostat went through the BASO switch to the gas valve. As long as the BASO switch was in the closed position the thermostat could energize the gas valve solenoid to control the burner. If the pilot went out the thermocouple cooled down and the BASO switch would open the circuit to the gas valve so the gas valve couldn't open until after someone re lit the pilot and manually reset the BASO relay.

Gas water heaters just had a manual shutoff valve on the gas line. Many did not even have thermostates. I can recall many houses blowing up because a furnace pilot blew out, or a water heater flame blew out while people were away, filling the house with gas, and when they returned home, they happened to turn a light switch on before noticing the gas, and just the minor spark in the light switch was enough to ignite the gas and blow the house up. I can also recall water heaters overheating and blowing up too, but then if the gas didnt blow up, you also had the risk of carbon monoxide poisoning from the open gas space heaters or because most gas water heaters weren't vented at all.

Actually, when i think about it, the modern gas appliances are really modern marvels compared to those we used a mere 30 or 40 years ago.

[Hube]

This a very interesting and nostalgic subject.
I don,t have much of anything to add except that in the late 40's and early 50's, I was installing new forced air furnaces and streamlined custom ductwork for the replacement "gravity type" furnaces. It seemed that only the 'well to do' type of people could afford them at the time.
This was in the central Ontario area of Canada.

Btw, OIL heat, if the unit is well maintained,etc, will give you clean, safe, comfortable heat. Oil burners have come a very long way over the years to overcome the dirty film theory. In fact at present in our area it is also the most economical type of fuel.

[LazyPup]

Hube...I have to agree with you in regards to Oil heat. If I had to make a personal choice between fossil fuels Oil would be my first choice. Unfortunately for reasons totally unknown to me, many counties here in Northest Ohio have banned the installation of oil heating systems, But I personally believe that is due more to local politics than any viable problems with oil. But then when one considers that this region is one of the leading producers of Natural Gas, and it is no secrete to anyone that we have more than our share of corrupt political officials, which is evidenced by our Congressman James Trafficant currently in Federal Prison for corruption, not to mention that in the last 6 months more than a dozen local policeman have been arrested for theft or drug related charges, and three of the local sheriffs and an untold number of Deputies are currently under indictment, as well as a couple county commissioners, building inspectors and other civil servants in our local for payoffs and other corrupt acts.

I would agree that in the Post World War II era, high tech furnaces and quality duct systems were available, but only affordable to commercial or the High End housing market. To put it in perspective, I would guess that streamlined ducting such as Hube mentioned was at the time probably about the same as Geothermal Heatpumps are at this time.

During that same period there was a minor rennasaince in housing construction in general. The custom home market was moving away from the old site built multi-story victorians in exchange for One-story "Ranch Homes". During the war they had developed "prefabricated structures" which were precut kits that could be quickly erected on site to meet the needs of the military. After the war the trend caught on quickly with the general public. I remember seeing in the Sears & Roebuck catalog that you could order a complete home kit. Once you purchased the kit, you recieved the plans and you prepared the foundation, whether it be on slab or a basement. Your new home arrived on site totally complete, precut framing, sheeting, doors, windows, roofing shingles, copper pipe and fittings, ducting materials, etc etc. Basically all the prospective home owner had to do was choose the floor plan, aquire the land and prepare the foundation then arrange for the labor to put your kit together.

WW II had ushered in Atomic Energy, Radar, Jet planes and even Ballistic missles of a sort with the German V1 Buzz bombs and the V2 rockets and the introduction of plastics. The general public was fixated on "UFO's and in the early 50's "Space Age Technology" was almost a household word. Once molded fiberglass products were available to the general public for a period they almost took over. Everything from cast iron bathtubs to wooden bowling alley and restaraunt furniture was now being replaced with Space Age Molded fiberglass. In fact, AMF Brunswick was converting their bowling alleys so fast that they had to build a Fiberglass production plant to meet their needs. A few years down the road when they had basically retrofitted all their bowling alleys, they still needed to keep the factory open to make repair parts so they had to look for another market for fiberglass. Someone hit on the idea of making fiberglass boats and that was the origin of Bayliner Boats, which went on to be one of the best sellers on the market today.

[mrcaptainbob]

Wow! Talk about bringing back the memories! My grandma and grandpa's place had the old ising glass pot belly in the dining room and a stove just as you describe in the kitchen. Although they did have the modern convenience of paper wrapped bricks of coal that were kept in the kitchen to feed the stove there! Oh yeah, and the tin box on the wall where you pull out a Red Diamond stick match....
Clinkers....banking....lighting the coils for the water heater (summer only)....ashes, Anyone under 30 listening to us have their eyes rolling to the heavens waiting for us to talk about going up hill both ways to school....Talk about an improved standard of living! Thanks for installing all those new heating and plumbing systems guys!!

[LazyPup]

Paper wrapped coal? wow..what luxury. All we had was "Run of Mine coal"

We would take the old truck to the open pit strip mine and get a load of coal just as it comes out of the ground. A big front end loader scooped it out of a pile and dumped it on the truck, and when we got home, guess who got to shovel it off the truck and down the home made wooden coal shoot to the coal bin in the basement? WE had to keep a sledge hammer handy to break up the large chunks, often a foot or so in diameter. For fun we often sat around the coal bucket in the kitchen with an old shoemakers hammer and cracked the coal apart searching for fossils. When we found a fossil, which was very common, we would sit it on the window sill and show it off for a few days before it mysteriously dissappeared.

I still have the old metal match box holder, and out of nostalgia it hangs in my kitchen, complete with a box of the old wooden strike anywhere matches.

I remember sitting at the kitchen table doing my homework with those old antiquated wooden word processors with the eraser on the other end too,,,heheheheheh.

I showed some of the neighbor kids my old slide rule and they couldnt believe it, Imagine that, a calculator with no batteries or solar cells.

My Grandad told me that back during the great depresion in the late 30 no one had any money to buy anything so Sear & Roebuck sent out blank catalogs so ppl would have paper for the privy..