HVAC guys please

[Fanatical Meat]

I have a forced hot air furnace that is more than 30 years old. I just had it serviced and its 83% efficient after some parts were replaced last year. I know its getting pretty old and will need to be replaced. Oil is my only option.
Newer furnaces don't seem to be that much more efficient seems like the average is around 86% any suggestions what I should look for?
House is in the North East and about 1200 sq feet. I am currently insulated very well.

 

[Jimzz]

Looks like 86% is about the best for a oil furnace. No natural gas option? I have only dealt with heat pumps and gas furnaces.
What do you have now that is 30years old and is 83%? You sure its not 73%?

But also make sure the duct work is sealed, that's a major one I see. That includes the return.

 

[NetWareHead]

I have a forced hot air furnace that is more than 30 years old. I just had it serviced and its 83% efficient after some parts were replaced last year. I know its getting pretty old and will need to be replaced. Oil is my only option.
Newer furnaces don't seem to be that much more efficient seems like the average is around 86% any suggestions what I should look for?
House is in the North East and about 1200 sq feet. I am currently insulated very well.

Are you sure that newer furnaces are not that much more efficient?

You shouldn't just look at efficiency. Newer furnaces also carry a lower cost of ownership and maintenance. Eventually, you will find that the parts that break on your 30+ year old system are not as readily available and repairs will start costing more and more. New blowers for forced air are also quieter and can use less electricity.

What is your goals when analyzing this system? Greater efficiency/capacity?

 

[Fanatical Meat]

Good points guys, it definitely scored an 83% yesterday. I was surprised because it has hovered around 80% for the last 3 years. I forgot what part they changed but its like the carburetor in a car. My goal would be more even heat (the back part of the house is not heated well) and better efficiency. I am just beginning to look at replacement.

 

[NetWareHead]

Good points guys, it definitely scored an 83% yesterday. I was surprised because it has hovered around 80% for the last 3 years. I forgot what part they changed but its like the carburetor in a car. My goal would be more even heat (the back part of the house is not heated well) and better efficiency. I am just beginning to look at replacement.

I'll offer my own experience with forced air and this is my experience only with the installations I have had the displeasure of dealing with. YMMV. I dont like forced air since it is uneven heat. I don't like the cycles of cold and hot. I don't like the fact that dust gets blown around the house. IMO, hot water delivered to baseboard radiators is a superior heating solution. Hot water holds more energy than hot air and that translates to more even feeling of heat with less temp swings and greater comfort. I like how hot water systems can easily be zoned and typical forced hot air is all or nothing. if I were trying to remedy "uneven heat", I'd get some hot water radiators in there. Whether or not you are willing to rip out your ductwork or add water pipes for hot water is up to you.

If you want more heat in a colder section of your house, you only choice is to add more ductwork so you can throw heat where it is needed. Another route you could take is to add a separate heat source in or near that area to supplement the deficiency in the existing system. You could add an electric, wood, propane, wood pellet or coal stove.

 

[fstime]

It pretty much comes down to oil heat sucks, and forced air heat is less comfortable than radiate heat.

If you don't have access to natural gas, you are not going to get 90+% efficiency with oil, only low to mid 80's.

One option would be to convert to propane which can provide 95% efficiency easily and pretty cheaply for the furnace it self An 80K btu gas furnace probably costs around ~$700. Being in the northeast would probably mean a heat-pump wont be able to keep up in the winter.

Installation costs however is another story, and propane it self is not cheap at all being that it is a by product of oil. It is however much cleaner to burn and would get you very high efficiency.

 

[NetWareHead]

It pretty much comes down to oil heat sucks, and forced air heat is less comfortable than radiate heat.

If you don't have access to natural gas, you are not going to get 90+% efficiency with oil, only low to mid 80's.

One option would be to convert to propane which can provide 95% efficiency easily and pretty cheaply for the furnace it self An 80K btu gas furnace probably costs around ~$700. Being in the northeast would probably mean a heat-pump wont be able to keep up in the winter.

Installation costs however is another story, and propane it self is not cheap at all being that it is a by product of oil. It is however much cleaner to burn and would get you very high efficiency.

Oil heat, if we remove the high cost of the fuel, actually has a better response time and heats the boiler/furnace better than gas or propane. All things being equal, from a pure performance standpoint I'd choose oil over propane.

Propane has less BTUs per gallon than oil. True it burns cleaner and you can go longer between service intervals. IMO fuel costs are higher with propane but lack of service is more detrimental to oil. Ideally, if you want to prevent a "no-heat condition" then you are best served to service your boiler once a year, no matter what it burns.

There are high efficiency condensing oil boilers/furnaces on the markets capable of >90% efficiencies (not just limited to propane or natural gas). Condensing boilers/furnaces remove so much heat energy from the exhaust stream that the gases no longer have the buoyant thermal energy to rise and exhaust out of a chimney by themselves. As far as I know, these type of equipment cannot be vented into a chimney. Instead they need to be power vented (with an exhaust fan) out the side of a building with a PVC pipe. You also will need a drain installed near the boiler/furnace to carry away the condensate that forms. High efficiency condensing equipment is great provided you can pay and have room for the venting and condensate drainage. If not, then stick to less efficient equipment.

 

[Scarpozzi]

I've got an American Standard dual-fuel system. Heritage 15 + 95% efficient, 2 phase gas furnace...so it runs the heat pump down to 40 degrees and switches to gas heat below that. We have cheaper NG, so I use it when I can justify it.

The 2 phase option gives you a lower gas consumption rate when it's only having to maintain temp and it's also paired with a multi-speed fan unit....this way you're not forcing too much colder air over the reduced heat....so the air coming out of the vents is still warm when it's in power saving mode....

There are other options, but for me to simply replace my old 2.5 ton unit with a 3 ton American Standard system like that, I paid $7.4k....that included the gas lines as my house didn't have gas prior to that system install.

 

[slag]

I'll offer my own experience with forced air and this is my experience only with the installations I have had the displeasure of dealing with. YMMV. I dont like forced air since it is uneven heat. I don't like the cycles of cold and hot. I don't like the fact that dust gets blown around the house. IMO, hot water delivered to baseboard radiators is a superior heating solution. Hot water holds more energy than hot air and that translates to more even feeling of heat with less temp swings and greater comfort. I like how hot water systems can easily be zoned and typical forced hot air is all or nothing. if I were trying to remedy "uneven heat", I'd get some hot water radiators in there. Whether or not you are willing to rip out your ductwork or add water pipes for hot water is up to you.

If you want more heat in a colder section of your house, you only choice is to add more ductwork so you can throw heat where it is needed. Another route you could take is to add a separate heat source in or near that area to supplement the deficiency in the existing system. You could add an electric, wood, propane, wood pellet or coal stove.

My parent's house had floor registers that used hot water.

Yeah, they suck 10x more than forced air. When forced air turns on, the room heats up quickly. With floor registers, you wait, and wait, and wait, and about an hour or two later, you might feel some warmth. Since its all radiant heat from a small area near the floor on a wall, it takes forever to warm up the room.

 

[fstime]

Oil heat, if we remove the high cost of the fuel, actually has a better response time and heats the boiler/furnace better than gas or propane. All things being equal, from a pure performance standpoint I'd choose oil over propane.

Propane has less BTUs per gallon than oil. True it burns cleaner and you can go longer between service intervals. IMO fuel costs are higher with propane but lack of service is more detrimental to oil. Ideally, if you want to prevent a "no-heat condition" then you are best served to service your boiler once a year, no matter what it burns.

There are high efficiency condensing oil boilers/furnaces on the markets capable of >90% efficiencies (not just limited to propane or natural gas). Condensing boilers/furnaces remove so much heat energy from the exhaust stream that the gases no longer have the buoyant thermal energy to rise and exhaust out of a chimney by themselves. As far as I know, these type of equipment cannot be vented into a chimney. Instead they need to be power vented (with an exhaust fan) out the side of a building with a PVC pipe. You also will need a drain installed near the boiler/furnace to carry away the condensate that forms. High efficiency condensing equipment is great provided you can pay and have room for the venting and condensate drainage. If not, then stick to less efficient equipment.

I know multiple people with cast iron gas boilers that are 30 years old and never serviced. Gas doesn't produce all the soot oil does when it burns and need to be cleaned every year.

I may be wrong, but I have never seen or heard of an oil boiler that will do 95% efficiency or even 90%.

 

[NetWareHead]

I know multiple people with cast iron gas boilers that are 30 years old and never serviced. Gas doesn't produce all the soot oil does when it burns and need to be cleaned every year.

I may be wrong, but I have never seen or heard of an oil boiler that will do 95% efficiency or even 90%.

You may not need it cleaned every year but I said it should be serviced. Two different things. Regarding a gas boiler not serviced in 30 years, well I'll just call that luck on their part. Just because it operates, doesn't mean it is operating efficiently or even safely. Most boiler techs don't charge an arm and a leg for a simple checkup. Not alot when you consider the boiler has the important job of keeping you warm in the winter. A malfunctioning boiler/furnace has the potential to kill people; whether by fire/explosion or leaking carbon monoxide. I think its a small sum to pay for peace of mind.

 

[lxskllr]

A friend of mine has a 100 year old boiler. Dunno about the efficiency, but it works well. He gets it cleaned, and checked out every year. Doesn't cost a whole lot; maybe a hundred or two.

 

[NetWareHead]

My parent's house had floor registers that used hot water.

Yeah, they suck 10x more than forced air. When forced air turns on, the room heats up quickly. With floor registers, you wait, and wait, and wait, and about an hour or two later, you might feel some warmth. Since its all radiant heat from a small area near the floor on a wall, it takes forever to warm up the room.

I'm talking about big standing cast iron radiators or baseboard convectors that are appropriately sized for the heating situation. Water and metal once they get hot, stay hot and lose their heat slowly to the room even after the demand for heat is satisfied. That's the evenness I was referring too. Its simple physics to compare the heat capacity of air vs water/metal.

I've seen those floor registers. Appropriately sized for a bathroom maybe but not for a room.

 

[skull]

Is there a reason you are not considering a heat pump with back up electric?

http://www.amana-hac.com/Products/EnergyCalculator.aspx Play with that might be worth it even if you have to upgrade your electric panel.