Harman PB 105 Boiler/ Harman 100 Furnace - Help Please?

[dssamuels]

I have a few questions between the Harman pb105 boiler and the Harman pellet furnace that I was hoping people could help with.

I have a 2600 square foot colonial home that currently is heated (and domestic hot water) by an oil boiler with 4 zone baseboard radiator heat. I also have a separate AC duct system. The duct system is actually a two zone system so there is completely separate ducts for the upstairs and downstairs.

I am trying to decide which unit (the boiler or the furnace is better for my application)

If I get the furnace and hook it to the downstairs AC duct system, will it effectively heat the upstairs? There are ducts in every room including the hallways downstairs? I do not believe that I will be able to hook it into both the upstairs and downstairs ac duct systems.

The furnace is aproximately $3400.00 plus install. If I use this unit, I will still use oil for the domestic hot water is the warmer months and the 30 year old oil boiler will serve as a back-up

If I get the boiler, I can hook it into the existing 4 zone heating system and I guess it can also do the domestic hot water if I get the coil. The 30 year old oil boiler will still serve as a back-up. This unit is $6600.00 (with the water coil)($6400 without it) plus install.

I am being told that if I get the harman boiler system, I will still need to keep a functioning oil back-up system. Being that my current system is 30 years old, I will likely end up buying the pellet boiler and the oil boiler. Though, even if I get the furnace, I may end up having to get a new oil boiler system when mine goes.????

So, I could really use some help in deciding which is the better route to go?

Is it cost effective to use the domestic hot water coil on the pellett boiler over the oil boiler. (Burn efficiency, etc.)?

Will I really recoup the additional $3000 by using the boiler, making it worthwhile? It seems that if the furnace could do the job (in the ac unit to the downstairs) and it is not worth $$$ to use the domestic coil on the pellet boiler that it may not be worth the additional money for the boiler????

As you can see, I need a lot of help.

Do you think the furnace will do the job to keep the upstairs bedrooms/bathroom warm? We need to keep the upstairs warm in the winter 69-70 degrees for the kids so I am a little nervous that just going through the vents downstairs (without installing fans) will do the job. Thoughts please???

Is the domestic hot water coil really beneficial to save money and continued use of oil to justify the extra $3000 for the boiler? Obviously, it will get us to stop using the oil, but are we really going to be saving enough money to make it worthwhile?? Again, the burn efficiency for the draw of the hot water, etc,??

Which route would you go and why??? I am trying to make the purchase this week so any and all help is much appreciated.

Thanks

Dave Samuels

 

[Nofossil]

I might consider waiting just a bit before jumping into this. There are a few things that would help:

1) What is your oil consumption now?

2) What will it cost you for pellets?

There's no way to even guess at payback without knowing at least that much.

I don't know about code and local dealer experience, but there are very small and relatively inexpensive direct vent gas and oil boilers that might be a more cost-effective solution for backup and hot water. I recently bought a Takagi tankless water heater for under $500 that's rated for 190,000 BTU/hr. The manufacturer recommends it for space heating as well as hot water. The coil-in-boiler approach wastes a lot of heat during spring, summer, and fall.

 

[dssamuels]

Thanks Nofossil.

1. I am using 1000 gallons of oil per year. Oil prices right now are quoted at $4.40 per gallon.
2. Pellets are $220 per ton delivered.

I am estimating 5-8 tons for the winter and another 5 for the remainder of the year if I use the boiler. Sound about right? Obviously, if I run the furnace, then I will also be using oil to heat the hot water.

What I am struggling with is whether the furnace, which would vent through the AC duct system for the downstairs only would get the heat upstairs adequately and without the use of fans. There are vents in every room and the hallway downstairs. Obviously, this would be forced air through the AC ducts.

The boiler would hook into the central heating baseboad radiators so I know the heat would reach all ther rooms - similar to the oil set-up. But the boiler unit is $3000 more installed. Sounds like running the coil-in-burner approach is not really cost effective from what you are saying? If this is the case and the heat will get to the upstairs, it may pay to get the furnace for the $3000 that I would save over the pellet boiler?

What do you think? I can really use the guidance. Any and all suggestions are really appreciated.

Thanks,

Dave

 

[Nofossil]

Thanks Nofossil.

1. I am using 1000 gallons of oil per year. Oil prices right now are quoted at $4.40 per gallon.
2. Pellets are $220 per ton delivered.

I am estimating 5-8 tons for the winter and another 5 for the remainder of the year if I use the boiler. Sound about right? Obviously, if I run the furnace, then I will also be using oil to heat the hot water.

What I am struggling with is whether the furnace, which would vent through the AC duct system for the downstairs only would get the heat upstairs adequately and without the use of fans. There are vents in every room and the hallway downstairs. Obviously, this would be forced air through the AC ducts.

The boiler would hook into the central heating baseboad radiators so I know the heat would reach all ther rooms - similar to the oil set-up. But the boiler unit is $3000 more installed. Sounds like running the coil-in-burner approach is not really cost effective from what you are saying? If this is the case and the heat will get to the upstairs, it may pay to get the furnace for the $3000 that I would save over the pellet boiler?

What do you think? I can really use the guidance. Any and all suggestions are really appreciated.

Thanks,

Dave

My rough analysis is that you would burn 8 cords to replace your 1000 gallons of oil IF the wood furnace were the same efficiency as the oil furnace. I don't know efficiency numbers for pellet furnaces. If those numbers are about right, you would save $2600 per year. My prejudice is in favor of the hydronic approach rather than the hot air. You know it will do the job.

I'd consider the pellet boiler for now, and perhaps a tankless water heater for hot water and backup at some point in the future. The tankless will save you something like 50% or more during the summer and shoulder seasons.

 

[sinnian]

My rough analysis is that you would burn 8 cords to replace your 1000 gallons of oil IF the wood furnace were the same efficiency as the oil furnace. I don't know efficiency numbers for pellet furnaces. If those numbers are about right, you would save $2600 per year. My prejudice is in favor of the hydronic approach rather than the hot air. You know it will do the job.

I'd consider the pellet boiler for now, and perhaps a tankless water heater for hot water and backup at some point in the future. The tankless will save you something like 50% or more during the summer and shoulder seasons.

http://www.maineenergysystems.com/savings_calculator.htm

About 7 1/2 tons of pellets. However, if you did not have to keep your DHW temperature up all the time, using an indirect hot water tank, 'I have been told' that equates to about a tank of oil. Therefore you could shave off another 2 tons possibly.

 

[dssamuels]

Sorry, I am a little slow on the uptake. Are you saying that if I use an indirect hot water tank, it saves approximately 1 tank of oil, and therefore, I can shave off 2 more tons possibly?

Thanks

 

[sinnian]

That is what I have been led to believe. Hopefully, someone else will comment on this.

 

[Nofossil]

Sorry, I am a little slow on the uptake. Are you saying that if I use an indirect hot water tank, it saves approximately 1 tank of oil, and therefore, I can shave off 2 more tons possibly?

Thanks

My guess would be closer to a half tank savings per year - at current prices, $500 or $600 in oil savings. Indirect tanks have extremely low standby losses compared to coil-in-boiler systems. Also, they hold more water so you can fire the heat source less often. I heat my indirect with wood during the winter, solar during the summer, and soon, with a tankless hot water heater when I have a few cloudy days in a row.

 

[sinnian]

My guess would be closer to a half tank savings per year - at current prices, $500 or $600 in oil savings. Indirect tanks have extremely low standby losses compared to coil-in-boiler systems. Also, they hold more water so you can fire the heat source less often. I heat my indirect with wood during the winter, solar during the summer, and soon, with a tankless hot water heater when I have a few cloudy days in a row.

So about 1 ton less / savings then.

 

[Willman]

Sorry, I am a little slow on the uptake. Are you saying that if I use an indirect hot water tank, it saves approximately 1 tank of oil, and therefore, I can shave off 2 more tons possibly?

Thanks

A good way to determine oil usage is to ascertain the nozzle size. If it is 1 GPH that means it burns a g every hour. In summer if your boiler is not a cold start it has to run to maintain a set temp. Its know as standby. If no hot water is used and it runs 1 hour a day that is 1 gal. Add in DHW usage and run time goes up. Even with an indirect boiler still needs to stay hot. Beings you have a boiler all set up and functional zoning I would bite the bullet and go the extra. It will pay you back. No need to try to figure if using the ac ducting to deliver heat would work or not. Which IMHO ac is sized and registers located for ac and not heat. If you save 1 tank @ $4.00+ a g that would help in the payback.
Will

 

[stephenmoore]

I have a PB 105 with the domestic coil to pre heat my hot water to my stainless elctric heater. My house is about 2400 sq feet. I burn two bags a day to keep the entire home at 72 farenheit. I have 5 zones of in floor slab radiant, 2 zones of in joist, and one high temo convector rad zone. Ask your dealer about the reliability of the igniters in the Harmon. I am on my 5th one in less than a year. The only reply I get is they had a bad batch .. Sounds fishy to me. For $6600 it shouldn't calve five times in the first season. Hope this helps.