Current steam, Future Electric or Hydronic?

anesthes

My house was built in 1945. I have a steam system, one pipe, gravity drain back. I have currently 5 radiators covering 900 square feet on a over-fired peerless wbv-03 boiler. (oil fired). I have it set up with now with a nozzle and such that it's around 85,000 BTU if I recall (within mfg specs).

So anyway, I built an addition, roughly 620 square feet which equates to two new bedrooms, and a new mater bath.

My boiler has the capacity to heat the additional space, however due to the construction I can't really put steam radiators in the new part of the house. For one, the ceiling joists are much lower than the other part of the basement, so there is no real way to provide a gravity drain back to the boiler.

So I have a few options. I've been investigating electric baseboards. We pay .14 cents per kwh here in New Hampshire, which means 1 million btu is about $41.52 at an efficiency rating of 99%.

In contrast, my oil furnace is around 83% efficient and costs about $30.32 per million btu. (Oil is around $3.50 per gallon today).

Now, another option I have is converting to a forced hot water system. My boiler, when used with forced hot water according to mfg specs, can achieve a higher efficiency rating of around 87%, which would translate to roughly $28.92 per million BTU.

Now, I'm not an expert at converting, but I roughly figured out the following and here is where I need help. If I convert the boiler/system to forced hot water I need the following I think:

Baseboards $450
Circulator pump $200
Aquastat $100
Zone valves $300
Piping $400
Expansion tank $100
Thermostats $100
Zone Valves $225

Total $1,875

This assumes 8 or 9 baseboards, 3 'zones'. I'm assuming 1 circulator pump and 3 valves are what is needed. Pex tubing, misc fittings, etc.

The alternate option of electricity is:

Baseboards $450
Wire $125
Breakers $75
Thermostats $540
Misc electrical supplies $40

Total: $1,230

I could also cut that in half and just run electric in the addition, but then I would be heating with *two* systems.


Advise from the pros ?

-- Joe

anesthes

Really, nobody?

-- Joe

beenthere

Your steam boiler can also provide hot water for hot water baseboards.

Leah Frances

I would do some reading at http://www.heatinghelp.com They are really helpful about hydrionic heat.

I think your choice is probably a crap-shoot. One way or the other; energy is going to cost something.

Personally, I really like how my single-pipe steam feels, and I am willing to live with the 83% and the oil costs because it heats up lickety-split and doesn't require long heating cycles to warm the house up. I am adding some mini-split ACs with heat pumps to supplement or add where the former homeowner took the rads out () I've got solid masonry walls = no where for pipes or ducts.

Good luck.
Leah

__________________
If I could only remember to THINK about what I was doing before I did it.

anesthes

Do you mean through the auxiliary water port?

I wish I knew more about this stuff. The first thing that comes to mind is, can it maintain the volume of water required and where does the water go when not circulating?

-- Joe

beenthere

All the boiler piping is done below the water line. So all the water stays in the loop, it doesn't drain back to the boiler.

anesthes

Oh you are talking about circulating through the boiler itself. I thought you meant the aux water heater on the side (that some folks use to pre-heat a water heater).

Are you suggesting using the boiler for both steam and hydronic at the same time ?? Wouldn't the water get too hot (i.e, boil) ?

-- Joe

beenthere

Yes, the boilers water, not the tankless coils water. The water won't get too hot when piped up properly.

anesthes

But it would still be able to create steam for the rest of the house??

Hrmm.. Interesting.. I'll have to read the manual on my boiler again.

-- Joe

beenthere

Yes. Its semi common to have a steam boiler provide both steam and hot water at the same time.

The piping for the water is done so that return water from the baseboard is mixed in with the hot water from the boiler to protect the circulator from over heating.

anesthes

Hrmm. And my actual model can support that? I will have to do some more research, perhaps contact peerless or a boiler specialist.

My steam system is a one pipe. If for example, a bedroom that is hydronic calls for heat, how would you keep the steam system from heating?

-- Joe

beenthere

Yes, your boiler/actual model can be piped to supply both.

For the hydronic heat, a separate aquastat is installed, and set to a temp low enough not to make vapor or steam. Usually 180°F or less, depending on how much baseboard is in the area you want to heat, compared to how much heat that area needs.