One pipe steam, New addition, what to do...

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. And two, I don't have any spare radiators and the cost even in the aftermarket of used radiators is high!







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.





Lastly, the folks on the diyforum that recommended I come here and ask questions,  have told me my boiler can be plumbed to do both steam and forced hot water at the same time. However, I'm weary that a call for heat in a forced hot water zone would also create steam in a steam zone not calling for heat.







Advise from the pros ?



Thanks!!



-- Joe