It would be a shame to tear out the steam radiators from your 1924 house. Since the boiler is only 5 years old my suggestion is to have a steam expert evaluate the system to determine what repairs are needed. It could be a simple repair like replacing radiator valves.

Installing a furnace an the attic will be expensive. I assume the registers are currently in the ceilings, and the height is more than 8 feet. This works well for cooling, but not optimum for heating. Consider the comfort a steam system can provide in making your decision.

Yes, we've been told that it's the traps and the valves. I would like to feel more comfortable that this is a viable solution - I'd love to repair it! I agree that heat in the attic isn't ideal, and yes, the vents are in the ceilings. It's expensive to replace traps and valves too - and no guarantee that it will work? 5 rooms in our house currently don't have any heat because the traps have failed to open/close and a few of the valves are leaking.

I grew up in a house which had a one pipe steam system. The system had no traps. Each radiator had a simple shut off valve and an air vent at the opposite end.

Steam systems are very simple. Replacing the components should be relatively straight forward. You need to find someone who works on steam systems. It should not be too difficult in the Boston area.

Do you have any insulation in the attic? If not, that is something you need to do regardless of how you decide to heat your house.

Many of the problems with these systems are related to improper air and dirt separation. Have an evaluation done by true professionals that are up to date with modern hydronic heating techniques. Many improvements have been made with hydronics, it's not yesterday's technology anymore - it's tomorrow's!

SR

Here is a book worth investigating. I have never read it, but I have heard it has become the bible for those who want to understand how old steam heating systems work.

Here is a link that might be useful: The Lost Art of Steam Heating