How to Maximize Efficiency with an old Hot Water/Steam System

Seaking Efficiency

As I mentioned in a previous topic, I have an old 1917 craftsman with steam heating pipes in the crawlspace. I am going to insulate them in the next couple weeks if possible. That will be a big step in the right direction.

Assuming they are insulated...

How much of a spread should I allow between my high and low settings? For instance, I'd like to set it to 55 low and 65 high. I'm assuming that if I set the spread too far apart, it will take too much energy to re-heat the space when I want it.

Also, how much time should I want heat to justify heating the house? For instance, it usually takes about 15 minutes to heat up the house when I turn it up from 55 to 65. If I only want heat for an hour, is that a waste?

Conversly, how much time should I NOT want heat to justify turning it down. For instance, if I'm only going to be gone for 2 hours, I'm assuming I should just leave it on. The energy needed to re-heat the pipes and house would probably be greater than maintaining.

Lastly, in looking at digital, programmable thermostats, I concluded that a Hunter 5/2 would be fine for me since my schedule isn't that varied. They appear to be cheaper than the comparable Honeywell units. I'm on a limited budget (I'm already buying a bunch of insulation remember?) and it looks like I can get a started one for about $29.99.

Any thoughts, advice or warnings are very welcome.

UPward and ONward,
Mark Bullard