Im currently renting a home. Its an old home. I'd say at least 100 years old. windows re-done in the last 15 years or so I think. Main house is about 1010sqft 2 floors. Steam radiators on the bottom floor, nothing on the top floor. with an addition of about 300 which includes 2 radiators. Bringing total sq foot to about 1300sqft. New Steam boiler about 10 years ago, also is my hot water. Its an oil fire system and was recently seriviced (cleaned, gapped, nozle changed, filter... ect). Thermostat is in the Liveing room which is also the warmest room. Its a single zone obvioulsy single thermostat system and all the radiators are piped together. This is the first year I've lived in the home. Moved in in the spring. Recently the temps have been about 18-30 the last few days and I've used better than 5 gallons in about 24-30 hours maintaining a 62-68deg temp and using very little hot water. I know I used that much fuel because my oil delivery is about a week late and I ran out and had to fill it with a fuel can. I ran out (actually the guy cleaned my furnace on fri when i was out, and didnt turn my fuel petcock back on after changing the filter, but I was basically out of fuel at that point anyway) when I was away for a few days and returned to my home at 43deg. So the house had to warm back up. I ran out about 30 hours later. Which is now. Here are my questions.
I was told steam systems are the most efficient. Is this true?
How much oil should I use in a 24 hour period on a steam system like this in a 1300sqft house, maintaining 62-68deg regularly?
What steps should I take to better increase my fuel efficiency?