I never had that issue. Our prior home had hot water baseboard as well. We used oil not gas. The home was about 1300 sq feet. We'd drop the temp at night to 60! (We used a programmable stat to insure the home was 68 when we got up. On rare occasion if we'd need to get up during the night...I'd raise the temp on the stat a few degrees and that woul dquickly warm the room I was in..usually the bathroom! Try it and see what happens.

You might do well to limit your setback to 5º

I have radiators, and asked the installer about this. He said it was fine but unlikely to lead to massive savings. His warning was that having colder water "hit" the boiler when it starts up in the morning may shorten the lifespan of the boiler.

It can shorten the life if it sweats a steel boiler or possibly crack a cast iron boiler.

You will always burn less fuel by setting the thermostat to a lower temp. It is kindergarten physics.

I believe that this urban legend (that you take more or the same amount of fuel to heat the place back up) developed from the problem with heat pumps. The simple thermostats used with early systems could not tell when to use backup electrical heat and gobbled up a lot of money in recovery. Some people want to hear that setback does not help because they are more comfortable at a higher temp so they accept it and pass it on enthusiastically.

Here's what an ancient plumber explained to me, but I won't swear to the validity of the explanation.

Because the radiators of old (you know, those big hulking ones that stand on the floor under every window) are exposed, i.e. people can touch them, they can't run as hot as baseboard radiators can. If you let those old, hulking radiators cool down, it takes a long time to heat them up again because you're not running very hot water through them (I forget what the guy said, maybe something like not hotter than 120 degrees; anything hotter and people would burn themselves when touching a radiator).

But baseboard radiators can run much hotter because they're protected from casual contact with people (or pets). Thus, it doesn't matter if you let them cool down at night because when you need heat, you can run 170-180 degree water through them and dump a bunch of BTUs into the room very quickly.

So perhaps the person who told you not to turn down your thermostat at night was harkening back to the days when radiators had to circulate cooler water as a safety issue, and since the water running to them had to be cooler, you were better off not letting them cool down at night because they would take a while to start putting noticeable amounts of heat into the rooms in the morning.

If you only have baseboard radiators, then I'd say turn down the heat at night and save the gas. (I even lowered the operating temperature on my boiler a little bit (i.e. lowered the temperature at which the pump starts circulating water and lowered the maximum temperature the boiler heats the water to) and saved some money without noticing any difference in how quickly the house heats up.)

it will not hurt your boiler to turn the heat down at night. I don't know if it saves all the much. keep in mind that when you turn it down 10 degrees that all objects in the home will cool down , not just the air. when you turn the heat up in the morning it might not take to long to bring the air temp up, but it takes a long time for all abject to soak up the heat and warm up. You go to set in a chair and the chair will be cold. How fast it warms up the house depends on how much radiation you have for the heat loss of the house and also what water temp you run in the boiler. Like you have been told lower boiler temp is more eff, but heats up slower. Paulbm

It may take longer to heat up again compared to a forced air furnace, but you just set your times accordingly. My radiant floor system pumps even lower temperature water than most radiators but it still has a setback system on it.

Hey I'm new here, thanks for an informative tread, I'll keep my eye out for you guys.
Keep the Home Fires Burning

Here is a link that might be useful: Which Wood Stoves ?

Many of the newer setback thermostats use a moving average method to adjust for how long the recovery takes, and then move the actual turn on time of the heat to try and hit the set time and temperature.

The heat pump type units have gotten smart enough to not use the backup heat.

You will save money over holding everything at a higher temperature.
The higher the delta t (inside to outside temperature difference) the more heat moves across the boundary.

Lowering the delta t with a setback lowers the losses.