to save money by shutting off radiators

Brad White_9

the savings is not proportional. The interior walls being uninsulated and the exterior walls we hope are insulated.

Thus the loss to gain ratio of that now-unheated room is about 1:3. The fact that the interior walls are uninsulated in a way helps that now-unheated room, a bit.

Yes, the load increases on the adjacent heated rooms, sure.

But the now-unheated room has solar gains perhaps and is not going to anywhere near as cold as the outdoors anyway. It becomes a buffer space between the next heated room and the outdoors.

One also trusts that you have closed off the door to the room and slowed cross-building infiltration too.

In the end, you will save some energy, just not in proportion.

TED THE PLUMBER_2

saving money

a customer wants to shut off 2 radiators on a 1 pipe steam system. The system is in 1 unit of a 2 unit building. WHAT EFFECT WILL THAT HAVE ON FUEL COST AND SYSTEM OPERATION?

Weezbo

that is an interesting question...

it has some parameters that are outside of the perview of my crystal ball ...i will bounce it off the floor a couple times and get back with you...

Ted is this a trick question? I Hate trick questions...

one thing that might drastically affect the cost of savings is freezing the tennant or the potable water piping ...

Brad White_159

In general

the less exposed condensing surface to be heated, the less energy overall will be consumed. Same logic applies to insulating bare pipe.

Now if this is one or two out of a total of four radiators, that might cause short cycling, making the boiler seem over-sized for the load.

But if the system is properly sized (boiler output matches radiator surface in EDR) and you want to knock of 20 to 25%, I see no problem with that. You will not save 20-25% of your fuel bill though. The savings will be less. You still have to heat up the rest of the mass.

Empire_2

Brad, Might I ask you this.

Shutting down the radiators, OK but now we have an exposed room(S) on the interior of the room and little insulation between walls. Will it not pose a problem? I am comparing this with an outside parameter wall.

Mike T.

William Faust

Decreasing radiation by turning off radiators will reduce production of condensate. That may have an effect on boiler operation. Turning them off on a top floor might have less adverse result than a lower floor since condensate from the former should take longer to return to the boiler (if on).

Brad White_159

Mmmmmm.....

I think the turning off of radiators is for a longer term than just for a night or during a firing cycle, Bill. I would not worry about the loss in production of condensate because that is met by a reduction in production of steam.

ttekushan_3

boiler sizing

My opinion is that the savings tend to be proportional to the proportion of boiler size to radiation load. Confused yet? lets say the boiler happens to be a good match for the heating system. The system heats evenly and doesn't cycle on and off on high pressure during the length of most calls for heat. Shutting some radiators will give some savings as others have suggested.

If the boiler is prone to shutting down on pressure, closing radiators will cause excessive boiler cycling, wasting energy. Do enough of this, seasonal losses on the heating plant can negate the short cycle savings. Especially if a building thermostat is housed in a room adjacent to the now unheated space. The uninsulated wall increases the load on the heated room, effectively reducing the size of the radiation, causing more frequent calls for heat.

So go to the basement with the system running and see if the boiler shuts off on pressure during an average heating cycle (you don't have that pressure set too high, do you?).

If it doesn't, you're probably saving roughly half of what you're expecting. Which isn't much, but might be worth it. If the boiler begins short cycling on pressure, then you aren't saving a dime over the season.

The unlikely exception would be a forced draft steam boiler with at least two firing levels. I've worked with a number of them, and they're wonderful. You might even be able to save energy nearly in proportion to radiator closure.

I mean no offense by this next statement, just an observation.

Building owners who are cheap enough to order the shutting of one or two radiators in a large building are also cheap enough to NEVER own the kind of boilers or perform the kind of maintenance that would save them huge sums of money in the long run.

So I doubt you have anything this sophisticated in the boiler room.