Any improvements on steam heating efficiency for homes?

garfieldsimons

Time has come to put my old gas steam boiler to rest. It has served well and is ready for the eternal rest.
Is there anything coming around that can improve the efficiency of steam heating?
Richard

The Steam Whisperer

The list is long>>

1 proper boiler sizing
For conventional one pipe steam, size boiler based on radiator capacity. This is probably good for a 5 to 10 % reduction in fuel usage, could be more.
For two pipe steam, upgrade radiators to orificed supplies matched to current heating load and then match boiler to current heating load. This is probably good for a 12 to 20% reduction in fuel usage
2 insulate steam distribution piping, especially the steam mains and near boiler piping.
3 Install proper air venting on steam mains.
4 Repair steam traps if you have them. Most traps are not needed after upgrading to supply valve orifices.
5 If you have a condensate pump, make sure its necessary and if its necessary, make sure it is plumbed correctly.
6 Proper air venting of the radiators.
7 Convert to or restore naturally induced vacuum operation ( especially in most two pipe systems). One pipe systems can be converted to vacuum operation by adding a vent return line.
8 Install thermostatic radiator valves to provide room by room control of the radiators
9 Install high efficiency wet base power burner boiler.
10 Install high efficiency wet base power burner boiler with modulating burner.

Other items:

Air seal and insulate attic. On one story Chicago bungalows, this has been confirmed for about a 35% reduction in heat loss
Install Low - E glass storm windows on your conventional, original single pane windows. this has proven to save about 21% reduction in heat loss in Chicago in 1 story bungalows. This brings the u-value of windows to .3 to .36 ( r value 2.75 to 3.33) and significantly reduces overall air leakage on the home.
General air sealing around windows on the inside, electrical outlets and other wall penetrations.

Non architectural brick walls could be insulated on the outside using foam board and a Drivit ( like modern stucco) system.

Of course these building improvements will also cut your cooling costs.

Steamhead

@garfieldsimons , can you post some pics of the boiler and a few radiators? Where are you located?

The Steam Whisperer

One obvious one I didn't list is making sure your thermostat is compatible with steam heating. Correcting this alone can be a 12% reduction in fuel use.

Jamie Hall

From the standpoint of the heating system (as distinct from the envelope, which is much more important) the biggest items are right sizing the boiler, adequate venting, and making sure that everything which isn't actually heating what you want heated is insulated.

More or less in that order. If the boiler is too big, so that it cycles on pressure (or reaches too high a pressure) during a normal heating call, that's a distinct hit (it can cycle recovering from a setback -- which is one reason why setbacks, or at least ones of more than 3 or 4 degrees, are discouraged). How much of a hit is debatable, and we've been around that barn here a few times, but that it is a hit is agreed. Adequate venting is the next -- you really want the steam in your radiators, not getting squeezed somewhere. Insulation is perhaps a little less obvious, but poor or missing insulation will slow getting the steam to your radiators as much as if not more than inadequate venting.

However, in terms of bang for the buck, making sure that the envelope is tight and, to the extent reasonable or possible, insulated, is where you want to go first.

garfieldsimons

Done the calculations and new boiler will be about 15% smaller. Single zone steam, bout as simple as it gets. Replaced windows, added attic insulation, Yup got thermostat for steam. But boiler needs replacing. Putting it off for a few years is turning out to be a big mistake considering the new boiler prices. Just wondering about boiler improvements.

The Steam Whisperer

One pipe or two pipe? Also, we typically find (about 95% of the boilers we see) are about 60% oversized, so make sure to double check your calculation.

pecmsg

garfieldsimons said:

Done the calculations and new boiler will be about 15% smaller. Single zone steam, bout as simple as it gets. Replaced windows, added attic insulation, Yup got thermostat for steam. But boiler needs replacing. Putting it off for a few years is turning out to be a big mistake considering the new boiler prices. Just wondering about boiler improvements.

You’ve tighten the envelope so nows the time to reduce the EDR and that will refuse the size of the boiler. 

Greybeard

Reducing the EDR to match the building's lower heat loss might entail replacing all, or most of the radiators. Won't the existing radiation suffice, with the radiators never getting fully hot, even on the coldest days? Or is there a workaround. It isn't clear if the system is one or two pipe.

ChrisJ

Greybeard said:

Reducing the EDR to match the building's lower heat loss might entail replacing all, or most of the radiators. Won't the existing radiation suffice, with the radiators never getting fully hot, even on the coldest days? Or is there a workaround. It isn't clear if the system is one or two pipe.

Personally, I see no reason to reduce radiation.
You can reduce the boiler size, and reduce venting to balance things correctly.

pecmsg

In this area
no insulation 
horse hair plaster
when the envelope is finally insulated the EDR can be cut dramatically. 40 - 60% less. 

PMJ

ChrisJ said:

Reducing the EDR to match the building's lower heat loss might entail replacing all, or most of the radiators. Won't the existing radiation suffice, with the radiators never getting fully hot, even on the coldest days? Or is there a workaround. It isn't clear if the system is one or two pipe.

Personally, I see no reason to reduce radiation. You can reduce the boiler size, and reduce venting to balance things correctly.

You would be correct - there is no good reason to reduce radiation. It was never intended to be full of steam anyway....ever. In fact, it was intended to have a control which filled it continuously with an amount to match the current demand in real time, a demand which obviously varied a lot requiring very different fill levels.

This whole concept got lost somehow.

ethicalpaul

I agree it's probably not necessary to replace radiators. But if you did want to reduce the EDR of some of them, you can do it with covers, or with blankets