steam to gas conversion- pex and modern panels

adin

I am about to embark on a grand feast though I worry that my appetite is too big.



Purchased my first home- early 1900s house, solid, 1700sq'.

As a home performance contractor specializing in thermal boundary remediation, i understand the value of improving the air, vapor, and insulation barrier prior to investing in a new heating system. However, because the heating system now is a beast of steam oil boiler, and converting to gas 90+% afue will get big Gas co. rebates, I want to install new system by late summer.



The question is-   does it make sense to replace the existing boiler and the entire distribution system. I am thinking converting to to hydronic, running my own pex to new (low-end) modern panel radiators. I would hire a pro to get me started and set up the boiler and indirect dhw system.  Have about $15k to work with.



OR, should I look into converting old steam radiators to H20 or even keep steam with a new gas boiler.



Pex seems so easy....modern panel radiators so nice...cost may be deterrent.



thanks, adin

Western MA

Jamie Hall

Keep the steam

but do install a nice new more efficient boiler.  Yes, it is possible to get slightly more theoretical (I emphasize theoretical) efficiency from a modulating condensing hydronic boiler.  The difference is rarely enough to pay for tearing out the steam and putting in all new hydronic.  I -- and many (but not all) of the folks around here do not recommend trying to convert steam radiators to hot water.  There are a variety of problems associated with doing that, and for a few percent difference in efficiency, why hassle it?  Do, however, take the time and effort to get the steam system running the way it should.  That can make a huge difference.

adin

not for payback, reference ideas for maintaining steam?

Thanks Jamie,

Note that I am not looking for payback here...that is why I am insulating and air sealing the home!  the investment is for:  comfort increase, to increase house value.



What is a good reference book or site, to guide me through basic steam boiler maintenance?



cheers

Jamie Hall

The best references

are right here under "shop".  "We Got Steam Heat" is a great place to start; "The Lost Art of Steam Heating" is a really good one stop shop on what makes steam systems tick, and how to keep them running at their best.  And "Greening Steam" has some very good up to date ideas on improving overall efficiencies.



As to other questions on steam system and boiler maintenance -- this site has some of the very best pros in the business on it; in most cases you will get very fine advice on almost anything steam (or, for that matter, hydronic and radiant) you can imagine.  Just ask a question -- as you did!

Steamhead

Jamie's right- Keep the steam

tell us more about the system- is it one-pipe or two-pipe? The answer depends on whether there is just one pipe or two connected to each radiator.



And for efficient gas-fired steamers, look no further than the Smith G8 and SlantFin Intrepid in the first two pics. The best residential steamer, however, is oil-fired: the Burnham MegaSteam. That's the blue one in the third pic. Unfortunately there isn't a gas version of the MegaSteam, but the G8 and Intrepid are approved for either oil or gas.



There are plenty of good steam men in Western MA who can help you out.

The Steam Whisperer (Formerly Boilerpro)

Adding to Steamhead's comments....

One thing that the industry leaves out of efficiency numbers is electrical use.  Do some research and you'll find that Modulating/ condensing hot water boilers use significant amounts of electricity.  They need power to operate a draft fan, for most a primary boiler loop pump, a system loop pump, the boiler operating controls, and system operating controls.  On typical installations for homes like yours, you are talking about 250 to 300 watts of peak power, or rough200 to 250 watts continuous throughout the heating season.  This will go down some on light loads.  If you invest in ECM type pumps, you can probably get this down to 150 to 200 watts peak power or  120 watts continuous.   In contrast a steam boiler uses just a minuscule amount of power to operate a 40 volt amp- 24 volt transformer.  Considering that grid electricity's overall efficiency is only about 35%, with gas at least double that, you'll begin to see that inflated 95% efficiency number begin to drop quickly when taking into account all the resources used to power the heating system. 

In addition to the above, if you dig even further, you will discover that  out of the gains in reduced fuel usage of 95% mod cons, at least half or more is probably due to modulation, not condensing. 

Add in the increased complexity of mod cons and their attendant maintenance costs, and for many, shorter life, and all of a sudden you may find that steam is much less expensive to operate than the AFUE number would indicate.

Also, if you want to move to the leading edge of steam,  small modulating steam boilers can be had, if you have a good contractor.  Condensing steam boilers are already available in larger sizes and more will probably be appearing soon, but probably not by this winter.

If you want the best in comfort and efficiency, I'd add Thermostatic Radiator valves to your system and install a modulating input steam boiler. You may want to control that modulating burner with a modulating thermostat, even though I haven't tried this yet, but it should largely duplicate the operation of a coal boiler.  

I am not against  hot water mod cons ( they are about the only hot water boiler I install) but steam is much more efficient than most know.  In fact, with the addition of condensing technology to steam boilers, it is likely that steam will eclipse High efficiency hot water as the most efficient overall system when using conventional heat sources.

adin

steam it is- my infatuation with hydronic is waning

It seems steam has the respect of a wise elder.



I just ordered 'we got steam' and will connect with a trusted local pro to inquire about thermostatic controls and replacing the current system.

Still need to check if its 1 ior 2 pipe system.



So what is the most efficient DHW system with a boiler? Just a seperate gas hot water tank or on-demand to keep boiler off in warm months? This would be beneficial as we could decommision the current boiler until September install.



thanks for the input all,. As an energy auditor, having better understanding of the vast considerations when it comes to a heating system, is very useful. We encourage clients to think of their heating system to include the building envelope, distribution, and even occupant usage-  now the 'system' is becoming increasingly detailed. I look forward to the book and to further discussion.