I have a 3 story 3 fam with separate utilities and the 2nd floor boiler need replacement in the near future.. Its stamped 1981, and there are burn marks on the outside of it.. The tenants are seeing high gas bills just to keep 1000 SQ FT of livings space at 62 deg. Looking at high efficiency gas boiler since there is $1500 rebate on 95% products, but I see these old boilers last for 30 years.. Are the new high efficiency boilers just as reliable? And should I get a combination boiler and domestic hot water combined, or keep separate for easier maintenance. I am taking a long view of this purchase, so don't want to think about it for 10+ years...
thanks in advance for any insight.
@Joe Kato I seriously doubt that your boiler is just providing less heat as a sign of failing, that not a symptom that I've experienced. It could be out of adjustment or the burners can be sooted up (burns inefficiently). The piping could be air locked (no hot water circulating). Circulating pump could be bad (again no hot water circulating). Fins on the heaters clogged with lint and grease (no transfer of heat from water to the air). You should have a qualified boiler person service the unit. Be sure to tell them exactly what's going on. A boiler is actually a fairly simple device (fire on tubes of water) and I have not experienced them just sort of trailing off with heat output. I have a boiler that is gas fired that was converted from coal to gas by sticking a gas burner in it. I would guess it is pushing 100 years. I have others in the 40-50 year range. In lots of cases they last a very long time. I'm sure they will fail some day but when they do, I expect they will just stop working altogether. They might leak but that would certainly be visible and unless it's a boat load of water it wouldn't reduce the heat output.
The smoke on the exterior of the unit is from poor ignition which might be due to starving for combustion air (no fresh air supply in a small utility room) or the improper adjustment I mentioned before.
@Joe Kato I seriously doubt that your boiler is just providing less heat as a sign of failing, that not a symptom that I've experienced. It could be out of adjustment or the burners can be sooted up (burns inefficiently). The piping could be air locked (no hot water circulating). Circulating pump could be bad (again no hot water circulating). Fins on the heaters clogged with lint and grease (no transfer of heat from water to the air). You should have a qualified boiler person service the unit. Be sure to tell them exactly what's going on. A boiler is actually a fairly simple device (fire on tubes of water) and I have not experienced them just sort of trailing off with heat output. I have a boiler that is gas fired that was converted from coal to gas by sticking a gas burner in it. I would guess it is pushing 100 years. I have others in the 40-50 year range. In lots of cases they last a very long time. I'm sure they will fail some day but when they do, I expect they will just stop working altogether. They might leak but that would certainly be visible and unless it's a boat load of water it wouldn't reduce the heat output.
The smoke on the exterior of the unit is from poor ignition which might be due to starving for combustion air (no fresh air supply in a small utility room) or the improper adjustment I mentioned before.
Have it serviced and look to the circulating pump if they can only get it to 62. I found that our boiler wasn't heating part of the house because of bad circulating pump. If the pipes are cold in one are area that is usually the cause. Maybe you want to replace it but you have some winter left see if servicing it gets it up to speed. If you need to replace it I would also get on water on this system. I think it will probably be cost effective addition.
Didn't mean to imply it only gets to 62 deg.. It can get warmer than that. But a $200+ gas bill for a month seems high when apartment is kept at low 60s.. I like the incentive to change to a high efficiency gas boiler. But worry if the old style boilers are more reliable than new 95% boilers? I guess I should get some HVAC pro opinions but most people I talk to have an opinion or favorite brand and haven't met many people that know unbiased data or scientific results.
@Colleen F. See you are in Narragansett.. Any good MFR cash flows in your area? Any MFR for sale?
I went through the same issue a couple of years ago. Previous owner had a oil boiler that serviced all 3 units in a 3 family and was paying upwards of $3500 a year in oil. I went the conventional route for durability and ease of maintenance. Those fancy combination units break down a lot and if you don't have an experienced tech installing them they won't last long.
Before Pictures of Boiler and Water Tank:
After much discussion with HVAC and a Plumber I decided on installing 3 separate metered conventional natural gas boilers. They would be connected to the already Natural Gas meters located on the property that serviced the tenants cooking needs. We eliminated the continuous one loop and installed 3 loops, one for each tenant. The first floor received all new baseboard since we were in the process of renovating that unit fully. The second and third floors, we tapped into the existing piping and cast iron radiators located in their units from the basement.
We eliminated as much cast iron and copper we could from the basement and replaced it with Trac pipe for the gas supply and PEX for all the supply and return lines.
After Pictures of Boilers and Water Tanks:
I spent about $9-10k in just material and about ~$3k in labor. I also redid all the plumbing in the basement so hard to nail down the exact labor cost. I kept my boilers in the basement due to space constraints for the 2nd and 3rd floor. I also kept the existing cast iron radiators as I didn't want to intrude too much on the tenants currently living there.
george, that looks amazing.
i know nothing about boilers, but i'd just call a few commercial stores and just ask them which one is the best. when i changed the water heater to my house with an instant water heater i called around and found out that Noritz is the best (what i was told). so i just got that and installed it my self.
I think @Bill S. hit on your issue of the system being air locked. You have to periodically "bleed" radiators in order to keep the air out. When the water cannot circulate, that's when the radiators get cold.
While you are at it bleeding that one unit, you might as well chech on the other two units too.
If you do a replacement, I highly suggest getting a separate hot water heater. The winter-summer hook-ups on the combined system are a hassle for the landlord since tenants usually can't figure out how they are supposed to operate.
One other issue that Bill mentioned is lack of air intake for combustion. This can be a dangerous situation since intake air for combustion can then start being pulled in via the chimney / exhaust; that also starts to hamper or even suck in exhaust gases. It is a more common occurence when many burner units are installed within the same utility room area. There is something called an air make up kit that can be installed to bring additional outside air in for support of proper combustion. Skuttle is a brand that I have used for this.
The high efficiency units are direct venting and will each have to have their own intake and exhaust piping through the wall using PVC; that would solve the problem of lack of air for combustion.
@George Paiva and Others - I have nothing to add but I wanted to thank you all for your contribution to the community. Your replies took some effort and are greatly appreciated.
You guys are the reason I check in everyday.
The best solution...
in fact we just put one in a friends SFR. But it was a pita retrofitting the new unit into the existing decrepit piping etc. New fittings to do so ran >$425.
Also be prepared for some downtime. Our HVAC friend was able to expedite the work with a hydraulic copper piping crimping tool but that kit costs around $2000. But it still took about 12 hours for amateurs like us to complete. I would definitely make sure the guy you use is an experienced installer to avoid problems & reduce costs.
The air locks previously mentioned are an issue as is the need to 'balance' the system. Also don't neglect cleaning all the rad fins as we found this last one coated with dust & dog hair etc etc.
George P. Nice work!
After talking with others, I think I am staying with the old style 85% eff boilers. I hear new 95% ones need a yearly cleaning and more maintenance. Even converting my one oil boiler to gas using Carlin Combustion GasPro would cost as much as just buying a gas boiler
http://www.pexsupply.com/Weil-Mclain-381-357-800-CGA-25-38000-BTU-Output-Boiler-Spark-Ignition-Nat-Gas
As for my burnt boiler... its a Remco from 1981... will try to work new boiler into lease extension..
Yep I researched and talked to all the pro's including the supply houses. They all said go conventional and keep it separated from heater for radiators and heater for water. Conventional lasts for a long time and doesn't require a lot of tweaks to have them maintained. Of course I had a full basement for all this so be wary of what @Steve Babiak indicated with air input. Also the exhaust will have to be taken care of as well. I had to put in a chimney liner.
@Account Closed well if you have the space to run the duckwork or eventually put a forced air in unit to avoid unnecessary runs of duct work from basement then fine. But also need to mention the $$$ and headache of taking out the supply and return lines as well as radiators. I would also mention the hot water radiators keep the heat longer vs forced air.
There's a lot to contend with assuming OP has a boiler now and only wants to swap out a boiler without disturbing the radiators and supply lines currently.
Now if we are talking blank slate I would do forced air all day long as its cheaper for the unit and running the duct work.
a new boiler is quite expensive, a forced air unit about 25 percent of the price, which is why after scraping or sellin the radiators, a forced air system might no t be a bad idea. The gas is already there, just run the trunk and the flex line (if possible) are go hard trunk all the way. Pay the few dollars extra and get rid if the headache. That's just me though.
I would think about furnace, but this is 3 story with existing baseboard radiators on 2 floors. Has been installed for many years..current boiler is 1981.. No hassle in my time owning it. I think I am not going to mess with anything this year, no enticing rebates are going to get me to change to 95% efficient...
Many new gas boilers don't have domestic coils, therefore you can shut down the boiler in the non-heating months and just run the gas hot water heater.
We've done both oil to gas conversions as well as hot water to hot air. with the hot air you get the option of adding central air which can be a big selling/renting point, depending on your area and price point.
There's one more option for heat & HW: using an indirect tank as a zone off a cold starting conventional boiler. The advantages include higher efficiency and lower standby losses than conventional WH, and the indirect is dead simple and will last forever unlike conventional tanks. In summer the boiler will fire and heat the tank, but then go cold till water is actually used. And since the tank has no flue to vent the heat up, it only loses 1/4 deg/hr. The boiler won't fire from morning showers til someone comes home and uses hot water.
I just went through this about 3 months ago. I had two units in my building where the heat would not go above about 70 degrees. And this was before the whole polar vortex thing. I had two different HVAC people look at it. They both told me the same thing. Replace them. They purged all the air out of system and flushed in fresh water. No matter what my tenants could not keep their apartments warm and the boilers ran constantly. They were each about 30 years old. After $8900 bucks worth of work I now have a setup very similar to what @George Paiva has. No more heating issues. I think what was explained to me is that over time there is calcification that takes place inside the coil where the burner is at. And overtime time you just loose more and more thermal capacity or transfer.
in all the homes I buy there is one thing I always do that helps this problems. It is relatively inexpensive, typically need no maintenance! and will last a very long time. Add some insulation to the home. I have bought two homes in the last year that had no wall insulation. I went through $800 of oil in less than 1 month. After A couple holes in the walls and now a conversion to gas, I will insulate the home at a cost of $3600 and now repair all the plaster walls.
But even newer homes I add additional insulation. Have a insulation installer let you know what could be done to reduce heating costs. 65% of heat loss is through the top floor ceiling. It is obviousness , increase attic insulation. Even though you are burning a fossil fuel, in new homes, basement ceilings still must be insulated. The ventilation of the attic is just as important in the summertime as well.
Today had R-50 insulation blown in attic, did another one like that last fall. Energy costs will go up, so adding extra insulation is a good long term investment. The standard here for new construction attics is R-38, so we're exceeding new standard.
Today had R-50 insulation blown in attic, did another one like that last fall. Energy costs will go up, so adding extra insulation is a good long term investment. The standard here for new construction attics is R-38, so we're exceeding new standard.
Dave,
I agree, energy costs are only headed in one direction and current building codes are woefully inadequate where energy efficiency is concerned.
We have set objectives for our retrofits of R75-R100 in attics and R28 - R50 in walls (where cavity space allows).
Dave,
I agree, energy costs are only headed in one direction and current building codes are woefully inadequate where energy efficiency is concerned.
We have set objectives for our retrofits of R75-R100 in attics and R28 - R50 in walls (where cavity space allows).
Wow, up north I can't believe the insulation standards. How do you achieve a R-75-100. Three layers of 9 1/2" R-30?
Another thing I do in all my homes is I always take the OIL system out and replace it with natural gas if available. If not I change to a heat pump. I do not like oil. It is dirty, smelly and expensive.
Martin:
Sadly the minimum building code for in Canada only requires R20 insulation wall cavities and does not require measures be taken to mitigate thermal bridging. As such a "to code" 2x6 stick framed wall could only have an effective thermal resistance of R12 to R14.
Similarly attic insulation only need provide an RSi of 6.5 (~R40) to meet minimum code for new builds, though several provinces and territories are encouraging a minimum of R50, I do not believe any have made it mandatory as of yet. Furthermore, any housing stock 30+ years could likely have <=R24 unless it had been improved over the years.
To achieve R28+ in walls requires use of a material such as closed cell foam (~R6 - R6.5/inch) or polyisocyanurate hardboard (~R7 - R7.6/inch). There are new vacuum insulated panel technologies coming available which claim R20+/inch, however they are not yet cost effective, nor are builders familiar with their use and installation {puncture one and it goes from R20 to zero}.
To achieve R75 to R100 in an attic requires 18 - 28 inches of mineral wool / fibreglass batts or the same of blown cellulose. In some of our really old buildings (Victorian, Edwardian) it makes more sense to insulate the underside of the roof deck using closed cell foam and then place polyisocyanuarate hard board on the topside of the deck with a piggyback roof over top. The quality of the air sealing is also a big factor ... if there is a draft, then 18" of batt or blown insulation makes a good filter, but marginal insulation.
Amen to Roy about air sealing. Tons of insulation is lovely, but going up in the attic with a can of foam (fireblock foam where called for) and a tube of caulk is crucial. If you're working on an old house, you'll be amazed at how leaky the building envelope is - plumbing chases, electrical boxes, top plates, etc.