Are there effective electric heaters for a 400 sq. ft. uninsulated rock wall room?

Fred

keyote said:

ide replace that whole mess with one high efficiency boiler and zone control what you need whether or not you put heat in the porch

Aside from that maybe being your preference, exactly why is that what he needs? Looks like a little bit of correction could be made on the near boiler piping (even though we can't see exactly what's going on there) but that can be done if/when he adds back the radiators or adds a hot water loop. He's looking for a budget friendly, non obtrusive solution to one room that only gets used occasionally. Why suggest a total, expensive maintenance heavier,system replacement?

keyote

because thats how I would do it,I didnt say he ought to should etc but if I were installing the radiators and had two boilers in one house I would get rid of that crazyness with one newer more efficient boiler, Myself included have suggested he had yet a third heating plant [stoves] to his one house. Sure I get your point another legitimate position is spend as little up front as possible, maybe you wait till one breaks down to think about it, or do you then get pulled into continuing the madness and replacing the one. I dont think its unreasonable to at this point consider the entire house which might make options in that room different. Ironically I have two boilers running now lol. But I have installed a new boiler high efficiency and am replacing the system one floor at a time myself.

shmerls

Good morning all. I've had time to review all comments to answer your questions I missed. First some overview to help you better envision what we have, had and are dealing with:

The boiler room has 2 Dunkirks. Large one for rads throughout house. Small single burner for water throughout house and apartment H20 baseboards.

2 mains come through the 2' thick boiler room wall into the garage and then branch upward into the house. The small Dunkirk goes down right from the boiler room to the apartment baseboards and over to the water tank.

The single car width long garage (entire house length) is under the dinning and living rooms which are adjacent to the Family Room (FR).

We don't find any evidence of the Mains continuing west into the apartment which is underneath the FR. Our latest assumption is that since the mains are original, and don't seem to extend to the apartment and then up to the FR, is it possible that the FR was once heated by a boiler in the apartment space before it was converted to a livable one bedroom? Otherwise to get steam to the FR, mains would need to cross through the left and right garage walls and then up, where if the boiler was under the FR, the rad pipes could go directly upward. And would explain why we can't find FR pipes off the mains in the garage and how the FR pipes were probably easily removed if only going upward and not coming all the way from the boiler room.

The only reason we're even wondering any more about how was the FR originally heated and where was the boiler and pipes, is in regard to reinstalling rad steam or water heat in the FR now. I think it's a bigger process than you guys can envision without being here and seeing where the rooms are in relation to each other and the boiler room. After all, why did we get an $18k quote? I'm sure we can get it for less, but having had back and knee surgery this year, I'm out of the running for DIY sadly.

BTW, there was a ceiling radiator in the garage which was removed but you can see the pipe and valve they left. when the boilers were converted to gas, the gas pipe runs across the ceiling where the garage ceiling rad used to mount. I'm wondering how that rad might have effected our mains in regard to someone's comment above about their mains, living space and condensate in their cement room? Currently there's no heat other than the mains in the garage but the mains are all heavily insulated so very little heat escapes. Side Note: We're thinking of adding back the garage ceiling rad since my shop is there and it's COLD!
---

@fred,
1) so there are 2 mains and neither seem to change pitch, but I haven't put a level on them. There appears to have been 4 FR rads, but only 2 plugs in one main and none in the other. Hence wondering about another boiler under the FR before the apartment was built.

2) The house is steam. The apt is water.
3) You asked for a pic of the rads. I assume you mean in the house since the FR ones we're removed and are missing. I can get you some later tonight.

@KC_Jones:
1) After we get our gas/stove quote we can do a cost benefit analysis and include windows upgrade.
2) The only aversion to reinstalling rads is the cost.
3) we will find out about a heat loss analysis.
4) mains are 90% insulated

@vaporvac
1) we are pretty sure pipes were removed. We can't find any evidence of any anywhere.
2) The FR points west as you walk into it from the living or dining rooms.
3) I'll check the sq ft plate tonight. What's EDR?

@Gordy
1) thanks for the info. It makes sense to keep the FR at a low heated level so we're not heating from no heat at all because without any heat on, the FR is as cold as the outside. So maybe we'll keep it at like 50f or so.

@BBros
the space below the FR is the apartment not the garage.

Here are some more pix to hopefully help orient you:

Gordy

You have options that is for sure.

However what temp you hold in unoccupied periods, and then bring to occupied temp desired will be experimental for you obviously. I think you will find 50 will be to much to muster in bringing the MRT to a comfortable level in occupied times.

Fred

Not to beat a dead horse but is there any possibility that a branch off of one of those mains could have crossed the garage, from left to right, above the stone walls and between the floor joists? From the seams I see in your garage ceiling, it looks like the joists run from left to right, which could accommodate piping between the joist.Do either of the current mains end with a drip leg that drops into a wet return, that looks newer than the rest of the main or do they loop back to the boiler? What size is that one plug that points upward? If it's large enough, it could have been a branch, off of the main, that fed the radiators in the FR and the plug turned down could have been a drip leg to a wet return. Do the floor joists under the FR run the same direction as the joists in the garage or do they run perpendicular to the garage?

Gordy

I really think the best solution in this situation for speedy recovery would be a Forced Air system .

The MRT would lag still, but FA would offer a faster recovery from deep setbacks.

Edit: you could use an airhandler with a fan coil off the existing steam boiler.

shmerls

@Gordy
RE: Forced Air or rads (steam or H2O), unless I'm missing some of the installation elements involved, wouldn't a nat. gas stove system be the least costly to buy and install?

My thinking/assumption is that buying/installing the 4 rads and piping, has to be more expense than 1 stove and 1 gas line, which would bypass the apartment totally, and tap into the existing gas line (garage), run through a wood window frame in the garage, then run outside the house and back into the house at the FR, meaning only one 3/4" hole thru the stone.

As much as we'd like to restore to original, it seems that becomes more of a want than a need and a costly one. With only a 3/4" gas line hole into the FR, if someday we decide to restore the house to original design, all we'd need to is plug the 3/4" hole.

I'm assuming we can find a more competitive quote than $18,000, but even still... how much cheaper can we get it? There seems to be a lot of work involved some of which we can't know what's involved until we get into it.

Cost is a factor because as new owners of a 84 year old home that wasn't fully upgraded over the years, we're finding things that need doing and thus we need to budget wisely.

Yesterday it poured a lot and we found a leak interestingly in the corner of the FR which we need to fix and don't know what's involved or thus the cost yet.

@Fred, the joists in the garage run long ways and the mains run below them. Since the apartment is finished, I can't see the joists or sheetrock screws. The only evidence of once used mains for the FR are the 2 plugs that you ask above which are both the same diameter, but I'm not home to measure. Guessing 3". Pipes off the Mains for the FR would have to run through the garage joists and possibly the apartment if parallel to the garage joists.

Bottomline. There's a bit we can't know until we break into some sheetrock to determine what's involved to re-run FR pipes. We need to keep the cost down and don't want to demo the apartment because we're using it for guests now. Plus with all we've learned thus far, it seems gas will heat with the least installation effort and demolition, and give us the stove's aesthetic look to match the vintage room/house style.

The pool table was from the house listing and not ours. Our TV is located in the same place as in the pic. Imagine a couch facing the TV where the pool table was. So, the best gas stove placement seems to be the left corner. Given the couch location,








in addition to heating the room, we'll get a fireplace!

Fred

@shmerls , kind of a moot point if you are deciding on a gas stove of some type but it sure looks like the sheet rock on the garage ceiling runs length wise in the garage which typically means the joists run from side to side.
Also, before you buy another gas appliance, make sure the gas line coming into your house is big enough to adequately supply an additional stove. If not, those costs could be way more than you are thinking.
Also, I still suspect, if you can find a path to that FR, three or four salvaged rads (that you can usually find locally at very low costs, sometimes free) re- plumbing a branch off of that main to supply those new rads may be more financially feasible than you think.

Gordy

When we try to help with solutions we try to come up with ways that will provide the best comfort, and adapt to present mechanicals in place.

If a gas stove is what your budget can afford then so be it. It is a reversible solution that may suit your needs so long as it is sized correctly.

We also have to remember that the poster may not be able to do some, or all of the work with other more involved options. So cost is going to be much higher.

Fred

Gordy said:

When we try to help with solutions we try to come up with ways that will provide the best comfort, and adapt to present mechanicals in place.

If a gas stove is what your budget can afford then so be it. It is a reversible solution that may suit your needs so long as it is sized correctly.

We also have to remember that the poster may not be able to do some, or all of the work with other more involved options. So cost is going to be much higher.

Just trying to make sure the OP looks at all the potential cost for any solution he/she might invest in. Clearly no one wants to buy a gas stove only to find out the current infrastructure won't support it and that there are significant added costs.
Making sure the Op is as informed as possible on all their options is also an important aspect of this forum. Obviously, the final decision is theirs to make. I am only hopeful this OP doesn't use the quote he has as a basis for ruling out what was originally there and what would probably work best. It doesn't require an additional boiler and all the associated additional piping/cost AND maybe additional gas supply to the house if the current boiler did, in fact, heat that room. If feasible, tying back into that system makes a lot of sense, especially since the capacity is likely already there, in that boiler. If it were me, I'd try to get one of the steam Pro's on this site to actually look it over and give the OP an honest evaluation. None of us know who provided the original quote and/or exactly what it entails. It may be legitimate; it may not be?? I'm also guessing, regardless of the selected solution, this OP will done by a contractor. Make each comparison a legitimate one.

Gordy

Fred said:

@shmerls , kind of a moot point if you are deciding on a gas stove of some type but it sure looks like the sheet rock on the garage ceiling runs length wise in the garage which typically means the joists run from side to side.
Also, before you buy another gas appliance, make sure the gas line coming into your house is big enough to adequately supply an additional stove. If not, those costs could be way more than you are thinking.
Also, I still suspect, if you can find a path to that FR, three or four salvaged rads (that you can usually find locally at very low costs, sometimes free) re- plumbing a branch off of that main to supply those new rads may be more financially feasible than you think.

In reference to the sheetrock orientation to the joist span. It is possible the joists run the length of the garage into purlin beams. Yet the drywall run their length.

It is also possible the joists were furred down to get away from protrusions allowing the drywall to run the same as the joists yet perpendicular to the furring.

However it would be more likely the joists run across the garages width.

Fred

Gordy said:

Fred said:

@shmerls , kind of a moot point if you are deciding on a gas stove of some type but it sure looks like the sheet rock on the garage ceiling runs length wise in the garage which typically means the joists run from side to side.
Also, before you buy another gas appliance, make sure the gas line coming into your house is big enough to adequately supply an additional stove. If not, those costs could be way more than you are thinking.
Also, I still suspect, if you can find a path to that FR, three or four salvaged rads (that you can usually find locally at very low costs, sometimes free) re- plumbing a branch off of that main to supply those new rads may be more financially feasible than you think.

In reference to the sheetrock orientation to the joist span. It is possible the joists run the length of the garage into purlin beams. Yet the drywall run their length.

It is also possible the joists were furred down to get away from protrusions allowing the drywall to run the same as the joists yet perpendicular to the furring.

However it would be more likely the joists run across the garages width.

Yea, I'm almost certian the joist run from side to side on that garage ceiling for a couple reasons; the garage is under the living room and dining room, the full length of the house. Purlins wouldn't have been used in that scenario and given the span, joists running that kind of span would have to have at least one center support, probably under the wall that divides the living room from the dining room. I suppose a steel beam could have been used as a center support but just wouldn't make sense when shorter, side to side joists would be much more cost effective and period correct. Anything is possible but I'm betting on side to side.

keyote

maybe instead of steam come of the hot water boiler with pex to salvaged hot water cast iron rads?

KC_Jones

shmerls said:

We got a quote to re-install radiator heat, which would require new pipes and another boiler. The quote was way too expensive.

You keep referencing this to address the suggestions we are making. Just to be clear none of us suggested a new boiler which would be a SIGNIFICANT portion of that quote you got. Also we don't discuss pricing on this site.

You have a hot water boiler and a steam boiler, both can supply a hot water system to heat that room. The hot water could be run in pex which would be similar to running wires which you already said you want to do. Question if you want to do wiring how will you do that without tearing up the apartment?

I think you need to sit down and seriously consider what everyone here is telling you. First your idea of intermittent usage and keeping the room cooler, while in theory sounds good, I don't think it will work like you expect. If you keep the room at 60, then want to bring it up to 70 you could bring the air temp up fairly quickly with some of your proposed solutions. The problem is all that stone will still be at 60 (or less) so the room would not "feel" like 70 and you would still be cold. Mean Radiant Temperature (MRT) Think of being in an unconditioned basement in the summer, feels nice and cool even if the temp isn't that low. That's what that room would feel like in the winter cold walls sucking the heat out of everything they can including your body.

To bring that stone temp up and be comfortable at 70 would take hours even days to do. If you oversize a system to be able to bring the room up fairly quickly you will probably spend as much if not more in fuel to do so versus just keeping the room at temperature all the time. As you have seen already that room will act like a heat sink against the rest of the house so you are indirectly heating it with the rest of the house, heat goes to cold always.

"we agree that Jerry probably used the room occasionally and thus since the house is a single zone, didn't want to heat the room along with the house. It's the logical explanation."
Yes except it's flawed logic.

Fred

@keyote I thought about a hot water loop also but given the Op's desire to only heat and use the room "occasionally" I was a little apprehensive about the possibility of that loop or the radiators freezing. The OP said without heat, that room is about the same temp as the outside. If they can commit to keeping that room at 55 to 60 minimum, they will be OK but old habits are sometimes hard to break, at least until a catastrophe. Even at those temps, it's still going to take hours to heat that mass and feel comfortable. It would be so much more effective to bring that room up to temp and leave it there but it is what it is.

keyote

Fred as someone said they do have to think long and hard about what they really want, we are playing with a lot of variables. If they are ok with the cost of keeping it at least moderately warm or not. as someone pointed out i dont think below 55-60 will really work. and its got a 8 foot doorway into the house and a common wall if they go beyond a stove solution, they ought to just heat it as part of the house because the house is losing heat to it anyway, and i agree the ability to bring it up to a comfortable level on short notice from outside levels may take little less energy than essentially enlarging the house by 20?%, as for up front cost pex and free radiators and a zone setup will be close to a stove and gas lines. I actually think the increased fuel usage of another water or steam zone that expands the already similarly constructed house and system some percentage compared to a roaring gas stove even a few hours a week is going to be comparable, someone could work that out for them. they certainly dont need another 18 k boiler and i wouldnt go to the steam radiator trouble but could be wrong about how much trouble it is, but someones idea about using a HX on the steam boiler for water rads might be good if its the unit with most excess capacity hey you might even see a gain in one of the boilers efficiency from an added zone. My neighbors got a quote for a six minisplit set up in three story brownstone, the number was sick i had to intervene, I sent a guy I know does excellent work over,his price was 1/3 of original bid. so one bid tells a homeowner nothing at all about cost, particularly if the owner doesnt even know what they want yet or how doing it might be acceptable to them. as someone pointed out the sheetrock issue we in the business know a carpenter can remove and reinstall those panels and clean up in a day for a days wages. we know if somehow nan owner had figured out best solution and best install routes hes going to get much better and competitive bids than asking how much to make my mansion warm, i know that area believe me so do some contractors but there ways to nip that in the bud with good info and plans

Fred

@keyote , I completely agree.

Jamie Hall

I'm very much in favour of the idea of running that space on a pair of hot water radiators -- although the radiant ceiling is attractive, too! But the beauty of the hot water is that you could run it in using PEX -- which is flexible. Which means you could do it with remarkably little disturbance. And, as @vaporvac says, you almost certainly have enough capacity in your steam boiler to do it.

Gordy

After a later pic that caught some beautiful wood on the ceilings. I think that option is out

shmerls

We met with our boiler maintenance company today to get a quote on a Mitsubishi split system. The rep's assessment is based on room size, windows (heat loss), desired heat level, we'd need 2 units plus based on the vintage style, and cost probably being just a bit less than restoring rads (water), he recommends going with rads.

He's writing up a quote covering: replace existing single burner
water boiler to handle our potable, apartment baseboards, and now 3 rads in the FR. it will obviously be separate from the steam system, have its own zone, and I gather the piping is flexible and a smaller diameter than steam and thus lighter & easier to work with and install.

@fred: I found a garage ceiling access door, opened it and you're right! The joists run perp so the pipes will run easily through the boiler wall across to the other garage/apartment wall. We won't know the joist direction until we upen the apartment ceiling up.

Even costing more, and requiring install through the Apartment, we don't want 2 split heads in the FR, or 2 condensers outside. So the split is out!

Next, we need a nat gas ventless quote and await that appointment and will decide between a gas or rad water system. We're probably going to restore the garage ceiling rad that was removed, why? We can't venture a guess. The gas line runs where the rad was positioned, so we'll have to add pipe to clear the gas line. If just adding the rad back, I'd probably take the project on. I still may. It will be a totally new learn curve and I think my back is healed up enough that with my neighbor and perhaps some help her, if I may ask? We can probably handle it & can find a used rad as one of you said earlier.

So a lot was learned, accomplished and decided today along with everyone's incredibly giving help in this thread! BTW, the heat rep today knows this forum well and reads it often!

More after the gas stove quote.

PS: the 2 holes by the West window indicate the rad was really long which he can replace, but recommends we put in 2 which he feels will be easier to locate, and obviously lighter and easier to install.

More soon...

KC_Jones

So what is wrong with the existing boiler that they are replacing it?

Brewbeer

With an internally vented natural gas heater, I'd be concerned about condensation on the interior stone surfaces, which will be quite cold in the dead of winter. When natural gas (CH4) is burned it produces (in a perfect world) one molecule of carbon dioxide (CO2) and two molecules of water (H2O), both of which are then discharged into your room. You will need to leave windows open to dissipate all that water vapor.

I also wonder whether you really need a larger hot water boiler. You said it is heating an apartment space, which presumably includes walls/ceilings/floors that have little if any heat loss due to being shared with parts of the house heated by the steam system, and it also heats domestic water. The smallest hot water boilers I've seen are about 50,000 BTUs, which may already be large enough to heat the family room and the apartment. If the hot water boiler is 100,000 BTUs, it is certainly large enough to do the job.

Can you describe a little about the apartment (sq.ft., amount of exterior wall and ceiling area, etc.) and how hot water is currently made and stored?

Fred

I'm glad you are making progress on this project and that you have found a guy who sees the benefit of replacing those Rads. Like @KC_Jones and @Brewbeer , I too am wondering why he feels there is a need to replace that boiler. How old is it? What condition is it in? Size wise, it is probably plenty big to handle the job. If condition is the issue, that may make sense. Eyes on site are usually better than what we can see. If it's an old boiler, there is some added value in addressing it along with the needed FR heating.

shmerls

Hi All. First… I sense I'm over staying my welcome and want to assure you that anything I say that seems to ignore or contract you based on my logic, is my ignorance 100% and not in any way disrespect to any of you. I really want to be clear that I am completely blown away with the time and expertise you've given Ann and me. I can't thank you enough. I've been a renter all my years and never had to deal with any of this, so it is all new and we're just trying to understand and make the best and affordable decision.

My assumptions and "logic" seems to be implying I don't agree with your input in some way. Please accept that anything out of line with your input is, again, my ignorance.

Our idea that we can keep the room at a lower than livable temp for our intermittent use is merely how we think we might use the room in Winter. Please envision that we shut the room last Winter and, me a musician and Apple tech, never wired up our stereo fully and closed the FR doors and resorted to watching "TV" on my iPad instead of that awesome Samsung screen.

From what I just read, it seems what we thought would be easy, to keep the room temp at 50-60º and easily bring it up to a comfy temp whenever we wanted to use the FR and watch TV, eat dinner, etc. because of the requirements needed to heat a rock room being totally misunderstood, it seems from the above, that we will need to keep the FR at a higher temp during Winter to keep the stones hotter as I now "get" that we're in the middle of an ice cube, and it's not "logical" (mine) or possible to heat the room quickly for occasional use.

I'm posting the labels from our 2 boilers, which I forgot to do, which I hope will fill in some important blanks. From what Bryan told us yesterday, the 37,500 water boiler won't be able to heat our potable water, apartment baseboards (which is occasional too, we've been keeping it when not occupied at 55º), and now add to the mix: 3 FR rads. There's only one burner. I'm guessing here, that if there's enough heating ability only if all 3 uses (potable water, apartment potable & heat, new FR heat) are NOT simultaneous, so to cover us when all 3 uses will be needed, we should get a larger capacity boiler, we should. Or perhaps try it with the current 37.5 boiler and see? And if it doesn't work, then replace it?

@Brewbeer - please see apartment diagram for dims.
The water is created with the small 37.5 boiler and stored in the water tank (see pix).

@KC_Jones - we are definitely seriously considering what your all are saying and can't thank you enough! We see now that our idea of keeping the FR at 50-60º when we are not using the room is not really possible because it will take too much to heat the room due to the rocks being cold and being a heat sink. We hadn't thought of the walls in that way. We get it now. Thanks! So it seems we will need to keep the FR temp higher during the Winter months. Got it.

We didn't know that either the Steam or Water boiler's could discharge hot water for a hot water rad system. Thank you. What we need to learn/determine is whether we have enough boiler output to heat the FR if we go with the water rads. If not, then what do we need to replace the 37,500 water boiler with to heat our potable water, apartment water baseboards and new FR water rads.

RE: Ventless gas: we had been told from the first we were told about ventless that they were controversial from a safety point of view and also because of the water generated as you mention. So based on the FR configuration and heat requirements, perhaps ventless heating is not going to work and if we don't want to drill the required large vent hole for a vented gas heat stove, then we may be narrowed down to water rads with no other options since we don't want splits.

@KC_Jones - you mention concerns about wiring and tearing up the apartment. Are you talking about the electrical wiring? If so, we already have that covered because there was three 220 lines for the 3 electric baseboards in the FR, which we converted to two 110 - 2 gang boxes. we couldn't get to the 3rd baseboard behind the furniture so left it for now.

Hopefully the pix an diagram will answer the various questions.

Tomorrow we are getting quotes on the ventless gas, but will now also get vented system quote, and also get a second water rad quote.

Speaking of quotes: I apologize for mentioning quotes and costs as they are not allowed here. Didn't mean to break the rules. I didn't mention the cost to get any input as to whether the quotes were reasonable, it was totally only mentioned as a comparison from water rad system to gas and as a financial feasibility bit of info as to what we can afford, versus picking any one's brain for anyone to comment on whether the quote(s) were good or not.

But if mentioning a quote for any reason is against the rules, I won't do it again. Apologies.

Here are some pix:







The apartment height is 8' 9"

Fred

@shmerls , don't feel like you have over satayed your welcome. We have some threads on here that go on for months and some that come back for more discussion a year or more later. Also, don't feel like anyone is offended by stating what you want/prefer to do to your own home. It's that input/feedback that allows everyone on here to explain what the issue/benefit of that solution might be. Clearly, you can see that there are many opinions on what each poster prefers. Some may be better than others, and these discussions allow everyone to learn/understand what we might not know ourselves. Keep coming back as long as you need to until you are comfortable that you have a solution that works for you and your lifestyle.

KC_Jones

No worries about anything, we are hear to educate to the best of our abilities, this is a great forum as you are coming to find.

I didn't read your last post in complete detail, but given that boiler output yes to do everything would be difficult that is mainly due to the potable water heating. What are you heating your hot water with now? I can't imagine it's that boiler currently is it? That is a lower output than a standard hot water heater?! If that is what you are using you might want to consider going to a standard water heater, and skip putting in a new boiler as long as the current boiler is in decent shape. That output should (I think) be enough to heat the area you are talking about. A heat loss needs to be done to be sure. Did they mention doing a heatloss? Honestly for potable water you would only need a boiler slightly larger than what you have, that's why I mention a separate water heater.

I am sure others will comment.

shmerls

@KC_Jones - The 37,500 water boiler is and has been handling both our potable water and the water 3 baseboards in the apartment and hasn't been a problem since we bought the house over a year ago.

I'm kind of remembering that the water tank is possibly why the heater works without problems. It is a Weil-McLain Plus line indirect Fired Water heater serious 3. From what our maintenance tech just told me, we have the largest home tank WM makes and it is super insulated and holds heat excellently. Plus with just myself and Ann, our use is small and thus when we do shower which is our biggest use, the boiler fills the tank back up. All I know is that in the almost 2 years here, we've never run out of hot water and then there were the couple before us who put in the system and also had a tenant in the apartment so they were 3 people then, plus the tenant used the apartment heat throughout the Winter.

@KC_Jones - The tech who's about to give us a quote for the FR water heater restoration, is doing a heat loss analysis so he can recommend the right sized boiler. He also is determining the output in regard to the chimney capacity and if not enough he'll recommend a "fan in a box" to vent the CO out of the house.

Sound good?

vaporvac

@shmerls , the method for sizing boilers is different for steam and hot water. With HW it is based on one's heatloss. There are quite a few programs to help figure that out ie. slantfin. Steam capacity it determined by the EDR of the installed rads which were originally based on the requirement to heat the house to a temp (usually 72deg) on the coldest day of the year. EDR is the square foot of steam each rad will hold; a "pick-up " factor is then added for starting the system from a cold start and heat all the cold pipes. This is the excess capacity I mentioned earlier that is used to provide a HW loop off the steam boiler. It's commonly done and in fact many people use this capacity to heat their domestic water.
It sounds complicated, but it's not. Usually the boiler states on the tag the sq ft EDR, but I don't see that on yours which is strange. It only gives the BTU input of 240k, but we can work backward to figure it out.
To measure you edr you have to have the legnth, depth and height of your rads. There are charts that then give the BTU that each rad provides. Post some pics of your rads and we can help you figure it out. With that info, we can easily calculate how much capacity you have. Most steamers are vastly oversized. If that is the case with yours, adding a loop could help mitigate some problems oversizing can cause.
However, if you're at the extreme, I tend to like @Fred 's idea of just getting a separate potable WH.

Fred

@vaporvac , That was @KC_Jones idea.

keyote

thats a big steam boiler might have capacity theres also putting the dhw on the steam and dedicating the water boiler to the two zones

Brewbeer

The family room has a heat loss of about 20-25K BTUs on a design day based on the rough calcs I posted on the first page. This is based on the stone walls and the windows having an equivalent R-factor of about 1.8. For the apartment, the layout diagram is good, but we need to know which walls are outside walls, how much insulation is in the outside walls, location and size of the windows, and whether the apartment is over or under heated space. If the apartment heat loss is 10K BTU or more, that would be pushing the limits of the existing hot water boiler, and won't be able to maintain 68 degrees in the family room on a design day, but for 80-90% of the heating season, the existing boiler is probably large enough. Hot water is not a problem since you have a large indirect tank (80 gallons?), low usage, and it is probably set up as a priority zone off the small boiler.

shmerls

Just met with new plumber. He too loves this forum! We discussed water rad system and gas system. My "latest" thinking is: we need to replace our windows if losing 30% heat. This will not be inexpensive. We want to use the FR this Winter, gas will definitely be a simpler instal and less hardware. No new boiler for one. We can use our existing gas supply and gauge. So if we look at the gas solution as an immediate temporary fix that will allow us to use the FR and upgrade the windows and then because the gas system is easily reversible, we can pull it before Winter and install a water system and boiler (having saved up from now until then), since above the FR is a deck to the sky and below is this apartment which will be insulated from the CO seeping down since heavier than air, we will be OK with this system.

Still, we are waiting for the previous contractor's quote for the water rad system, and today's contractor's water/rad system and his gas system. And then compare, with including the cost of the window replacement and see what makes the most sense with all the components in mind. A gas system totally bypasses the apartment btw.

Here are some extra pix to help:

The small water boiler:


Both the water and steam boilers:


View of the Weil-McLain tank which keeps the water hot:


Weil-McLain specs: 56 gallons:


Thanks everyone. We'll see what the quotes bring to us…

Best,
Steven and Ann

vaporvac

@shmerls , are you getting the 30% window loss from a heat loss program? I thought you already had double-pane replacement windows. How well is the perimeter of these sealed? You have a lot of window space, but I don't think you'll see enough improvement to justify the cost of replacing these replacement windows, unless they're broken. In fact, DOE reports that original windows with storms give about the same R value as double-pane replacements. Air infiltration is the killer. Is there anyway to insulate the ceiling? You can also get a big bang for your buck there. Insulating under the floor will also help quite a bit, but that would require removing the apt ceiling.
I have your exact same situation. Insulating the ceiling and under my floors made a world of difference. I have exterior and interior storms. You will always lose a lot of heat with so many large windows.
My two rads are huge. I'll measure when I get home. I think getting multiple smaller ones would probably be easier to find and transport. If getting the gas fireplace isn't to $, it may be a good stop gap measure and you can always enjoy it after you install the rads. These rooms need all the heat they can get, but they are wonderful to spend time in. I think once you're warm, it will be more than an "occasional" room.

Brewbeer

@shmerls , your existing double pane windows aren't the problem, it's the stone walls. See: https://www.archtoolbox.com/materials-systems/thermal-moisture-protection/rvalues.html

Double pane windows have an R-value of about 1.7 (1/4 inch air gap) to 2.0 (1/2 inch air gap). Triple pane windows have an R-value of 2.5 to 3. Stone has an R-value of 0.05 to 0.08 per inch, which for 24 inch thick walls, is 1.5 to 1.9.

The heat loss formula is (surface area in sq.ft.) * (temp differential between inside and outside in degrees F) / R-value = Heat Loss (BTUs/hr). The area of your walls (includes windows) is the exterior exposed perimeter times the height. Area = (18+22+18) * (8.6), which comes to approximately 500 square feet. Let's assume that the coldest day of the year is 0 F, and run some calculations to look at heat loss of various wall assemblages:

The entire wall area is stone (R=1.5):
(500)*(70)/1.5 = 23,333 BTU/hr

The entire wall area is double pane windows 1/4 inch air gap (R=1.7):
(500)*(70)/1.7 = 20,588 BTU/hr

The entire wall area is triple pane windows (R=2.5):
(500)*(70)/2.5 = 14,000 BTU/hr

Let's assume the window area is 1/3 of the total wall area. We can calculate a heat loss based on 2/3rds stone wall area (15,555 BTU/hr) and 1/3rd window wall area (6,862 for double pane, and 4,667 for triple pane). Therefore, increasing the R-value of the windows from double to triple pane has the net effect of decreasing the total wall heat loss by 2,195 BTUs/hr.

The good news is the heat loss through the floor is zero since there is heated space below. We can estimate the heat loss through the ceiling (when it is 0 F outside and 70 F inside) using an assumed R-value of 5 for the ceiling: (396) x (70) / 5 = 5,544. (You might need to adjust this based on your actual constructed assemblage).

So the heat loss of the space with double pane windows is (15,555 + 6862 + 5544) = 27,961 BTUs/hr, and 25,766 BTUs/hr with triple pane windows when it is 0 F outside and 70 F inside. As you can see, it's not significant enough to justify replacing the existing double pane windows with triple pane windows.

All these calculations can also be run in reverse to estimate the interior temperature based on a specific BTU per hour put in to the family room space by the new radiators, and a specific outdoor temperature. For example, if you put 20,000 BTUs per hour into the space while it is 20 degrees outside, you can maintain a 70 degree temp inside the room. With a 20,000 BTU input and a temp of 0 outside, you can maintain 50 degrees in the family room.

Lots of math here, but if it were my house, I would be inclined to install the radiators and connect them to the existing hot water boiler now as a separate zone, and see how you make out this winter. Seems like the boiler has enough capacity to maintain 65-70F in the family room as long at the temp doesn't drop below 15-20F outside, which for your location, isn't all that often. And when it does, you can either use an electric heater, or a blanket. Save the money you might spend on a vent-less stove, and replace the boiler next year, after you have some data about room temps over the winter.

As a side note, your stone family room has a heat loss similar to my entire house. My house costs about $1,000/year to heat, so I would expect the heating cost of your room to also be on the order of $1,000 per year.

shmerls

Hi everyone. Well the quotes are in and the cost diff is so great that we need to go with the gas stove. This way we can also do the windows which have lost their argon it seems and are a large source of heat loss. One thing at a time. As soon as we get this phase done I can get back to reading your input from last year about adding vents to our mains to balance the 2nd & 3rd floors. Can't wait to build my first antlers

Have a great weekend!
Steven

Fred

There's a new vent in the game now, the Barnes and Jones Bigmouth so don't go out and buy the Gorton #2's. The Bigmouth vents at almost twice the capacity of the Gorton #2, costs less, is all brass construction and a great vent, in general. You'll need half as many as you would with the Gortons.

shmerls

@fred. Just landed in PHX waiting our connection to San Luis Obispo, CA. Perfect time to study about heat in this gorgeous 80º weather Didn't mind leaving NY one bit. Thanks for this new vent info. Will be re-reading all the posts from last Winter to catch myself back up. Thanks. TBC...

shmerls

Ezzy and David finished installing and tweaking our new water based heating system in our rock and glass Family Room and we couldn't be happier! Ezzy and David are not just really smart about heat, but also fantastic at attention to detail that we find simply stunning. Their pipe work for example in the boiler room is a work of art. I go in there and just marvel at it and enjoy just knowing it's ours and done as professionally as you could ever imagine or wish for. What's also fantastic is that as with any project that involves judgement calls along the way, Ezzy and David came up with the best and creative solutions as to which way would be the best to go when we came to forks in the road. Again, Ann and I can't thank you all enough for recommending them. They FAR exceeded our expectations and the system works incredibly well and we finally have a 4 season Family Room versus a 3 season one. Thanks Ezzy and David.

shmerls

NEXT: I'm going to install the vents for our steam mains and rads throughout our home and then have Ezzy and David re-pipe and the steam boiler piping so that we can use the condensate for the Family room and lighten the load on our small water boiler which currently is set up on a Priority system where potable has priority over water heated baseboards. To be continued...

ratio

Thanks for the follow-up! It's especially nice to hear about a good outcome.