Switching Rads to Radiant floor

TheKeymaster

Some background. I was a contractor once upon a time, but I got older and went back to school so I wasn't swinging a hammer at 65. Now I work for an architecture firm. That makes me a pretty good DIYer at this stage of my life.

My wife and I are buying a house built in 1910 (about 3600sqft) that has radiators(hot water not steam,all in good working in use shape). I'll be ripping up a lot of the house, so I thought about changing the radiators out for hot water floor heat while I have access. Mostly because the house has so many doors, giant windows, mantles that I thought eliminating the radiators might make it easier to layout rooms for furniture and also be more comfortable. I'll be tied up with so many other repairs that I really don't want to do this part of the job. Also since I've never done much HVAC in my years and I have enough experience to know when to not DIY something that I'm not familiar with to try and save a buck. Can anyone recommend a good plumber installer in my area that will do heat calculations and whatever else needs done so I don't end up with freezing rooms or sauna rooms? The house will be on the East side of Pittsburgh ,PA. The house is solid masonry with brick face up to the second floor then frame brick faced on the third floor. I thought the floor heat would help because there is not a good or easy way for me to add any insulation besides on the third floor where I will be adding it. Windows are obviously old, but most in great shape. No storm windows, but also I didn't notice any air leakage either. A few bad windows will get replaced now and the rest little by little, but more pending projects need attention first, like two bathrooms still have wood toilet tanks.

Another question I have is that the radiators are in great shape and not all gunked up with paint. They almost all seem to have only the original coating on them. They are also ornate. I can't find a name for the style besides a few references to Victorian. A few different sizes and shapes but they all are the same style. I think about 15-19 total but I didn't get a count. I'd love to sell them as a lot to offset some of the cost of switching over. I know I can sell them individual at more of a retail price and make more money, but I'd be fine selling them more as a whole sale lot for a fair price to an architectural salvage sort of company. Does anyone know of such a company that would be interested? I've tried around my area with no luck so far. Some people said I should try more north to see if I can find a company up there. I'd even be willing to deliver them a couple states away if I got a decent price for the lot.

hot_rod

The first step in any heating project is to perform a room by room heat load calculator.

Find free calculators at SlantFin or US boiler websites.

Then you can determine if radiant cn cover the heating loads in the various rooms without supplemental heat emitters.

Any way that you would reuse those radiators with new piping, maybe a homerun pex line to each location?

Ironman

I totally agree that a heat loss calc is your first and foremost step. Everything builds upon that.

Don't be surprised if a radiant floor cannot supply enough heat by itself. Staple up with good heat transfer plates can provide about 18 - 20 btus per sq. foot. A house like yours probably needs north of 30 btus per sq. foot

Old cast iron rads can be very efficient and comfortable when property married to a mod/con boiler.

Harvey Ramer is in Chambersburg. Find him on the contractor locator.

Rich_49

Harvey Ramer .

TheKeymaster

@Hotrod The radiators are all still being used so I could reuse any of them. We were just trying to create some more wall area for furniture. Would running new lines to them have any benefit? I guess if it was a home run line then I could zone them? I assume they are all just on one zone now. I've done minor repairs to forced air but I know jack about hot water heat.

@Ironman I didn't realize that radiant floor might not be enough. That's something I didn't even consider. Ceilings are high and I'm sure the solid masonry walls are cold to the touch. I believe the plaster is right on the blocks. House is solid as %$## and that's why it's a great reno for our forever home(great bones), but a pain to run electric and other stuff. What is a mod/con boiler? modern? conventional? The boiler is old and has a few years left. Would it be a big savings overall to replace a 20-30 year old boiler with a new model? I'm not sure it's exact age. The previous owners say they still have it serviced by the company that installed it. I might call them and see if they have records back that far to get an install date.

Chambersburg is pretty far from me. Probably why it didn't show up on the finder. I see Ray Wohlfarth is in Pittsburgh from reading the forum, but they don't do installs anymore from what I see. I was thinking of emailing him and asking him for a recommendation also.

The calculators will be a good start. I didn't know where to start and that's why I'm asking questions. I didn't want to get a guy over to give me a bid and when he asks what I'm looking for, I just shrug.

hot_rod

The best money would be spent tightening up the home, adding insulation if possible. Getting the load numbers as low as possible pays off in fuel cost from now on. The load calc, maybe a blower door test on your home would be the best data to gather.

In that type of construction you may not be able to get R values like you see in new construction.

A good energy analysis and walk through from a pro would shed a lot of light on your project.

The cals can be done by DIYers, but an energy pro knows where to look and what to look for, it might be money well spent this early in the project.

Jamie Hall

A couple of items... on the windows. Don't replace them. Have them tightened up and adjusted a bit -- not a bad job for DIY, by the way -- and use good storm windows, either outside or inside. Much better and cheaper.

A Mod/con is short for "modulating and condensing". They are the highest efficiency boilers which can be had for hot water heat. However, they do need to be carefully installed, and the controls carefully calibrated, to get the most out of them.

Unless you absolutely positively have to have the extra space which getting rid of the radiators would give you, I wouldn't do it. First off, as noted the radiant floors may not give you enough heat. Second, they are there... and there are few things as comfortable as a nice warm radiator! Third, they may well have the capacity needed to take real advantage of a mod/con boiler -- but to find that out you will need to do a good heat loss on the house.

Harvey Ramer

Thanks for the referral guys! Pittsburg is a good hike from my location. Believe it or not, Pittsburg is close to the same driving distance as Manhattan.

@TheKeymaster
While you live to far away for me to do an install, I would be happy to design the system for you and help you through the project. I recently did just that for a house that sounds very similar to yours. The owner is a piano player with no previous plumbing experience. He Installed the entire system himself, and did a wonderful job, I might add!
If that is something that interests you, feel free to contact me.

Rich_49

Some of the best installs I've seen on my designs were undertaken by homeowners with a slight mechanical ability . I would talk with Harvey about this . Other jobs , I have interviewed local contractors for clients and made my recommendations on whom to use based on those discussions . None of my designs from Alabama to Rhode Island have been unsuccessful to date . Call Harvey

JUGHNE

A 1910 house would look correct with the CI rads in place. IMO
You probably don't have enough floor to heat a house that size and of that vintage.
It is comfortable now because of the placement of the CI.
As bones grower older, a CI rad feels pretty good.

bob eck

In your type house from 1910 keep the cast iron radiators. I would look at installing a condensing combi boiler like the Lochinvar Noble where it heats the house and gives you domestic hot water. Can put in larger BTU model Noble boiler for higher domestic hot water output and the contractor can adjust the BTU input lower on the heating side of this boiler to match the house BTU heating load. Them look at running 1/2" or 3/4" Pex tubing from a manifold direct to each radiator. This way you can zone the house easier. If running pex to each radiator I would use the Viega Fostapex pex tubing with a aluminum in it that works as the oxygen barrier and this tubing will not droop or grow as you run hot boiler water through it. As you insulate the home and tighten up you windows you might find the radiators are oversized for the rooms and this is a good thing for using with a condensing gas boiler. If this is true you will be able to run lower water temps from the boiler to the radiators and thus you will use less fuel. Be careful how small you make your zones you do not want the boiler to be turning on and off all the time. You might be able to zone the house by 1st floor, 2nd floor, 3rd floor and so on. If going with a condensing gas boiler make sure your heating contractor and the wholesaler stocks parts for these boilers not a good thing to be without heat and hot water for a few says waiting for parts to fix the boiler and make sure you have a professional heating contract servicing your boiler and heating system. Good luck.

flat_twin

I would make every effort to keep and enjoy those cast iron radiators.

http://www.columbiaheatingsupply.com/page_images/Sizing Cast Iron Radiator Heating Capacity Guide.pdf

This guide can help determine how much your rads are capable of.

TheKeymaster

Thanks everyone for the help and suggestions. It's a great start for me to start planning this project out.

Grallert

Sounds like a fun project. Iwould keep the radiators and do the floor or some combination of the two. Radiators by the entry for mittens and boots. maybe in a focal point nicely repainted.and where ever it determined the floor can't carry the heating load. Best of both worlds.
M

nicholas bonham-carter

How would you control the separate zones of floor and radiators?
Each circuit will need a different water temperature.--NBC

Grallert

I'd run the system with a water temp appropriate for the CI on a design day, and mix that same temp down for the floor. I think you could get away with one thermostat this way. Or install thermostatic valves on the cast on a constantly circulating loop on reset with WWSD and control the floor with a simple three way valve and a pump with a thermostat. That's how I did my kitchen.
M

TheKeymaster

That's one of the things I wasn't sure of before I came here. I know a couple people that just added 1 room of radiant floor(bathroom), but they didn't kick the temp down for the water I don't think so that room is ok heat wise with the door open but if you leave the door closed it gets too hot in there. Like sauna hot! I don't want to have to control room temps by leaving doors open or closed obviously. That's basically what got me asking question here.

I took a snip it out of a picture I took when walking the house. It's not the best pic of the radiators in the house, but maybe someone can tell me the style. I haven't looked to see if there was any etchings on the radiators yet to see if they said anything about them.

Grallert

The floor really needs to be controlled never hot to the touch. I think the surface temp should be around body temp but no more. That floor will often not reach that if the water temp is controlled by the out door temp and room temp.

Harvey Ramer

The floor should always be cooler than body temp by a minimum of ten degrees in most normal applications.

How to control the floor and the rads depends on the EDR of the current rads as compared to there respective loads and the potential output of the floor in the same space. It is easily done in multiple different ways. Some ways cost less than others, which is why it pays to do the math and find out what will work.

TheKeymaster

I was talking to an architect that I know. He said that his plumbing guy just drills a bunch of holes in the floor joists to run radiant floor heat back and forth. He said then they just run the water the same temp as it is in the radiators and don't use any mixing values. Suggested that the floor doesn't get too hot because the tubes are a few inches away from the floor. Also that it's heating the air space so they don't get cold spots where tubing isn't. I don't think they insulate anything either unless it's a floor that is touching the ground. Logic is that the heat is in between floors so it goes into the house either up or down. Have they just got lucky that this works the times they did it or is this a different kind of install? Or a different kind of system totally? I can't seem to find anything about doing it this way. The installs they have done this in are all in older homes. They don't do any new construction. Seems to me this way is just wasting money because you are heating the water so much hotter than radiant floors I've been looking at. He did say that his biggest complaint when they install the staple up is people say spots of the floor are warm and others are cold depending on where you stand. Says doing it the other way he never gets that complaint.

TheKeymaster

On a visit to the house I realized the 3rd floor doesn't have any radiators. There's a couple spots that may look like there was a radiator, but I'm not certain. The house had gas lights at one time and also (not sure why) but added gas heaters to a room or two. So there's a few lines of things I'm not sure what they go to.

We are leaning to keeping the radiators if they put out enough btu to make it comfortable after calculations. Adding radiant floor heat to all the bathrooms and possibly the master bedroom.

Third floor we aren't sure. The ceilings aren't as high as the rest of the house. The first 2 floors are solid masonry, but 3rd floor is frame. We will be spraying foam into the walls and ceiling on the 3rd floor. It doesn't have as many window either and they are normal size except one as opposed to the first and second floor which has monster windows. I'm thinking just radiant on the 3rd floor would cut it btu wise to heat the space. It's only pine floor up there since it was cheaper for maids area I think. We are taking all that floor up anyway to make it easier to run electric to the entire second floor so will have access.

Jamie Hall

Your architect's approach will work. Whether it works efficiently or not is another question entirely. In reality this isn't a radiant floor system, rather it's a system with hot water heat with the emitters being tubing rather than baseboards or radiators, and placed in an out of the way location.

A properly designed and installed radiant floor system will not have hot spots and cold spots (though it can have warmer spots where you want them, like a bathroom!) and will run on remarkably low temperature water -- hence remarkably high efficiency.

Since you are tearing up the third floor anyway, you could put a properly designed radiant floor system in when you reinstall the floor. Emphasis on properly designed. But make sure you do your heat loss calculations to be sure that the floor will have the needed capacity.

TheKeymaster

From reading this forum, I definitely won't be making any changes until I run all the numbers. Even if we just use the existing system for a year or more to see how it functions and what the gas bills are like. It might work great and bills are reasonable enough not to make major changes with up front cost.

I called the gas company last month and the budget amount in 2015, which is as far as they can go back, was 250 a month. For a house this size I can stomach that and it should get a lot better once we fix up some windows and insulate the 3rd floor and roof. It was much lower after that, but no one was living there as the lady passed away. My only concern is if the lady kept the house really cold because she was only using 2 rooms on the first floor and then had maybe an electric heater in those 2 rooms. In which case the gas could be much higher. On the other hand she and her family have old money I think, so maybe she didn't care what the gas bill was and kept the house set at 76 degrees because she was 94 years old and wanted it warm in there. I'm hoping for the later. That way keeping it at a regular temp the gas bill will drop to like 200 a month budget easy and once insulated upper floors maybe hit 150 which would be fine and not worth a change.

Ironman

TheKeymaster said:

I was talking to an architect that I know. He said that his plumbing guy just drills a bunch of holes in the floor joists to run radiant floor heat back and forth. He said then they just run the water the same temp as it is in the radiators and don't use any mixing values. Suggested that the floor doesn't get too hot because the tubes are a few inches away from the floor. Also that it's heating the air space so they don't get cold spots where tubing isn't. I don't think they insulate anything either unless it's a floor that is touching the ground. Logic is that the heat is in between floors so it goes into the house either up or down. Have they just got lucky that this works the times they did it or is this a different kind of install? Or a different kind of system totally? I can't seem to find anything about doing it this way. The installs they have done this in are all in older homes. They don't do any new construction. Seems to me this way is just wasting money because you are heating the water so much hotter than radiant floors I've been looking at. He did say that his biggest complaint when they install the staple up is people say spots of the floor are warm and others are cold depending on where you stand. Says doing it the other way he never gets that complaint.

Once again, I'll post my handy summary chart from the Va Tech study that shows the btu output of different types of radiant floor systems:




You'll notice that the method your architect is proposing gives 7 btus per square foot at 110* SWT which is the normal SWT that we design for with staple up. IDK what output you'll get with 160* SWT, but this seems like a bad idea to me.

PROPER design is the key to getting a radiant floor that works properly. Your architect admitted there's no design criteria for this method.

TheKeymaster

Thanks for the chart. I was just curious if his way was even a thing. He doesn't do much of this type of stuff and mostly specializes in high end kitchens. I'm guessing that the people that he does kitchen remodels for don't care what the gas bill is because they are loaded anyway. He's gotten lucky and had the rooms be a livable temperature doing it that way maybe.

JUGHNE

Many kitchens have minimal exterior wall exposures and often small window above sink that you don't sit near.
The refrigerator may heat the room and then throw in some cooking and DW.
His method may add heat but probably main benefit is keeping the floor barefoot warm. IMO

modconwannabe

As a homeowner of a 1910 brick rowhouse—which has very different heating conditdions than a freestanding home—who did a version of what you're asking, I would do my calculations and if it works out, have a nice ceremony for the rads and give them a nice new home. I love old home, love the look of old radiators, but man getting rid of the those big honking things completely changed how we were able to use our home, and underfloor heating is terrific--insanely efficient with a modcon boiler. The caveat is we put up an insulated wall over our brick/plaster exteriorer which is not a big deal for a 20' wide rowhouse, but isn't so easy for freestanding. An install like that is going to cost plenty though, 20-30k in my neighborhood for 3 floors and new boiler.

Boon

When I see the "hundred years from now..." quote my brain wants to fill in the last half with, "...and then rip it out and replace it with staple-up."

Steamhead

TheKeymaster said:

That's one of the things I wasn't sure of before I came here. I know a couple people that just added 1 room of radiant floor(bathroom), but they didn't kick the temp down for the water I don't think so that room is ok heat wise with the door open but if you leave the door closed it gets too hot in there. Like sauna hot! I don't want to have to control room temps by leaving doors open or closed obviously. That's basically what got me asking question here.

I took a snip it out of a picture I took when walking the house. It's not the best pic of the radiators in the house, but maybe someone can tell me the style. I haven't looked to see if there was any etchings on the radiators yet to see if they said anything about them.

Early type of American Rococo radiator?

TheKeymaster

Rococo is what I think I have it narrowed down to. I don't have the greatest pics of any of them. I'll be going there this week to meet an inspector, so I can look more closely. All the pics I have now are from an angle like this one so I can't see if it has the rods through them like the earlier Rococo or they are a later model. That and I need a better end shot to see the detailing better and see if I can match it with a Rococo.

Is it wise to try and see if the knobs work freely while I'm there? My concern would be I might cause a leak and no one would be there to see it. It could leak for a week if not a month before it might get noticed. Also should I mark the knobs so I can turn them back to exactly where they were in case it's set up to heat evenly. I wouldn't want to screw up someones years of tweaking them to perfection. Which would be great and lucky.

Jamie Hall

If it were mine, I'd leave the valves alone until I was on site to keep an eye on them... they'll work (they're pretty simple, after all) but it's quite likely that at least some of them might leak and need the packing tightened -- or repacking -- after they've been tweaked.

TheKeymaster

Just a couple other pictures I grabbed of what the house is running on now. I took some other pictures of the piping, but it seems typical to old houses I've seen. I was trying to figure out the age of the boiler. I called hydrotherm but their computer was down(funny as my internet was down at work when I called them). They are supposed to call me back, but we will see if that happens. There's a 1977 on the tag, but not sure if that's the date or something else.

Ironman

So, it's at least 40 years old and has sooted up judging by the appearance of the top.

New boiler time.

TheKeymaster

There was another question about radiators in a kitchen. That reminded me of a question I had but I didnt want to hijack someones thread.

The house in question has a pretty huge kitchen, so losing space in there isn't a big deal. It's the wall space that's a premium. What I was thinking is what if I just install cabinets in front of the radiators. I'd obviously leave a blank space where the radiator actually is. I just mean they'd start out from the wall far enough to clear the radiators. What I'd do is get a counter top made deeper. So instead of a 24" counter I'd end up with maybe a 40" counter. The extra space would be nice because you could keep things like toasters and stuff way back against the wall. They'd be easy to pull forward and use, but you wouldn't have a 10" piece of basically unusable counter where you keep all your appliances. You'd still have the 24"s if not more. The radiator would kind of be built into the cabinets.

I know I could just do the same thing and put the cabinets against the wall, but the radiator is in front of the window and that where I'd like to put the sink so that's why I thought extra deep counter.

I guess my question is would that affect the radiator performance drastically if it's set back in that far. I'd reflectix it all up, but it's still going to be dead air in there. Plus it would heat up my sink something fierce and everything in the adjacent cabinets which I just thought off. I'd be losing that foot and a half of dead space behind the rest of the cabinets, but I could use that space to insulate some of the solid masonry wall. It would only be a small portion of the rooms walls, but it's gotta gain a little on the heat loss.

TheKeymaster

Wasting a minute at work I drew it up really fast and ugly with just made up dimensions basically. It might make it more clear as to what I meant though.

Steamhead

Don't do it. Servicing or bleeding the rad would be very difficult, if not impossible.

We were working in a house once where a guy who thought he was an A/C contractor ran a duct right in front of a third-floor radiator. When we pointed that out to the owners, he got fired.