Radiator sizing in gut renovated apartment.

info43

Hi All,

We recently gut renovated an apartment in 6 family building . The tenant called about the temperature in her apartment and it is a good 15 degrees colder than the apartments below and to the side of her.

The contractor replaced the standard radiators with baseboard type. They are getting hot but the EDR of all of the baseboards in her apartment total to 37.5 while the EDR in the surrounding apartments are 81.

Link to baseboard

I will have the plumber put back standard radiators but should I put back 81 EDR or 60 EDR as per the slant-fin app?

This is a one-pipe steam system.

Thanks for your time.

Jamie Hall

I'd put back the 81, and then use thermostatic vents to control the heat.

info43

Thank you @Jamie Hall

EBEBRATT-Ed

I agree with @Jamie Hall . Your going to put back in what you took out otherwise you will be out of balance with the other apartments.


I am assuming all 6 apartments are heated by one boiler

info43

thanks @EBEBRATT-Ed yes all 6 apartments are heated by one boiler.

JUGHNE

Wouldn't restoring the original EDR but then cutting down usage with TRV's have the same effect on unbalancing.
This apartment should have better R-value..... or not??

Fred

I would think with only 81 EDR total, using adjustable venting and keeping them slow would be all that's necessary.

info43

@JUGHNE It does. Double pane windows replaced the single pane, added foam board on top of the plaster on brick and replaced the insulation between the ceiling and roof.

@Fred Now all 3 apartments in the rear of the building had gut renovation in the last 20 years. While no one has moved out of the front in the 25 years I owned the building (rent stabilization). I am thinking to add TRVs to all of the rear radiators.

My boiler will need changing soon. I'm toying with the idea of 2 small boilers since both sets of apartments have such different heat loss and they are on separate loops already.

MilanD

Fyi, not sure if you already had this looked at, but be careful when insulating brick buildings from the inside. Depending on what kind of brick/mortar combination is used, old brick buildings may need to be insulated from the outside... Old bricks need heat from the inside to control moisture and freez/thaw cycle and can fail prematurely if insulation is applied on the inside. I live in 1912 soft brick house and after looking into this, the only recommendation was outside rigid insulation with furring strips and either siding or stucco over that... Fwiw.

Kahooli

Exterior insulation over beautiful brick... Gross!

MilanD

> @Kahooli said:
> Exterior insulation over beautiful brick... Gross!

Yep. Agree. The only way to do it properly while maintaining structural integrity. It is what it is.

http://www.greenbuildingadvisor.com/blogs/dept/musings/insulating-old-brick-buildings

Fred

@info43 , be careful about adding TRV's to too many radiators. If enough of them are closed, at the same time, that will actually over-size the boiler, during those heat cycles and cause short cycling. With only 81 EDR in each unit, adjustable radiator vents, like the Vent-Rite #1 or the Hoffman #1A should be more than enough to control the comfort level in each unit.
Also, two boilers for a six unit building, with 81 EDR in each unit (total of 243 EDR per boiler) might be smaller than any boiler you can get, compounding a short cycle potential. One boiler around 460 to 480 EDR is an average size residential boiler and probably makes the most sense.

info43

Wow @MilanD I never heard of that. Thanks for the info.

Funny thing @Fred, I have numerus issues with my system right now and thanks to the people on this site, I am working on the one at a time. I got a couple quotes to replace my boiler, neither person was planning to size the boiler, they were going to replace WM EG-75 with the same size and bother the were both going to keep my near boiler piping even though it has issues.

Fred

@info43 , clearly none of those contractors are ones you want touching your system! Find someone from the "Find a Contractor" tab on this site. An EG-75 is way too much boiler for 480 Connected EDR.