Can't Get Baby's Room Warm

WDecaneas

My Wife and I live in a duplex.  Our bedroom and main bathroom are on the ground level (IE basement) and on one zone of heat.  We have cast iron radiators and use a hot water boiler.  There is one manifold for both bathroom and bedroom.



We recently completed renovations to add a small second bedroom on this floor for our new baby.  The room is 7*14ft.  Our contractor put in slant-fin baseboard heating to the room (with PEX piping) and connected it to the same single loop zone as the rest of the basement.

The thermostat for this floor is in the bedroom.  We are finding that the baby's bedroom stays ~8-10 degrees cooler then our bedroom.  Our contractor has agreed to help fix the problem but we are stuck on the appropriate solution.  Three options have been offered up.  I'd love some feedback on which one of these might be best or if there's another option we're not thinking of.

1) Move thermostat:  We've had one recommendation to move the thermostat out of our bedroom and into the baby's bedroom or in the small hallway outside of this room.  I'm concerned that while this might help the baby's bedroom get to a temperature closer to what is set on the thermostat, that it won't solve the heat disparity between the two rooms...and that if we get the baby's bedroom up to 68...my wife and I will be boiling in our bedroom. 

2) Remove slant-fin baseboard and put in Burnham (or other brand) of cast-iron baseboard.  One plumber has recommended doing this.  He's indicated that it won't be cheap, but that having all radiators the same material and heat type (cast-iron radiator) will help keep temperature more consistent room-to-room.  He's indicated that the problem we're having now has to do with the fact that the cast-iron radiators, once hot, don't need much energy to retain their temperature and that the furnace shuts down for long spells...during these shut downs, the baby's room gets cold as the slant-fin loses all heat once the furnace goes off.

3) Replace slant-fin with electric baseboard...or add electric baseboard.  This recommendation came from the electrical inspector.  He said why bother trying to get temperature consistencies in multiple rooms off of one zone...just put in electric baseboard.  I'm not opposed to this idea...but like the idea of 2 better if it would work.

Thanks for everyones help!

DanHolohan

Radiators in your bedroom

Are they cast iron? 

WillDecaneas

Dan

Hey Dan,



Sorry for slow response...I can't seem to login into my original account so had to create a new one.  Anyhow, I'm the person who made the initial post.  To answer your question, the radiators in the older part of the basement are all cast iron.  One room has classic large radiators...the other has burnham cast iron baseboard.  The newly created baby's bedroom does NOT have cast iron.  In this room they installed slant-fin baseboard.



-Will

Ironman

C.I. rads + baseboard

This combo is never a good idea on the same loop as you're proving first hand.



Electric BB may solve the problem and be cheaper up front, but you'll pay much more to operate it, especially if you have natural gas. These BB also get much hotter at the element which may be a concern with small children.



C.I. BB may help, but may not be the only issue in this equation. If you have large pipes feeding the C.I. Rads and 3/4" pex feeding the baby's room, there may also be a flow issue. Water takes the path of least resistance and it will naturally seek to go through the larger pipes.



The best solution may be to install a properly sized cast iron rad with the piping sized for the same pressure drop (feet of head) as the rest of the system piping.



Some pics of the boiler, piping and rads would be helpful.

DanHolohan

Thanks, Will.

Cast-iron takes nine times longer than copper to come up to the same temperature. It cools at the same slow rate. Cast-iron baseboard and copper give off basically the same amount of Btus per linear foot, but the timing is the problem since they share the same thermostat. That's why the baby's room is too cool.



So options:



You could put the baby's room on its own zone. That may be a piping challenge.



You could have cast-iron baseboard installed to replace the copper, but that, as you know, isn't cheap.



You can get an electric space heater for the baby's room to make up the difference on the days when you need it.

Bob Gagnon plumbing and heating

Get A Price

To separate the piping and have a separate zone for the child's room. This may be cheaper than getting CI baseboard throughout, but it may not, get a price for both. A separate zone would be best because you could keep the two zones as warm, or cool, as you like. A lot of adults like to sleep in a much cooler room than they would have their baby sleep in, separate zones would allow this. Most important, when they remodeled they didn't make a small room out of the boiler room, did they? This is a common problem; if air for combustion is not allowed into the boiler room, carbon monoxide deaths could occur. Make sure you have multiple carbon monoxide detectors, and have your plumber take a look at the boiler room when he is giving you a price on the CI baseboard/ separate zone installation.



Thanks, Bob Gagnon

RobG

C.I. radiator

I would go with Ironmans solution. A cast iron radiator, sized to match the heat loss of the other rooms will prevent the boiler from short cycling as it will if it is on its own zone. You already have the existing piping off the same loop as the other bedrooms. Used cast iron rads are not too hard to find, just make sure that is is the right size.



JMHO,

Rob

remodel

CI and SF

Maybe....

1) Would switching the slant fin with the CI help?  So the CI is at the end of the loop and the SF in the middle and maybe oversize the CI in the baby's room, don't know if this aesthetically pleasing.

2) If you have a multi speed pump turn up the speed and see what happens, like the guys are saying might be a flow/air issue.  I had a problem like this on my system and turning up the pump speed actually helped.  Just make sure your velocity is within the recommendations.     

EricPeterson

TRVs

If you have TRVs (Thermostatic Radiator Valves) installed on the cast iron radiators, you can move the thermostat and have all rooms comfortable. Or just put a TRV on the bedroom radiator, since few would complain about a bathroom being too warm.



Simply replacing slant fin with Burnham might help some, but I doubt that 9" baseboard will match the heat output of upright cast iron radiators.



Another factor is how well insulated are the different rooms (heat loss).



Eric Peterson