Hot Water Baseboard with Double Element

BrooklynMike

Recently purchased this house which had a kitchen renovation that included a family room addition done several years ago. In the kitchen part, we found a 10 ft section of baseboard radiation with two fin tube elements installed one on top of the other. I guess this was done to increase the heat output since wall space for baseboard radiation is limited in the kitchen. Has anyone seen this done before? Is it effective in increasing the heat output or is the airflow through the baseboard decreased. I am thinking about replacing it with normal high output baseboard with the jumbo fins.

bburd

That is a perfectly valid solution to the problem of limited space. Manufacturers publish rating charts that give the heat output for that setup, which is less than the same length of element as a single course because the first element heats the air before it passes through the second, where it picks up less heat due to the smaller temperature difference between air and radiator.

What problem are you trying to solve? Is the room too cold? The same length of single tier high output baseboard would probably provide less heat than what you have.

EBEBRATT-Ed

Agree

BrooklynMike

Thank you both for "okaying"this configuration. The problem I am trying to solve is that this kitchen/family room is 3-4 degrees cooler than the rest of the main floor of this 1955 home. The house uses monoflo tees to supply the baseboard radiators. A 1 X 3/4 monoflo tee supplies 33' of baseboard radiation plus 45' of 3/4 supply/return piping . 10' of the 33' baseboard is the double element I described. Thinking of options: add another monoflo tee to increase GPM, adding baseboard on some exterior walls to add BTUs to the room, putting this room on its own zone and thermostat. I now know to leave the 10' double element section as is. Thanks again

Intplm.

@BrooklynMike
You can get a heat loss calculation done for that space. Kitchens can often suffer from lack of baseboard because of the use of cabinet space.
The doubled up fin tube could be common fin tube baseboard. High capacity/high intensity baseboard might also be an option that could help with heating that space.
A heat loss calculation is a good way to go if you feel you need more heat. "High cap" baseboard doubled in that area might help.

bburd

So the kitchen/family room addition is not a separate zone with its own thermostat. What kind of radiators do you have on the rest of the zone? Copper fin tube or cast iron?

BrooklynMike

Bburb & Intplm, The kitchen/family room is not a separate zone. It is supplied by a 1 X 3/4 monoflo on the return side. Supply side is a standard 1 X 3/4 tee. This area has modern slant fin copper/aluminum baseboard. The rest of the house has a brand unknown 1/2" baseboard with (I think?) heavy gauge steel fins. The heat loss calculation is not straight forward because the family room part was a open breezeway to the detached garage that was enclosed years ago. The room is on a slab with a floor on joists( I think), a vaulted ceiling with skylights , 3 exterior walls and large window and door glass and a box bay cantilevered over the foundation. Insulation unknown. To add to the details, I recently had a central HVAC system with a heat pump installed and an Ecobee 3 lite smart thermostat. I am using an Ecobee remote sensor in this room as the primary sensor for the thermostat and using the backup hot water heat now during the cold months. ai am keeping the room at 70 and still feel chill sometimes by the windows. One wall of windows has no baseboard on it. Would like add baseboard under the window but have no access from below for piping. Thanks again.

bburd

As a general rule of thumb, additions are most comfortable when they are heated as a separate zone. Generally the construction is quite different from that in older buildings, so the heating load profile is different as well.

This goes double for when the radiation is not identical to that in the existing building.

You might be able to add baseboard under those windows by tapping into existing piping above the floor, which might involve a short run of surface mounted pipe or concealing the pipe in an additional length of baseboard enclosure or by boxing it in.

Remember that you can feed a run of baseboard from one end and run the return line over the baseboard element back to the same end. The factory enclosures are designed for this.

BrooklynMike

Bburd,
You are totally correct. 1) The baseboard in the room in question does have the return line above the element and share a common floor penetration. 2) I have a way to feed a new piece of baseboard but it's kinda hokey because I would have to pipe from the baseboard into a small chase in a mud room, then behind and under a small set of wood stairs, then into the a chase in the garage and then back into the existing baseboard using PEX to make in easier then sweating copper. In effect, i am running PEX below the level of a doorway to the garage but it would work. Thanks

EdTheHeaterMan

BrooklynMike said:

...The heat loss calculation is not straightforward because the family room part was a open breezeway to the detached garage that was enclosed years ago. The room is on a slab with a floor on joists( I think), a vaulted ceiling with skylights , 3 exterior walls and large window and door glass and a box bay cantilevered over the foundation. Insulation unknown...

There is something that stands out here. The room temperature may already be the same temperature or it may be a few degrees cooler. But the fact that there is lots of glass reminds me of one of @DanHolohan's parables about the supermarket frozen food aisle. The gist of the story is that if you were to take a thermometer into a supermarket and walk down the bread aisle, or the cereal aisle, or the canned goods aisle, you might read the temperature to be 70° and you would feel comfortable.

In that same supermarket, using the same thermometer you would walk down the frozen food aisle and the temperature would also be 70°F. Then why do you feel cold in that aisle? That is because the frozen food is colder and your body’s radiant heat is working overtime radiating your heat to those cold packages of frozen pizza, hamburger, and ice cream. The air temperature is the same, your body just feels different. If you were outside and it was 40°F but it feels like 30°F, we would call it wind chill. In your home we call it draft. But what's really happening is those cold windows are causing your body to radiate heat to the cold outdoors. If you added insulated curtains, you would feel much warmer.

You might be better off if you could put that room on a separate hydronic zone with home runs back to the boiler and a separate circulator pump operated by a separate thermostat.
If you are going to the expense of draining the system down to add a second MonoFlo® tee, why not add some PEX piping to that problem room. And operate it as a separate zone. Then you can be sure that you have the right amount of heat regardless of the rest of the house.

If you go that route then be sure to remove the restriction tee from the system when you disconnect the radiator. Don't just cap it off.

BrooklynMike

EdThe Heater Man,
Your are correct . We probably feel the chill even though the room is at 70. Conversely, when the sun is out on a clear day, the room feels very comfortable. I plan on the doing the plumbing to put this room on a separate zone and would remove the monoflo tee or bypass it as you suggested. And would want to try to add baseboard to an exterior wall with a double window to reduce the chill factor. Thanks.

Long Beach Ed

We've often worked on kitchen remodels that don't have wall space for the correct amount of radiation. Sometimes a below-cabinet kickspace hydronic heater with an electric blower provides a huge output in small spaces. The blower is wired to a strap-on aquastat that turns it on when the heating pipe reaches a set temperature.

Check out the Beacon-Morris line. High output for the space.