regular vs hydronic electric baseboards.

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gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
191114-2008 EST

Air temperature is not the whole story.

If a human has a source of radiant energy impinging on their body, then that human can feel a given warmth level at a lower air temperature than, if just warmed by ambient air and convection heat transfer. By using radiant energy to heat humans the heating BTUs can be reduced for a given comfort level. Not heating up walls, and air as much, and thus less heat loss from the structure.

The radiant energy can come from anything heated. Thus, an electric resistance can be a radiant source (IR bulbs, a stove coil, a heater with no fan, a plain incandescent bulb).

An electric space heater with a fan is designed to heat the air, a bathroom heater with no fan is designed to warm you by radiant energy.

My gas furnace is strictly an on-off servo to control air temperature. Cycling about 6 times per hour in the first plots. My air temperature at the thermostat stays within about 1/2 deg F. See the last plot at http://www.beta-a2.com/wire-1.html . The last plots, P1 and P2, at http://www.beta-a2.com/wire-1_photo.html show a furnace cycle on a different day. Here cycle time is about 3 per hour. Presently I keep the blower on continuously. Was not the case when the above plots were made.

I could keep the home air temperature lower if I had radiant floor heating, and probably feel more comfortable.

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GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
191114-2008 EST

Air temperature is not the whole story.
...
...
'...

I could keep the home air temperature lower if I had radiant floor heating, and probably feel more comfortable.

But you would give up the opportunity to set back the thermostat at night without a very long cooling and reheating lag time. In addition to the potential energy savings, some people are simply more comfortable sleeping in a colder environment.
 

sameguy

Senior Member
Location
New York
Occupation
Master Elec./JW retired
As my dad would say "put more clothes on!",
my house in Central NY we run ceiling fans 24/7 and my programable tstat is on manual, gas forced air.
I could see #1 as true to a small part the rest bs.
You would need to figure the cost of bringing both masses to x temp then cost of maintaining x temp, then inject the upfront cost into the equation; with only a small square footage the electrical cost wouldn't be that much different. The feel of the air in a closed area would be better with the filled units.
 

sameguy

Senior Member
Location
New York
Occupation
Master Elec./JW retired
I think i'll stick it out w/ wood stove......~RJ~


Wood,
heats you when you cut it
heats you when you split it
heats you when you stack it
heats you when you move it to burn
heats you when you burn it
all controlled by opening and closing the doors and windows to the outside ;)
Thats a-lot-a heating from wood!
 

drcampbell

Senior Member
Location
The Motor City, Michigan USA
Occupation
Registered Professional Engineer
1. Hydronic baseboard heaters maintain balanced room comfort
2. Hydronic baseboard heaters increase energy efficiency
3. Hydronic baseboard heaters are safer for children and/or pets
4. Hydronic baseboard heaters are better for allergy sufferers
1: They might be quieter, but maintaining a constant temperature is determined more by the thermostat(s) than by the heaters.
2: Total bullshit. Electric resistance heaters are 100% efficient. All of them. No more, no less.
3: Do the other kinds pose any hazard? The heating element might operate at a lower temperature but is the cabinet temperature any different?
4: The lack of scorched-dust smell might be less annoying but the humidity angle is total bullshit. The humidity in the room is determined by the outdoor humidity, the ventilation rate and the amount of humidity added indoors, not by what kind of heater is in use.
There is some truth behind this. Houses with electric resistance heat tend to be better sealed and insulated because E.R. heat is much more expensive to run than gas heat or heat pumps. The reduced ventilation rate results in a higher indoor humidity if no active humidification takes place. Install a humidifier and it's all moot.
 

PaulMmn

Senior Member
Location
Union, KY, USA
Occupation
EIT - Engineer in Training, Lafayette College
I have 3 of these along the walls of my living room. They're about 4 or 5 feet long and about 7-8" tall. The stick out from the wall about 2-3".

If you remove the front panel (held on with some springy prongs) there's a heating unit that is stuck into a loop of pipe with fins. The heating element heats the liquid in the pipe, which circulates and heats up the whole length.

They are a nice, even (dry) heat. There'd only be moisture if you placed a skinny bowl of water on top and let the heat evaporate the water.

The temperature is even along the length of the unit. You can touch the top of the radiator and not get burned.

I'd agree that #1 is true-- it's an even heat.

#2 is anyone's guess. Sounds like the marketing department at work.

#3 I'd agree- you're not likely to get burned touching the radiator. It may be uncomfortable to leave your body part touching it, but I don't think you'd get a serious burn.

#4 I think this is more marketing. The only fluid involved is sealed inside copper pipes with fins all over them that live inside the housing.

One use I've found is to help prevent fires-- any of those candles-in-a-jar that smell nice when burned work just fine sitting on top of the radiator. No flame required. Pumpkin spice, Christmas Tree, and Apple Pie are my favorites.

The ones I'm describing are permanently mounted, hard-wired (240 volt, 240 volt thermostat).
 

PaulMmn

Senior Member
Location
Union, KY, USA
Occupation
EIT - Engineer in Training, Lafayette College
Ignorant Brit strikes again.
What is a hydronic baseboard???

It's an electric heater, about 4-5' long, about 8" tall, about 2-3" deep. It looks like a section of any other baseboard radiator, but is all electric, no moving parts, and not plumbed into a furnace or anything.

Mine are fastened to the wall and hard-wired into the electrical system.

Inside the unit, heat is provided by a U-shaped copper tube with fins. At the open end of the U, both ends meet in a heater element. The tube is filled with oil or other liquid. Power goes on, the oil heats up, and convection moves the oil through the tube. The whole tube gets hot and heats the room.

Search for >hydronic baseboard heater<
 

sameguy

Senior Member
Location
New York
Occupation
Master Elec./JW retired
Ignorant Brit strikes again.
What is a hydronic baseboard???


Baseboard area where floor meets wall.
hydronic tube filled with liquid.
like the portable liquid filled heaters, the ones in question are a sealed, no pump, no boiler, just a fin tube in a metal box screwed to the wall about 6" above the floor with 240v controlled by a thermostat .
 

junkhound

Senior Member
Location
Renton, WA
Occupation
EE, power electronics specialty
I hear ya, I tried and the GC tried too. They seem to just be focused on initial cost not long term. Splits work down to -10 or so, so they work great even here in central NY.

Seattle still has low rates (but not PSE) so low initial cost may make sense if only 1 or 2ea 500 W units are being installed in a bathroom or such as supplemental heat. Anything much more than that the mini-splits should even be lower initial cost :huh:

Ya mention a GC - does the WA state energy code even allow resistance baseboard heat of any type in new construction?
 

Besoeker3

Senior Member
Location
UK
Occupation
Retired Electrical Engineer
Appreciate the answers, thank you. I know what a baseboard is. We call it a skirting board here. Ir was the "hydronic" part I didn't get.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
191115-1549 EST

More comments relative to radiant heat vs heated air.

Radiant heat does not require a large mass. Consider a 150 W IR incandescent reflector flood bulb. If this bulb was made with a vacuum, then almost all electrical input energy would come out as radiation (IR, visible, and UV). When this radiation hits something, then that something absorbs some of that energy, and warms. From the IR bulb there would be some conducted loss, but small. But even the way bulbs are made there is not much conducted loss. Also note that response time is only a few cycles.

A floor based IR system does not have to heat a lot of mass, but in many applications it does (pipes in poured concrete). With mass you have longer response times, may not matter. The power input control algorithm would probably include outside temperature and windspeed as well as internal temperature.

For a well insulated home a setback temperature control may have no advantage. My home has moderate insulation, but not good by today's standards. With a 30 F outside temperature and an initial temperature of 74 F inside it takes about 6 hours to drop to 70 F with furnace off. With today's standards it might take 12 hours or more.

If I do a setback, then it takes a long time to get back to 74 F after the setback is returned to its normal value.

If you do heating by forced air, then you warm the air to warm humans as well as everything else. This makes outside walls hotter than when using radiant heat, and thus greater heat loss for a given comfort level.

If the device of post #1 is really a radiator, then it is useful, but also a plain open resistor can be a radiator. What may be more important is the surface area of the radiator. For the same radiant energy (power) level the large surface area device will be a lower temperature, and thus produce less air circulation and air heating.

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