baseboard + Electric heating...

kayzee

Question: is it possible to run hot water baseboard heat with electric baseboard heat controlled by the same thermostat?

Setup: I purchased an updated house with hot-water baseboard heating from a combi-boiler --- the system itself works well, however it seems when walls were taken down some baseboards went with them. The basboards that are left, just arent enough to heat up the (now) large open areas. Upstairs (with the same footprint) however has no issues. i plan on adding a couple of electric baseboards as we have solar and should be a savings (our current fuel source is propane). House is located in the New York.

TAG

Sure ... you would need a relay capable of switching the electric.

I had a ski house that was all electric and had a series of 50amp relays controlling some of the baseboard. To make it simple the relay voltage would need to match the hot water heating system ... my guess 24v

pecmsg

What temperature water are you producing?

kayzee

pecmsg said:

What temperature water are you producing?

i have a navien unit baseboards is set for 185º im not sure what its returning at and never checked as i said the upstairs with the same foot print has no issues heating up and both circulators are the same output

Jamie Hall

As @TAG said, just a matter of adding a (or some) power relays to switch the electric baseboard. The coils will almost certainly be 24 volts, controlled by the thermostat. The contacts must be rated for the electric baseboard power -- at a guess, 240 volts 30 to 50 amps. An alternative woold be a line voltage thermostat just for the new baseboards. The electric baseboard should (will, if you are going by code) need its own breakers on your switchboard.

Now on the solar. Um... well... no. The solar output will look nice on your electric bill, but electric baseboard heat takes a lot of power -- unless you have a very big array and very little baseboard you won't be even close. Especially at night...

mattmia2

I'd do some math before assuming that your solar will offset the electric resistance heat. Electric resistance take a lot of power. A heat pump uses a lot as well but a lot less so that might be an option. You have to look at your production, your storage if you have it or the rate you sell to the utility vs buy it back compared to the cost of propane.

You might think about some panel radiators to replace the missing emitters. With their radiant heat and mass they might let you be comfortable with a bit less energy use.

Robert_25

Are you currently generating a large surplus of solar power?  If so, how much? 

Replacing your existing hot water baseboard with high output baseboard is another solution for the rooms that are under radiated.  

Jamie Hall

I think I've heard this song before, but reality check time for solar voltaic trying to heat a house.

First, power deamnd. A pretty reasonable ballpark figure for a house in mid Ameria climates - say New York -- will take, on a cold day, somewhere in the general vicinity of 25 BTUh per square foot to heat (two story would be more, but let's say a ranch for the moment.

Second, power available. The solar constant -- the power from the sun -- is, for general purposes, around 100 watts per square foot, or 340 BTUh per square foot. The efficiency of a solar panel is around 20%. So the power available from a solar PV collector is around 60 BTUh. So at first glance one might say wonderful! If I pave half the roof with solar panels I can heat my house. Not so fast. The figure varies, but the gneral rule of thumb in the northeast is that, on average, you will have 3 hours of usable insulation per day (desert areas it's more -- 12 hours for tracking panels; 6 for stationary panels) So in a day, assuming anything east of the Mississippi here (or the Pacific Northwest) I can get a total of about 200 BTU per square foot out of my solar array. On the other hand, the house is going to lose heat all day, so i will require around 600 BTU to heat for that same day.

And that's with 100% coverage of the building footprint plus the ability to store the excess from when the sun is shining to use when it's not.

More realistically for most houses, you would be working with a third of the footprint -- and no storage. The panels won't even power the heat loss when the sun is shining, never mind when it's not, and there's no surplus to store.

Mind you, I'm not opposed to solar PV panels. I just wish folks would do their sums before they suppose they can actually heat their house with them.

kayzee

Robert_25 said:

Are you currently generating a large surplus of solar power?  If so, how much? 

Replacing your existing hot water baseboard with high output baseboard is another solution for the rooms that are under radiated.  

what do you mean when you say a high output baseboard?

jumper

Easier to use separate thermostats. If electric is more expensive then higher set so that it kicks in only when hydronic cannot keep up. Or other way around during afternoons when PV suffices.

EdTheHeaterMan

Standard output baseboard.
High output baseboard.


Notice the difference in the dimensions of the Standard v. High Output. and look at the difference in actual BTUh per foot.

I hope this helps answer your query

kayzee

Decided to add more baseboards / and switch over a few to high output as well -- Thanks all for the feedback!!