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efficiency duel: elec. baseboards vs. elec. boiler

ALH_4
ALH_4 Member Posts: 1,790
But you can zone every room individually with a hydronic system also and use whatever fuel you want. I think committing to electricity is a bad idea at this point.

-Andrew

Comments



  • ok, here's the scene: a local non-profit organization just purchased a new building and are gutting and renovating it to suit their needs. I saw they were planning on installing electric baseboards for heat so I offered to install a hydronic heating system at just the cost of materials with no markup: panel rads with TRV's and electric boiler with outdoor reset. (they have no gas in the building and don't want it either)

    so, they like the idea but my system is still 3 times what they were planning on spending for baseboards. they don't doubt my claim that the hydronic system will be a more efficint use of their elctricity, but they want an actual percentage savings figure they can give to the money handlers.

    I wanted to throw out a number of "at least 15%, maybe more" but I really don't know how to quantify this comparison, any thoughts/experience with this?
  • Brad White_65
    Brad White_65 Member Posts: 3
    A kW is a kW...

    Noble intent, Zac- cannot fault you there! But the crux of it is, all electric resistance heat is about 100% efficient and costs whatever it costs.

    Sure, the "oil filled" radiators and the like cycle less compared to straight resistance baseboard as one example. But you wait for the warm-up and it "coasts" on the cool-down. Same as your hydronic system will. All you are doing is adding mass.

    Speaking of which:

    You can better leverage their electrical bill with thermal storage to take advantage of off-hour electric rates if any. Better still, a ground-source heat pump as a low temperature water heating source at any time of the day. COP's should make it worthwhile or at least give you a comparison point compared to resistance. As it stands, resistance for resistance, you do not have a payback basis.

    Here is the key to what I like about your idea: I don't know what your local electric rates are nor how stable they are. But let's assume the rates will be as volatile eventually as every other source of energy. The big service you will be providing is to situate them for a "fuel to be named later" (WSHP, Ground source heat pump, oil and if they come around to it, gas with a condensing boiler) plugged into the distribution you provide. Only the electric boiler is at risk of waste and that can be a standby for the eventual ultimate solution.

    If your electric rates are anything like ours here in MA, that alone will do it's part to keeping that non-profit from ever making one. A lot of businesses here will be "non-profit" soon enough :(


    Best,

    Brad


  • thanks for your reply.

    a couple more points: our electrical rates here are constant (no peak times) and some of the lowest in the continent.

    when i look at the whole system: constant circulation with outdoor reset(instead of baseboards 100% on or off cycles) TRV's on all rads, and whole building programmed setback ability (as opposed to individual thermostats that may or may not get turned down at night) It just looks like the savings will be quite significant, I might just have to throw out a number based on gut feeling and see what happens!

    and I did advise them of the flexibility of converting fuels in the future with hydronic (they are in a good solar spot!)

    any more thoughts?
  • jim lockard
    jim lockard Member Posts: 1,059
    Insulate

    Are you not going to cool the building? What about heat pumps or water coils? IMHO the most effective use of energy money is to insulate as best and completly as you can. Best Wishes J.Lockard


  • we have quite a temperate climate here, (AC? open a window!) at the moment heat pumps are out, the budget is very tight, i'm just trying to get them a decent radiant system for the lowest possible cost. the building will be R20 walls and R40 ceilings.

    on that note, I agree on your insulation point, I don't understand why people don't go above and beyond what's required by code with insulation. I just read an article about low energy houses in Germany that have no heating system, the homes are so well insulated just internal gains (appliances, lights, etc) heat the building! I guess people just enjoy spending money here...
  • Brad White_9
    Brad White_9 Member Posts: 2,440
    Low Electric Rates and Savings

    With favorable electric rates your payback basis is even less (save what percent of what small number?)

    I think, Zac, that your approach should be one of comfort, not economy at least at first. The notion of adding solar has incredible "green" appeal if nothing else. Preserving future options as I said above, still has broad appeal.

    I would not (being a design professional) 'throw out a number based on gut feeling and see what happens' for the princpal reason that they will make financial decisions based on that. You could be held accountable when their borrowing costs exceed the savings.

    Fine tune the hydronics all you like, you are still metering in kWH at a rate equal to BTU's out. No changing that equation unless you use a heat pump.

    Comfort and future are your salable commodities here, not efficiency if you are talking straight resistance.

    My $0.02

    Brad
  • nick_7
    nick_7 Member Posts: 15


    I think it has to be that electric baseboard is inherently more efficient than electric hydronic. I think it is a law of physics that you will lose some enery heating water electrically and then heating a house with that water. Also, it takes electricity to circulate the water. Add the extra expense and operating noise of a hydronic system and I thik it is clear that if all you have for an energy source is electricity, electric baseboard or embedded cables or heat mats would win. The real advantage of a hydronic system I think would be that you could change your energy source in the future.
  • Brad White_9
    Brad White_9 Member Posts: 2,440
    Some good points

    depending on where the water is heated (losses to a basement mechanical space versus direct to the space) and the pumping costs, of course. That is the best point.

    But I would submit that hydronic heating, properly sized, would be quieter than creaking electrical elements. Heat mat? Not an issue. Radiant over convective rules...

    Also electric baseboard precludes you from running electrical outlets above them.
  • ALH_4
    ALH_4 Member Posts: 1,790
    Or

    if you decide to add an alternative energy source in the future, hydronic wins. There is a lot more flexibility as fuel prices change.

    -Andrew
  • JJ_4
    JJ_4 Member Posts: 146
    Some suggestions

    If you go with electric baseboard, then at least use "hydronic" electric. There are several manufacturer's some with glycol (Qmark HBB) and some with silicon (Hydrosil)in a 1/2" sealed tube that surrounds the heating element. Seems like there would be some residual from the unit when the element is off, at least more than with a bare element. Get the 240V units...same Watts at half of the current used. 1500W/240V = 6.25A vs. 1500W/120V = 12.5A.

    Also, use a "controller" type thermostat. See the Aube Technologies TH106 (this is the same one that Hydrosil sells):

    http://www.aubetech.com/products/produitsDetails.php?noProduit=4&noLangue=2

    Unlike a typical stat which is on-off, either 0 or 100% current (amperage), this acts as a controller in that it varies the current to only what is calculated to reach setpoint.

    I use this "system" and rarely have my baseboard pulling any more than 25%...thats 375 Watts on a 6' unit that would use 1500 Watts with an on-off stat. Typically, I am within 1/2 degree of setpoint. This is in a new addition with R-38 ceiling (12' high)and R-19 walls.

  • Dave Belisle
    Dave Belisle Member Posts: 68


    One advantage to electric baseboard is you can control each room individually. So if rooms are not being used the temperature can be turned down. The other plus is the installed price. Nothing can touch it.
    When I got married 35 years ago my home was total electric. It cost me $35.00 a month for electricity.

    Well we all know that has changed , I have made a good living pulling out electric baseboard and installing hydronic.

    One big plus for hydronic is that no electrical outlets can be installed over the electric baseboard per the electrical code.
    but there are no restrictions on hydronic. Electric baseboard gets VERY HOT !!

    Truth is , Electric baseboard is going to be the cheapest to install and you get room by room control. ( WOW !!I can't believe as a Hydronic guy I just said that !!!! )


    Dave

    BP&H
  • yes but..

    at the same token radiant panels heat the occupants directly through radiation where as elec. baseboard (like forced air) heats the air which then heats the occupants which ends up ultimately requiring a higher temp to adequately heat the space.

    I think I will be honest with them though and say I really don't know how much they would save (if any) by going hydronic, i'll instead expound the comfort benefits and future expandability options.
This discussion has been closed.