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Our home was build in 2001 and currently has a oil furnace that is at the end of its life. We are looking for a more efficient heating option and stumbled across an electric radiant heating product called STEP HEAT that can be installed between the floor joists (we have access) so we wouldn't need to remove the existing floors. Would it be possible to heat the entire home with a product like this or would it be considered secondary/supplemental heating?

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    Where are you located, and how well insulated is your home? How big is the existing oil furnace?
    – Khrrck
    Mar 18, 2022 at 17:30
  • Use the sun... Solar water heating works and the running costs much lower than heat pumps. You don't say where you are but swh pays for itself in under 10 years in some countries.
    – Solar Mike
    Mar 18, 2022 at 19:25
  • "Between the joists" means it radiates through the subfloor and all, arbitrary, floor coverings? By "entire home" do you preclude installing carpet anywhere, or are you asking if this product works through carpet? Are you asking if floor heat is generally more efficient than (probably, you don't say) steam or hot water radiators? Or are you saying that this particular brand is heated by some source that is more efficient than oil?
    – jay613
    Mar 18, 2022 at 20:15
  • Do you see value in having a heating solution that will run when there's a fuel, even if the power is off? Think Texas and the big freeze last year. Pure dollar cost isn't the only consideration.
    – Criggie
    Mar 19, 2022 at 10:11
  • The one advantage of electric is the initial installation is usually much cheaper. Of course that doesn't matter because that advantage is completely negated by much higher heating costs. Electric radiant is like "what if all the additional expenses of electric heating but also hideously expensive installation cost, too!!!" . It's hard to think of a worse option.
    – eps
    Mar 20, 2022 at 1:11

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You can. But don't.

Resistance electric heating, no matter what the fancy name, is really a giant toaster. Toasters are wonderful things - for making toast. But you use a toaster for a few minutes a day and that's it. So it doesn't use much power. In fact, because a toaster concentrates most of the energy onto bread/waffles/etc. instead of heating up a large oven, it is actually very efficient.

But using a toaster to heat your house is not very efficient. Generally speaking, due to conversion efficiencies, peak demand issues and other factors, resistance heat is generally the least efficient way to heat an entire house. It works well as supplemental heat - little 1500W space heaters under desks and in corners of cold rooms, etc. though even that can have some problems.

In most places, the better solutions are:

  • Oil or (even better) natural gas heat. This uses fossil fuels, but so does a large portion of utility electricity generation (especially peak demand). But since it is at point-of-use, the conversion loss from fuel to heat is typically a lot lower, especially with modern furnaces, than fuel to heat to steam to electricity to heat which you use with electric resistance heat.

  • Heat pumps. A heat pump works as an air conditioner in the summer and a heater (using the same mechanism in reverse) in the winter. Within certain constraints, a heat pump can produce a lot more useful heat than the same electricity would produce via resistance heating.

If you already have air conditioning then you have ductwork in place and a heat pump is worth considering. If you don't have (and don't need) air conditioning, then I would recommend a replacement oil furnace unless you have utility natural gas available, in which case a natural gas furnace would be a bit of an improvement (generally cleaner burning, no need for oil deliveries).

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    @gidds It's the latter (sort of). Rather than converting electricity to heat, heat pumps use electricity to move heat. It turns out that moving heat can be many times more efficient than just creating it directly.
    – anjama
    Mar 19, 2022 at 13:25
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    @gidds A) Because in order to get the electricity to your house the electricity has to be created. The most common way to produce the electricity is [generate heat] --> [turn water into steam] --> [use the steam to turn a turbine] --> [use the rotating turbine to produce electricity] (which you then use as [electricity] --> [generate heat]). Each "-->" represents changing the form of the energy. Each transformation of the energy tends to be inefficient (some quite inefficient, some not too bad), but those inefficiencies multiply for each time you do a transformation.
    – Makyen
    Mar 19, 2022 at 14:42
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    Thus, it's substantially better to just generate the heat and use the heat, rather than transform the energy multiple times. B) As already mentioned, if you have to use electricity, heat pumps can be, and most modern ones are, substantially more efficient than just directly generating heat from the electricity (depending on the equipment and conditions). If they are sufficiently more efficient to make up for the inefficiency of the other energy transformations needed to get the energy depends on the equipment, situation, and how the electricity was generated.
    – Makyen
    Mar 19, 2022 at 14:43
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    @Makyen I think my confusion comes from interpreting ‘inefficient’ in thermodynamic terms, about the choice of individual heating system — while perhaps OP was referring (like you) to the bigger picture. Converting electricity to heat is the only electrical work that can be 100% efficient! But yes, if you consider the entirety of the energy flow, it can be very inefficient at heating a home relative to other methods.
    – gidds
    Mar 19, 2022 at 14:54
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    @gidds Well, actually, heat pumps can be a few to several times more than 100% efficient when comparing the amount of heat-energy which is deposited into the heated area vs the energy available from the electricity. So, looking at it from a thermodynamics POV, when just considering the energy efficiency of starting from electricity and the heat within the area being heated, heat pumps can be, and modern equipment is (under most common conditions), more efficient than just converting the electricity to heat using a restive heater at 100% efficiency.
    – Makyen
    Mar 19, 2022 at 15:13
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I had our oil-fired hot water baseboard (HWBB) heat removed when we had our major renovation done, went with all-electric (heat pump), and regret not leaving the hot water BB in. The heat pump works fine down to about 30 deg F. But the resistance auxiliary heating that starts to kicks in below that temperature is costly.

Prior to the change over, I had standard AC for summertime cooling (no heat pump) and the oil fired HWBB provided all the heat, in addition to heating the hot water. Since the changeover, my total energy cost (now just electricity) is lower than my combined oil + electric cost was prior to the change over by roughly $1,000/year. Even though I am ahead of the game cost-wise, I think I could have saved more overall had I used the HWBB as the aux heat (or even for 100% heating) on those days when the temperatures never rose above freezing.

I am in the mid-Atlantic region.

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  • I think it's worth noting that newer heat pumps are capable of handling lower ambient temps. 20F (and lower) is pretty common among the most efficient heat pumps on the market these days. The mid-Atlantic climate is pretty ideal for heat pumps.
    – pbristow
    Mar 20, 2022 at 18:24
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    @pbarrainis - Not taking issue with anything you said. But the winter time design temperature for this area is 21 deg F. That's what most HVAC contractors design for. But there have been a numbers of times when the daytime high never reached 21 F, and the nighttime low was in the single digits.
    – SteveSh
    Mar 20, 2022 at 18:28
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My retired parents had electric base board heat and liked it. A small ( 1000 sq.ft) new , well insulated house in a mild climate; northern Arkansas. Each room could be set at a different temperature. They did not complain about the cost but I do not know what it was. One drawback, adding central AC required installation of ductwork.

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  • Fair points! I'd imagine that heating needs in Arkansas are lower than, say Wisconsin. Since the OP didn't specify, this is as valid as any other option.
    – FreeMan
    Mar 18, 2022 at 20:23
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    That's why heat pumps come in "mini-split" form factor, which eliminates the ductopus and allows per-room control of both heat and air conditioning. The core unit is VFD, so it adjusts its output to suit the head units that are calling for heat/cool.
    – Harper - Reinstate Monica
    Mar 18, 2022 at 21:47
  • Yeah. But a lot of people, my SO included, find the wall or ceiling mounted indoor pieces unsightly. Sort of like a motel room.
    – SteveSh
    Mar 20, 2022 at 18:17
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Stepping away from oil is awesome for national security, as current events certainly show. (using less oil allows us to support our allies so they are not dependent on fascist governments, which seem to take over every nation whose economy depends on raw resources.)

Resistive electric heating? Are you sure?

However, this is "100% efficient" electric resistive heating. Which sounds great, except it's only 100%. The deciding factor in such an installation is the electric tariff or rate plan available to you.

The worst case scenario for any power system is 4 PM on a hot summer with everyone's automatic thermostat kicking their A/C on full to cool the house for people coming home, meanwhile factories are still going full-tilt and retail is open. This defines how many surge generators or "peakers" they have. However, a number of jurisdictions (Ontario; North Carolina) have a glut of nuclear or run-of-river hydro, which are expensive-to-build, cheap-to-run "use it or waste it" sources. They have the same crunch time as everyone else... but the rest of the time, they have too much base load. As such they have very favorable rates most of the time, and certainly anytime you'd want heat.

In such a plan, resistive electric heating makes sense - it'll just go over the spillway otherwise, or the nuclear plant will have to throttle down (changes increase maintenance; that's why Fukushima was trying to slow the cooling of unit 1, which was the first domino).

Heat pumps are the better plan

Without question in moderate climates. And, as a bonus, heat pumps provide air conditioning inherently. In fact the only difference between a heat pump and A/C is deleting the reversing valve so it can only go 1 direction.

Because heat pumps are merely moving heat, and not creating heat, they are highly efficient - vastly over 100%. That is, a unit with a COP of 3 can "pump in" 3 watts of heat for every watt of energy it uses. I.E. it is 300% efficient.

COP is a standard unit designed for comparison, but actual performance will vary with temperature.

When it comes to air conditioning, units are rated differently - in SEER, which is BTUs per watt. But 1 watt is 3.41 BTUs, so you can divide SEER by 3.41 to get "air conditioning efficiency". 13 SEER is the bare minimum legal to sell in the US (so 381% efficient), and I've heard of SEER as high as 39, or 1140% efficient -- wow!

Even in very cold climates, there are two solutions.

  • The latest heat pumps are really good at going low-temperature. Just the same, you keep (relatively cheap) electric toaster heating as a backup.
  • The heat pump can interchange heat with a ground source. Reasonably underground, temperatures are a fairly constant 50-60 degres F (10-15C), which is an absolutely ideal temperature for heat pumps. This "ground source" is obtained either by burying long loops of coolant pipe, or by simply pumping water from an aquifer, interchanging heat with the water, and letting it fall back into the aquifer.
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  • To install ground loops requires a LOT of trenching to supply a water based heat pump. And in my neck of the woods, pumping water out of the ground via a well and then putting it back requires tons of permits. Sorry, I wish it weren't that way. I looked into it when I built my house and it got ridiculously expensive. Why doesn't the OP simply replace the furnace?
    – George Anderson
    Mar 19, 2022 at 2:55
  • @GeorgeAnderson It's not THAT much trenching. I just build my house and have two horizontal loops for my heat pumps and it maybe takes up 100'x50'. Also, it was roughly the same price as I would have been for a similarly sized and similarly efficient conventional A/C. Once you account for the massive tax break.
    – TheValyreanGroup
    Mar 19, 2022 at 5:56
  • @GeorgeAnderson You can have a closed loop in a well bore, exchanging heat with the underground water, which presumably would significantly simplify the permitting process. But wells can be expensive. And if there aren't a lot of wells nearby that establish the depth of the water table, drilling can be an expensive gamble.
    – Llaves
    Mar 20, 2022 at 2:15
  • @Llaves that depends upon where you are, here in western Washington state there are tons of regulations not only that, like you said, drilling a well that has sufficient performance (enough flow) to service a ground water heat pump is a crap shoot.
    – George Anderson
    Mar 20, 2022 at 3:24

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