Electric-resistance annual heating cost

Why the simplest bill is the reference price

The relation has no efficiency term because the efficiency is unity. Joule heating converts electrical energy to heat completely, at the point of use, with nothing lost up a flue and no cycle to derate — which is why this page needs only two inputs where its siblings need three or four. Whatever the house demands as delivered heat is exactly what the meter records, and the tariff prices it.

That one-for-one conversion is what makes resistance the reference fuel. A heat pump’s coefficient is, read plainly, the number of times its winter undercuts this one; a furnace’s case is made by setting its fuel price and burner losses against this bill. Every comparison in the cluster is a discount quoted off the price this page states in full — which is why the plainest page is the one the others assume you have read.

Perfect conversion is not cheapness. The element wastes nothing, but it pays the full electricity price for every unit of warmth, with no multiple working in its favour — which is why, wherever tariffs are high, resistance is at once the simplest and the dearest common way to heat a home, and why the saving pages in this pack so often use it as the before picture.

The heat-load input is the building’s figure, not the appliance’s. The same season of delivered heat feeds the heat-pump page unchanged, because the house does not care what warms it; it comes from an energy audit, a degree-day estimate, or a past winter’s bills. For a house already heated by resistance, the reading runs backwards too — the heating share of a real winter’s consumption IS the load, measured by the meter at unity.

When this calculation is used

• Pricing a season of baseboard, strip or portable-heater warmth from an audited or bill-derived heat load and the household’s own tariff.
• Establishing the reference bill before opening a comparison page, so a quoted saving can be read against the cost it discounts.
• Sanity-checking a heat-pump proposal: the claimed saving should never exceed what this page says the resistance winter costs in full.
• Working an all-electric winter backwards — the heating share of a metered season, taken at unity, is the load the other pages need.

Worked example

Run the pack’s declared reference season: a family home whose winter demands an ordinary quantity of delivered heat, warmed entirely by electric resistance and billed at a mid-range residential tariff — the same house the heat-pump and comparison pages price by other means.

The engine returns the annual heating cost — one figure, because nothing stands between the load and the tariff. Read it as the ceiling of the cluster: the price of the season with no machine working in your favour, and the bill every comparison page starts from before subtracting anything.

Every figure in this example is produced by the certified engine when the calculator loads, checked against the signed pack’s declared test vectors; nothing on this page stores an answer. Hold the load and move only the tariff, and the bill follows in exact proportion — a resistance winter is pure exposure to the electricity price.

What each input represents

Assumptions and limits

• Every kilowatt-hour drawn becomes heat in the heated space: elements sited inside the envelope waste nothing, though ducted or garage-sited equipment can leak warmth the relation does not see.
• The heat load is taken as known and appliance-independent; estimating it belongs to the audit, the bills or the degree-day siblings in this pack.
• One flat tariff prices every unit; time-of-use windows, demand charges and seasonal rates must be blended into it beforehand.
• This is an operating cost only. Equipment, installation and maintenance sit outside the relation, in the payback calculators this pack carries as siblings.

What the guards protect against

• A zero heat load is refused — the pack ships the refusal as a declared test vector — because a house that demands no heat has no winter to price, and a costless zero would dress an empty input up as an answer.
• The heat load is bounded far above any dwelling’s demand, catching a lifetime total or watt-hours entered where kilowatt-hours belong.
• The tariff band refuses prices quoted in cents entered as dollars at one end, and figures no residential utility bills at the other — mistyped units, not markets.

Provenance

Heating-fuel cost-comparison method: cost of delivered heat as fuel price over efficiency, with electric resistance converting at unity

The annual heat load is multiplied by the electricity tariff to return the annual heating cost; because resistance conversion is one-for-one, delivered heat and purchased electricity are the same quantity and no efficiency term intervenes.

Screening and reference material, to be checked against the governing standard and a qualified engineer; not a design determination. The signed pack carries its own citation, which displays from the verified leaf when the calculator loads.