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Converting a 2-function gas furnace to an electric one - help me

GREGORY.1312 13479 12
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  • #1 18876918
    GREGORY.1312
    Level 2  
    Posts: 3
    Hello

    I want to replace the five gas combi function with an electric combi mode or something else (e.g. a heat pump)
    I need some advice

    I have an apartment of 65m2
    I use 1048m2 of gas annually on gas
    Which gives the amount of about PLN 2,200 per year

    What electric furnace should be put in its place to make it suitable and how much electricity will it consume?
    I am asking this because I already have a solar farm (4 kW) and I use 1.8 kW of electricity per year.

    I will replace the gas in the kitchen with an induction hob and ... I am also thinking about electric heating
    But I don't know how many such five will consume my electricity, since gas consumes 1048 m3 of gas

    I don't know how to convert it.

    Someone can help?
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  • #2 18876922
    karolark
    Level 42  
    Posts: 14271
    Help: 701
    Rate: 2469
    GREGORY.1312 wrote:
    Hello

    I want to replace the five gas combi function with an electric combi mode or something else (e.g. a heat pump)
    I need some advice

    I have an apartment of 65m2
    I use 1048m2 of gas annually on gas
    Which gives the amount of about PLN 2,200 per year

    What electric furnace should be put in its place to make it suitable and how much electricity will it consume?
    I am asking about it because I already have a photovoltaic (4 kW) and I use 1.8 kW of electricity per year.

    I will replace the gas in the kitchen with an induction hob and ... I am also thinking about electric heating
    But I do not know how many such five will consume my electricity, since gas consumes 1048 m3 of gas

    I don't know how to convert it.

    Someone can help?


    Do you have FV panels in your apartment?
    Do you use so much electricity a year?
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  • #4 18876934
    karolark
    Level 42  
    Posts: 14271
    Help: 701
    Rate: 2469
    Sure, the PC consumes less electricity, but the investment cost is considerable
    and I cannot imagine its installation in the apartment
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  • #5 18876935
    GREGORY.1312
    Level 2  
    Posts: 3
    Photovoltaic panels, of course, on the roof.
    This is the first step in my quitting gas.

    So far I have bought 4kW panels.
    With my current power consumption (1.8kW), I will also buy an induction hob (apparently it is an additional 0.8kW per year)

    And now I would like to know how much is needed for an electric heater kW with my apartment size of 65m2 and the current gas consumption of 1048m2

    What stove to buy and how much electricity will it consume?

    Added after 2 [minutes]:

    I know that a heat pump costs a lot, but how does it relate to heating tap water?
  • #6 18876949
    Anonymous
    Level 1  
  • #7 18876958
    ROWE
    Level 34  
    Posts: 1987
    Help: 239
    Rate: 529
    GREGORY.1312 wrote:
    I am asking this because I already have a solar farm (4 kW) and I use 1.8 kW of electricity per year.

    GREGORY.1312 wrote:
    With my current power consumption (1.8kW), I will also buy an induction hob (apparently it is an additional 0.8kW per year)


    Probably nothing will come of it, because so far you are confusing the concepts of power (kW) with consumption (kWh) and with their sizes.
  • #8 18876971
    Zbigniew Rusek
    Level 38  
    Posts: 3610
    Help: 394
    Rate: 1534
    Electricity for heating is always more expensive than gas, and in addition, gas becomes cheaper and electricity becomes more expensive. Besides, the durability of an electrical installation is not unlimited.
  • #9 18878226
    TomekO1976
    Level 17  
    Posts: 244
    Help: 11
    Rate: 59
    1048 m3 of gas equals 11,500 kWh. Assuming a gas boiler efficiency of 80%, you will need an additional 9,200 kWh for heating and hot water. The heat pump will reduce this requirement to around 2,600 kWh. The cost of the heat pump and photovoltaic panels from PLN 45,000 minus subsidies if you can use, for example, Clean Air. I think the payback time is around 10 years.
  • #10 18878293
    Anonymous
    Level 1  
  • #11 18880819
    GREGORY.1312
    Level 2  
    Posts: 3
    Currently, electricity costs about PLN 200 for 2 months, which gives PLN 1,200 per year plus PLN 2,200 for gas
    This amounts to PLN 3,400 per year
  • #12 18880898
    Anonymous
    Level 1  
  • #13 18885759
    Szczecin62
    Level 21  
    Posts: 309
    Help: 44
    Rate: 123
    Hello,
    Dude, if you are still at the question stage, listen to many experienced people, what have not been explained in numbers, and numbers are not discussed!
    Many of the above +/- have given you estimated costs and profits quite correctly and it will not balance you in any way. Understand that if it does not return in 5-7 years (and it does not return) and 15-20 years from the calculations, it means that it will never return!
    You are a typical victim of the (sorry) photovoltaic campaign anytime, anywhere!
    The truth is brutal, you are the last one to make money from it (if at all ...).
    You have photovoltaics for a lot of money, i.e. you produce a very exclusive form of energy and it would be foolish to turn it directly into heat! Yes, the operation calculation will be improved by the heat pump, but you will charge the business plan with the next cost of the heat pump!
    Without going into your realities:
    If you produce 1000 kWh of energy in the photovoltaic and even if you put it into the operator's "warehouse", you will receive 800 kWh, which gives savings of PLN 500 (assuming that 1 kWh costs you about PLN 65 on average).
    If you give the same 1000 kWh in summer and in winter you pick up the heaters in an electric boiler, you will save the same 800 kWh, but as an alternative to natural gas, it will be about 80 cubic meters of gas worth about PLN 90.
    So your profit will be lower by PLN 400 !!!
    The truth is brutal. You have access to natural gas, be happy and don't look for miraculous solutions. If you have an old boiler, replace it for a few thousand with a new condensing one, add a weather report so that the temperature of the boiler is not set by eye, add a room regulator to have another few zlotys of savings, and that's it.

Topic summary

✨ The discussion revolves around converting a gas combi furnace to an electric system or heat pump for a 65m2 apartment. The user seeks advice on suitable electric heating options, considering their annual gas consumption of 1048m3 (approximately 2,200 PLN) and existing 4 kW solar panels. Responses highlight that a heat pump is more energy-efficient, consuming significantly less electricity than electric heaters. Calculations suggest that the gas consumption translates to about 11,500 kWh annually, with a heat pump potentially reducing this to around 2,600 kWh. However, the high initial investment for heat pumps and photovoltaic systems raises concerns about long payback periods, estimated at 10 to 20 years. The discussion emphasizes the importance of understanding energy consumption versus costs and the potential inefficiency of converting solar energy directly into heat.
Generated by the language model.

FAQ

TL;DR: For a 65 m² flat using 1,048 m³ gas/year, "1048 m³ of gas equals 11,500 kWh"; a heat pump can drop demand to ~2,600 kWh. Use kWh, not kW, to size and compare. [Elektroda, TomekO1976, post #18878226]

Why it matters: This FAQ helps apartment owners decide if switching from a gas combi to electric or a heat pump (with PV) pays off and how to size it.

Quick Facts

How do I convert my annual gas use in m³ to kWh for heating comparisons?

Multiply annual gas volume by the energy content and boiler efficiency. The thread example converts 1,048 m³ to ~11,500 kWh of gas energy, then at ~80% boiler efficiency yields ~9,200 kWh delivered heat. Use that 9,200 kWh to compare electric options. [Elektroda, TomekO1976, post #18878226]

If I replace my gas boiler with a resistive electric boiler, how many kWh will it use?

Plan for roughly the same as your delivered heat need, because electric resistance is COP ≈ 1. Using the thread’s numbers, ~9,200 kWh/year of electricity would replace the gas boiler’s output. Size your service and tariff accordingly. [Elektroda, TomekO1976, post #18878226]

How much electricity would a heat pump use for the same apartment and load?

About 2,600 kWh/year for the example 9,200 kWh heat demand. That reflects an implied seasonal COP near 3.5. “1048 m³ of gas equals 11,500 kWh,” leading to 2,600 kWh on a heat pump. [Elektroda, TomekO1976, post #18878226]

Which is cheaper to run: electric boiler, heat pump, or gas?

Direct electric is typically the most expensive to run. A heat pump cuts electricity use roughly 3.5× versus resistive, but hardware costs more. Gas remains a strong baseline for operating cost in the thread’s scenario. “The heat pump will use much less electricity…” [Elektroda, Anonymous, post #18876928]

Can I install a heat pump in an apartment? What are the constraints?

Installation can be challenging in flats due to space, noise, and placement of the outdoor unit. One user noted, “I cannot imagine its installation in the apartment.” Check building rules, balcony loads, and hydronic compatibility before committing. [Elektroda, karolark, post #18876934]

How do I heat domestic hot water (DHW) with a heat pump that also does space heating?

Use a DHW cylinder and a three‑way valve controlled by the heat pump. The valve diverts output to either the cylinder or the central heating loop. Most branded systems support this mode natively. [Elektroda, Anonymous, post #18876949]

Is electricity for heating really more expensive than gas?

A forum expert stated that electricity for heating is always more expensive than gas, and also noted price trends. This applies especially to direct electric boilers. Heat pump economics depend on COP and tariffs. [Elektroda, Zbigniew Rusek, post #18876971]

How do I factor my 4 kW PV into the decision?

Offset your non‑heating usage first. One user equated PLN 100/month to ~1.5 MWh/year and roughly 1.5 kW of PV. Oversizing PV beyond your loads can be an over‑investment. Consider prosumer rules and export compensation limits. [Elektroda, Anonymous, post #18880898]

What payback should I expect if I switch from gas to heat pump + PV?

A modeled example showed ~PLN 45,000 upfront translating to ~19.5 years payback when compared against the current gas spend. Always compare incremental savings versus your existing gas baseline, not total bills. [Elektroda, Anonymous, post #18878293]

I’m mixing up kW and kWh. Which do I use to size and budget?

Use kWh for annual energy consumption and billing. Use kW for appliance power and peak capacity. One user flagged that confusing kW with kWh derails sizing and cost estimates. Correct units make calculators useful. [Elektroda, ROWE, post #18876958]

Is there a quick calculator to estimate costs and consumption?

Yes. The thread links to Vaillant’s online calculator for heating and DHW costs. Enter your dwelling data and energy prices to compare gas, electric, and heat pump scenarios. Treat outputs as planning‑grade estimates. [Elektroda, Anonymous, post #18876928]

What if I don’t switch—how can I still cut my gas bills cheaply?

Replace an old boiler with a condensing model. Add weather compensation and a room controller to optimize flow temperatures and schedules. A contributor emphasized these upgrades as cost‑effective versus full electrification. [Elektroda, Szczecin62, post #18885759]

What pitfalls should I watch for (edge cases)?

Over‑investing in PV or HP can stretch ROI beyond policy windows. Prosumer settlement benefits last about 15 years; a 19–20 year payback risks never recovering costs if rules change. Size systems to loads. [Elektroda, Anonymous, post #18880898]

How do I quickly estimate electricity needs from my gas bill? (3‑step)

  1. Convert gas: 1,048 m³ ≈ 11,500 kWh gross.
  2. Apply boiler efficiency: 80% → ~9,200 kWh delivered heat.
  3. Choose tech: Electric boiler ≈ 9,200 kWh/year; heat pump ≈ 2,600 kWh/year. Use these as planning baselines. [Elektroda, TomekO1976, post #18878226]

What are the current costs in the example thread?

The poster pays ~PLN 1,200/year for electricity and ~PLN 2,200/year for gas, totaling ~PLN 3,400/year. Use your own bills for accuracy, then model scenarios against this baseline. [Elektroda, GREGORY.1312, post #18880819]
Generated by the language model.
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