3.4 kW: enough for a 65 m² flat with two people
With gas heating and hot water, 3.4 kW is enough for a 65 m² flat with two people, as long as you don't run the most power-hungry appliances at the same time.
English · Original discussion in Spanish · Published
3.4 kW is enough for a 65 m² flat if you don't switch everything on at once
Is 3.4 kW of contracted power enough for a small flat with two people and all the usual appliances? The answer from those already living with that figure is a qualified yes: the key is not the contracted power, but not running the biggest consumers at the same time. Gas heating and hot water take the two great electricity hogs out of the equation, and that completely changes the calculation.
The starting scenario is specific: a flat of around 65 usable square metres, no air conditioning, with a fridge, dishwasher, washing machine, induction hob, oven and microwave, all from efficient ranges. Two people today, maybe three tomorrow. The power the home comes with is 3.4 kW versus the 4.6 kW of the current flat.
What people already living with 3.4 kW say
The consensus is broad. Those with 3.4 kW and the same appliances describe it as "more than enough" and add a single precaution: don't run two big appliances at the same time. Another similar case, a 60-square-metre flat with a microwave, oven, fridge, induction hob and TV, went from 4.6 to 3.45 kW with no incidents. And some go further: 2.3 kW with a washing machine, dishwasher and induction hob, with a monthly bill of around 20 euros.
The technical nuance comes from the nature of the appliances themselves. According to a calculation doing the rounds, an induction hob can reach 2,000 W, but rarely draws that continuously. A microwave is around 700 W. The oven and dishwasher are the biggest drains, and that's where the thermostat comes in: an oven at 180 degrees doesn't use the same as one at 250, and a dishwasher at 45 degrees doesn't behave like one at 60.
The real problem: smart meters and the ICP
The most repeated warning has nothing to do with the power itself, but with the mechanism that controls it. The ICP — the power control switch (interruptor de control de potencia) — is a sealed circuit breaker installed by the utility company that trips when the contracted limit is exceeded. On old meters it could be reset by hand; on digital smart meters, it cannot. If it trips too many times, the user is left without power until the company steps in.
That's where the trap in the more aggressive advice lies. Swapping the circuit breaker for one with a higher amperage is useless if the one tripping is the utility's, located upstream. And lowering the contracted power to save money carries a hidden risk: if the installation isn't properly protected with its main automatic breaker and its individual circuit breakers, the ICP may be acting as the general protection, which in a home with electric heating is a real danger.
The factor that changes everything: gas heating
The decisive variable is whether heating and hot water run on natural gas. With electric heating, 3.4 kW falls short in winter: an average radiator uses between 1 and 1.5 kW, and a 50 to 100-litre electric water heater between 1.5 and 2 kW. That alone brushes the limit. Without electric heating, the picture is entirely different.
There are extreme cases that confirm it: 180 square metres with 2.2 kW contracted, or five people in a house with butane rings and electric heaters that got by for years on 3.3 kW. The rule that keeps coming up is that if the breaker trips two or three times a year, you have too much contracted power.
How much you really save by lowering the power
The saving depends on the power term, which is paid per contracted kW. Going from 4.6 to 3.4 kW cuts the fixed part of the bill, and at 2.3 kW some suppliers automatically apply the bono social (Spain's subsidised electricity rate). Some report 25 euros a month at that power with all the usual appliances. The full calculation, broken down item by item, yields differences that surprise anyone who has never scrutinised their bill.
The counterpoint comes from the opposite experience: anyone who has lived with poorly distributed three-phase installations knows what it's like not to be able to cook and run the microwave at the same time. The majority recommendation for the case at hand is to start with 3.4 kW, avoid switching everything on simultaneously, and go up only if trips become frequent.
In the end, the answer to the initial question is the one nobody wants to hear: it depends on your habits. And on whether you're willing to wait for the washing machine to finish before turning on the oven.
Is 3.4 kW of contracted power enough for a small flat with two people and all the usual appliances? The answer from those already living with that figure is a qualified yes: the key is not the contracted power, but not running the biggest consumers at the same time. Gas heating and hot water take the two great electricity hogs out of the equation, and that completely changes the calculation.
The starting scenario is specific: a flat of around 65 usable square metres, no air conditioning, with a fridge, dishwasher, washing machine, induction hob, oven and microwave, all from efficient ranges. Two people today, maybe three tomorrow. The power the home comes with is 3.4 kW versus the 4.6 kW of the current flat.
What people already living with 3.4 kW say
The consensus is broad. Those with 3.4 kW and the same appliances describe it as "more than enough" and add a single precaution: don't run two big appliances at the same time. Another similar case, a 60-square-metre flat with a microwave, oven, fridge, induction hob and TV, went from 4.6 to 3.45 kW with no incidents. And some go further: 2.3 kW with a washing machine, dishwasher and induction hob, with a monthly bill of around 20 euros.
The technical nuance comes from the nature of the appliances themselves. According to a calculation doing the rounds, an induction hob can reach 2,000 W, but rarely draws that continuously. A microwave is around 700 W. The oven and dishwasher are the biggest drains, and that's where the thermostat comes in: an oven at 180 degrees doesn't use the same as one at 250, and a dishwasher at 45 degrees doesn't behave like one at 60.
The real problem: smart meters and the ICP
The most repeated warning has nothing to do with the power itself, but with the mechanism that controls it. The ICP — the power control switch (interruptor de control de potencia) — is a sealed circuit breaker installed by the utility company that trips when the contracted limit is exceeded. On old meters it could be reset by hand; on digital smart meters, it cannot. If it trips too many times, the user is left without power until the company steps in.
That's where the trap in the more aggressive advice lies. Swapping the circuit breaker for one with a higher amperage is useless if the one tripping is the utility's, located upstream. And lowering the contracted power to save money carries a hidden risk: if the installation isn't properly protected with its main automatic breaker and its individual circuit breakers, the ICP may be acting as the general protection, which in a home with electric heating is a real danger.
The factor that changes everything: gas heating
The decisive variable is whether heating and hot water run on natural gas. With electric heating, 3.4 kW falls short in winter: an average radiator uses between 1 and 1.5 kW, and a 50 to 100-litre electric water heater between 1.5 and 2 kW. That alone brushes the limit. Without electric heating, the picture is entirely different.
There are extreme cases that confirm it: 180 square metres with 2.2 kW contracted, or five people in a house with butane rings and electric heaters that got by for years on 3.3 kW. The rule that keeps coming up is that if the breaker trips two or three times a year, you have too much contracted power.
How much you really save by lowering the power
The saving depends on the power term, which is paid per contracted kW. Going from 4.6 to 3.4 kW cuts the fixed part of the bill, and at 2.3 kW some suppliers automatically apply the bono social (Spain's subsidised electricity rate). Some report 25 euros a month at that power with all the usual appliances. The full calculation, broken down item by item, yields differences that surprise anyone who has never scrutinised their bill.
The counterpoint comes from the opposite experience: anyone who has lived with poorly distributed three-phase installations knows what it's like not to be able to cook and run the microwave at the same time. The majority recommendation for the case at hand is to start with 3.4 kW, avoid switching everything on simultaneously, and go up only if trips become frequent.
In the end, the answer to the initial question is the one nobody wants to hear: it depends on your habits. And on whether you're willing to wait for the washing machine to finish before turning on the oven.
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Summary of a discussion on Burbuja.info - Foro de economía, actualidad y política., translated from Spanish and reviewed before publication. Read the full discussion (32 replies).
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